Regeneration treatment method for degradable high polymer material and use

Abstract

The present invention relates to a regeneration processing method for a degradable high polymer material, and a use, comprising the following steps: in a system in which an organic non-metallic catalyst and an aqueous solvent are present, performing degradation processing on a degradable high polymer material, to obtain a degradation product, the degradable high polymer material comprising one or more of a polyester material and a polycarbonate material, and the organic non-metallic catalyst being one or more selected from among a diphenyl phosphate, a binaphthyl phosphate and an organic base.

Description

Regeneration method and application of degradable polymer materials

[0001] Related applications

[0002] This application claims priority to Chinese patent application number CN2023108217699, filed on July 5, 2023, entitled “Regeneration Method and Application of Degradable Polymer Materials,” the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the technical field of polymer material recycling, and in particular to a regeneration method and application of degradable polymer materials. Background Art

[0004] With the continuous increase in the production and consumption of polymer materials both domestically and internationally, the recycling and utilization of polymer materials has become key to the sustainable development of the industry. Degradable polymer materials have attracted widespread attention due to their inherent degradability under specific conditions, especially polylactic acid, polycaprolactone, and polybutylene adipate / terephthalate. As environmentally friendly materials, these have replaced some traditional polymer materials (polyethylene terephthalate, polyvinyl chloride, polypropylene, etc.) in the market and are widely used in fields such as packaging and medicine, aiming to reduce the pollution caused by polymer materials to the environment.

[0005] The natural degradation rate of degradable polymer materials (such as polyester, polycarbonate, etc.) is slow. It takes two to three years to degrade to a low-molecular state in the ocean and soil. Even under industrial composting conditions, it takes about half a year to completely degrade. The uneven natural degradation rate of degradable polymer materials will form broken plastic particles rather than oligomers. The resulting microplastic problem is even more serious than that of petroleum-based plastics. Not only can it not achieve resource recycling, it will also cause secondary pollution to the environment. At the same time, traditional recycling methods such as thermal cracking, alcoholysis and hydrolysis have harsh processing conditions, small single processing volume and slow processing speed. The degradation products need to undergo tedious purification steps before they can be effectively reused.

[0006] Summary of the Invention

[0007] Based on this, according to various embodiments and examples of this application, the present application aims to provide a method for regenerating a degradable polymer material, which utilizes a low-cost, specific catalyst to achieve efficient degradation of the degradable polymer material. This method not only achieves rapid degradation, but also high conversion and reaction yield. This application also provides an application utilizing this regeneration method.

[0008] In a first aspect of the present application, a method for regenerating a degradable polymer material is provided.

[0009] In some embodiments, a method for regenerating a degradable polymer material is provided, comprising the following steps: degrading the degradable polymer material in a system in the presence of an organic non-metallic catalyst and an aqueous solvent to obtain a degradation product;

[0010] in,

[0011] The degradable polymer material includes one or more of polyester material and polycarbonate material;

[0012] The organic non-metallic catalyst is selected from one or more of diphenyl phosphate, binaphthol phosphate and organic bases, and the organic base is selected from one or more of nitrogen-containing heterobicyclic bases, 4-dimethylaminopyridine and phosphazene base compounds.

[0013] In some embodiments, in the regeneration method, the diphenyl phosphate has a structure shown in formula (I):

[0014] In formula (I), R 11 、R 12 、R 13 、R 14 、R 15 、R 21 、R 22 、R 23 、R 24 and R 25 Each is independently selected from any one of -H, halogen, -NO2, -CN, C1-C4 alkoxy, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of -NO2, -CN, halogen, and C1-C4 alkyl;

[0015] Optionally, in formula (I), R 11 、R 12 、R 13 、R 14 、R 15 、R 21 、R 22 、R 23 、R 24 and R 25 Each independently selected from any one of -H, halogen, -NO2, C1-C4 alkoxy, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen and C1-C4 alkyl;

[0016] The binaphthol phosphate has a structure shown in formula (II):

[0017] In formula (II), R3 and R3' can be independently selected from -H, -SiPh3 or Wherein, “*” indicates the attachment site of a covalent single bond;

[0018] R 41 、R 42 、R 43 、R 44 and R 45 Each independently selected from any one of -H, halogen, -NO2, -CN, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen, -NO2, -CN, phenyl, and C1-C4 alkyl; or R 41 、R 42 、R 43 、R 44 and R 45 At least two of them form a ring and participate in forming a fused ring, R 41 、R 42 、R 43 、R 44 and R 45 The uncyclic groups are each independently selected from any one of -H, halogen, -NO2, -CN, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen, -NO2, -CN, phenyl, and C1-C4 alkyl;

[0019] Optionally, R 41 、R 42 、R 43 、R 44 and R 45 Each independently selected from any one of -H, halogen, -NO2, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen, -NO2, phenyl, and C1-C4 alkyl; or R 41 、R 42 、R 43 、R 44 and R 45 At least two of them form a ring and participate in forming a fused ring, R 41 、R 42 、R 43 、R 44 and R 45The uncyclic groups are each independently selected from any one of -H, halogen, -NO2, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen, -NO2, phenyl, and C1-C4 alkyl;

[0020] The nitrogen-containing heterobicyclic base is selected from the structure shown in formula (III):

[0021] In formula (III), Y is -CH2-, -NH- or -N(CH3)-; n is 1 or 2;

[0022] The phosphazene base compound has a structure shown in formula (IV):

[0023] In formula (IV), R is halogen, C1-C4 alkyl or C1-C4 alkoxy.

[0024] In some embodiments, the regeneration method satisfies one or more of the following characteristics:

[0025] The number average molecular weight of the degradable polymer material is 10kDa to 250kDa;

[0026] The mass ratio of water to the degradable polymer material in the system is (0.01-10):1;

[0027] The mass ratio of the organic non-metallic catalyst to the degradable polymer material is (0.001-0.1):1;

[0028] The average degree of polymerization of the degradation product is ≤20.

[0029] In some embodiments, the regeneration method satisfies one or more of the following characteristics:

[0030] The degradable polymer material is selected from one or more of polylactic acid, polyglycolic acid, polyε-caprolactone, polylactic acid-glycolic acid copolymer, polyglycolic acid-ε-caprolactone copolymer, polylactic acid-ε-caprolactone copolymer, polyδ-valerolactone, polybutyrolactone, polybutylene succinate, polybutylene adipate / terephthalate, polybutylene succinate / adipate, polyhydroxyalkanoate and polytrimethylene carbonate;

[0031] Optionally, the degradable polymer material is selected from one or more of polylactic acid, polyglycolic acid, polyε-caprolactone, polylactic acid-glycolic acid copolymer, polyglycolic acid-ε-caprolactone copolymer, polylactic acid-ε-caprolactone copolymer, polyδ-valerolactone, polybutyrolactone, polybutylene succinate, polybutylene adipate / terephthalate, polyhydroxyalkanoate and polytrimethylene carbonate;

[0032] The diphenyl phosphate catalyst is selected from one or more of diphenyl phosphate, bis(4-nitrophenyl) phosphate, bis(4-fluorophenyl) phosphate, bis(4-trifluoromethylphenyl) phosphate, bis(4-chlorophenyl) phosphate, bis(4-methoxyphenyl) phosphate and bis(4-methylphenyl) phosphate;

[0033] Optionally, the diphenyl phosphate catalyst is selected from one or more of diphenyl phosphate, bis(4-nitrophenyl)phosphate and bis(2,6-dimethylphenyl)phosphate;

[0034] The binaphthol phosphate catalyst is selected from one or more of binaphthol phosphate, R-binaphthol phosphate, R-3,3'-bis(triphenylsilyl)binaphthol phosphonate and R-3,3'-bis(2,4,6-triisopropylphenyl)binaphthol phosphonate;

[0035] The organic base catalyst is selected from 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazidobicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 4-dimethylaminopyridine, tert-butylimino-tris(dimethylamino)phosphorane, 1-tert-butyl-2,2,4,4,4-penta(dimethylamino)-2Λ5,4Λ5-bis(phosphorus nitrogen-based compound) and cyclotriphosphazene base and 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylideneamino]-2Λ5,4Λ5-bis(phosphorus nitrogen-based compound) One or more.

[0036] In some embodiments, the regeneration method comprises the following steps: performing a first degradation treatment on the first degradable polymer material in the presence of the organic non-metallic catalyst and the aqueous solvent to obtain a first degradation product;

[0037] The i-th degradation product and the i+1-th degradable polymer material are mixed and subjected to the i+1-th degradation treatment to obtain the i+1-th degradation product, wherein i is an integer ≥1, and the i+1-th degradable polymer material includes at least the second degradable polymer material; the degradation treatment is terminated when i+1=n to obtain the n-th degradation product, wherein n is an integer ≥2, and the average degree of polymerization of the n-th degradation product is ≤20.

[0038] In some embodiments, the regeneration method satisfies one or more of the following characteristics:

[0039] The temperature of any degradation treatment is independently 125°C to 200°C;

[0040] The time of any degradation treatment is independently 0.1h to 5h, and can be optionally 0.25h to 5h;

[0041] The pressure of any degradation treatment is independently 1 atm-100 atm. Optionally, the pressure of any degradation treatment is independently 100±5 kPa.

[0042] In some embodiments, the regeneration method further includes the following steps: washing the degradation product with an organic solvent; wherein the organic solvent is selected from one or more of chloroform, petroleum ether, carbon disulfide, ether, dichloromethane, benzene, toluene and ethyl acetate.

[0043] In a second aspect of the present application, a low molecular weight composition is provided, which is a degradation product of a degradable polymer material. The low molecular weight composition is prepared according to the regeneration method described in the first aspect, wherein the average degree of polymerization of the low molecular weight composition is ≤20.

[0044] The third aspect of the present application provides a method for recycling degradable polymer materials, comprising the following steps: conducting a polymerization reaction using a low molecular weight composition as an initial raw material; wherein the low molecular weight composition is a degradation product prepared by the regeneration method described in the first aspect or the low molecular weight composition described in the second aspect.

[0045] A fourth aspect of the present application provides an application of an organic non-metallic catalyst in the degradation treatment of a degradable polymer material;

[0046] Wherein, the organic non-metallic catalyst and the degradable polymer material are as defined in the first aspect.

[0047] The details of one or more embodiments and examples of the present application are set forth in the accompanying drawings and description below. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0049] Figure 1 shows the sample product after chloroform cleaning and before cleaning in Example 1 of the present application. 1 H NMR spectrum.

[0050] Figure 2 is an optical photograph of the residues of the polylactic acid film disc of Experiment A1 of the present application at 8 hours (8h), 16 hours (16h), 24 hours (24h), 32 hours (32h), 48 hours (48h) and 72 hours (72h) after the start of the reaction.

[0051] Figure 3 shows the change in conversion rate (average value) of the reaction system over time in some examples of the present application; among them, in Tests A1 to A5, the polylactic acid film disc was placed in a pH = 1 aqueous solution containing 3.5 wt% diphenyl phosphate (DPP) (Test A1), deionized water (Test A2), a dry environment (3.5 wt% diphenyl phosphate DPP was mixed in the film) (Test A3), a pH = 1 hydrochloric acid solution (Test A4) and a pH = 13 NaOH aqueous solution (Test A5).

[0052] FIG4 is a graph showing the peak molecular weight (M) of the reaction system in some examples of the present application. peak ) changes with time; wherein, the reaction system of test A6 is polylactic acid pellets (pre-crushed to a diameter of <1 mm), diphenyl phosphate DPP (the mass ratio of DPP to polylactic acid pellets is 5%), the reaction temperature is 160°C oil bath, 2 drops of deionized water are added every 5 minutes, and the reaction is carried out for 0.5 hours; the difference between test A7 and test A6 is that no diphenyl phosphate DPP is added.

[0053] Figure 5 shows degradation tests using different polymer materials as substrates; Figure A shows a photograph of a mixed plastic (polyethylene terephthalate PET + polypropylene PP + polyethylene PE + polylactic acid PLA) before reaction; Figures B and C show photographs of the degradation product (B) and undegraded plastic (C) obtained after the mixed plastic was reacted; Figures D, E, and F show the DSC curves of polyethylene terephthalate PET, polypropylene PP, and polyethylene PE in the reaction substrate (mixed plastic) before and after treatment, respectively. m Is the melting point. DETAILED DESCRIPTION

[0054] The following is a clear and complete description of the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0055] The terms "embodiment" and "example" used herein are not necessarily to indicate that any embodiment described as "exemplary" is superior or preferable to other embodiments. Performance indicators in the examples of this application were tested using conventional test methods in the art, unless otherwise specified. It should be understood that the terms used in this application are intended solely to describe specific embodiments and are not intended to limit the disclosure of this application.

[0056] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0057] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0058] "Alkyl" refers to the residue remaining after removing one hydrogen atom from a hydrocarbon group containing single bonds between carbon atoms and between carbon atoms and hydrogen atoms. Phrases containing this term, such as "C1-C6 alkyl," refer to alkyl groups containing 1 to 6 carbon atoms, and each occurrence may independently be C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, or C6 alkyl.Suitable examples include, but are not limited to, ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 1-methylethyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 1-methylpropyl (s-Bu, s-butyl, -CH(CH3)CH2CH3), 2-methylpropyl (i-Bu, i-butyl, -CH2CH(CH3)2), 1,1-dimethylethyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n-pentyl, -CH2CH2CH 2CH2CH3), 1-methylbutyl (-CH(CH3)CH2CH2CH3), 1-ethylpropyl (-CH(CH2CH3)2), 1,1-dimethylpropyl (-C(CH3)2CH2CH3), 1,2-dimethylpropyl (-CH(CH3)CH(CH3)2), 3-methylbutyl (-CH2CH2CH(CH3)2), 2-methylbutyl (-CH2CH(CH3)CH2CH3), 2,2-dimethylpropyl (-CH2C(CH3)3), 1-hexyl (-CH2CH2CH2CH2CH2CH3), 1-methylpentyl (-CH(CH3)C H2CH2CH2CH3), 1-ethylbutyl (-CH(CH2CH3)CH2CH2CH3), 1,1-dimethylbutyl (-C(CH3)2CH2CH2CH3), 1,2-dimethylbutyl (-CH(CH3)CH(CH3)CH2CH3), 1,3-dimethylbutyl (-CH(CH3)CH2CH(CH3)2), 1-methyl-1-ethylpropyl (-C(CH3)(CH2CH3)2), 2-methyl-1-ethylpropyl (-CH(CH2CH3)CH(CH3)2), 1,1,2-trimethylpropyl (-C(CH3)2CH(CH3) 2), 1,2,2-trimethylpropyl (-CH(CH3)C(CH3)3, 2-methylpentyl (-CH2CH(CH3)CH2CH2CH3), 4-methylpentyl (-CH2CH2CH2CH(CH3)2), 3-methylpentyl (-CH2CH2CH(CH3)CH2CH3), 2-ethylbutyl (-CH2CH(CH2CH3)2), 2,3-dimethylbutyl (-CH2CH(CH3)CH(CH3)2), 3,3-dimethylbutyl (-CH2CH2C(CH3)3), 2,2-dimethylbutyl (-CH2C(CH3)2CH2CH3).

[0059] "Alkoxy" refers to a group having an -O-alkyl group, i.e., an alkyl group as defined above connected to the main chain structure via an oxygen atom. Phrases containing this term, for example, "C1-C4 alkoxy" means that the alkyl portion contains 1 to 4 carbon atoms, and each occurrence can be independently C1 alkoxy, C2 alkoxy, C3 alkoxy or C4 alkoxy. Suitable examples include, but are not limited to, methoxy (-O-CH3 or -OMe), ethoxy (-O-CH2CH3 or -OEt) and tert-butoxy (-OC(CH3)3 or -Ot-Bu).

[0060] "Halogen" or "halo" refers to -F, -Cl, -Br or -I.

[0061] "Phenyl" refers to -C6H5; alkyl-substituted phenyl includes alkyl substitution on at least one site of the phenyl group.

[0062] The terms "and / or", "or / and", and "and / or" used in this document include any one of two or more related listed items, and also include any and all combinations of the related listed items, including any combination of any two related listed items, any more related listed items, or all related listed items.

[0063] In this application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered continuous and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when a numerical interval only refers to an integer in the numerical interval, including the two endpoint integers of the numerical range and each integer between the two endpoints is equivalent to directly enumerating each integer. When multiple numerical ranges are provided to describe a feature or characteristic, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0064] As used herein, the terms "substantially" and "approximately" are used to describe values ​​that allow for small fluctuations. It should be understood that as long as the numerical range is within the allowed fluctuation range, it is within the semantic scope of "substantially" or "approximately". For example, "substantially" and "approximately" cover situations where there is no fluctuation. For example, they can mean less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Numerical data expressed or presented in a range format herein are used only for convenience and brevity and should therefore be flexibly interpreted to include not only the values ​​explicitly listed as the limits of the range, but also all independent values ​​or sub-ranges contained in the range. For example, a numerical range of "1% to 5%" should be interpreted to include not only the explicitly listed values ​​of 1% to 5%, but also the independent values ​​and sub-ranges within the range shown. Thus, within this numerical range are included individual values ​​such as 2%, 3.5%, and 4%, and subranges such as 1% to 3%, 2% to 4%, and 3% to 5%, etc. This principle also applies to ranges that list only one numerical value. Furthermore, this interpretation applies regardless of the breadth of the range or the characteristics described.

[0065] Herein, the terms "preferred," "better," "more preferred," and "suitable" are used solely to describe preferred implementations or examples and should not be construed as limiting the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, each "preferred" term is considered independent unless otherwise specified and there are no contradictions or mutual constraints.

[0066] In this application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0067] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions of the listed features.

[0068] Unless otherwise specified, the temperature parameters in this application allow for both constant temperature treatment and temperature fluctuations within a certain temperature range. It should be understood that the constant temperature treatment allows for temperature fluctuations within the accuracy range of instrument control. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are permitted.

[0069] In order to better illustrate the content of this application, numerous details are provided in some of the examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain details. In the examples, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the application.

[0070] Under the premise of no conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of this application.

[0071] Currently, the mainstream alternatives to traditional petroleum-based plastics on the market are biodegradable polyesters and polycarbonates, represented by polylactic acid. While these biodegradable materials can degrade under specific conditions, they typically require specialized industrial composting facilities. The materials currently in use far exceed the processing capacity of existing industrial composting plants. Furthermore, even under industrial composting conditions, the degradation cycle typically takes three to six months, and both the materials and their degradation products are directly discharged into the natural environment, making resource recycling impossible.

[0072] Commonly used biodegradable polymers such as polylactic acid, polycaprolactone, polybutylene succinate, and polybutylene adipate / terephthalate degrade very slowly under natural conditions, exhibiting no noticeable morphological changes even after being exposed to air for a year. Effective degradation of these polymers requires human intervention.

[0073] In order to better realize the treatment and recycling of degradable polymer materials, chemical recovery can be selected, and methods such as thermal cracking, alcoholysis and hydrolysis can be selected. The thermal cracking method has high reaction temperature, low yield of target product, many side reactions and easy racemization of product, which makes it difficult to obtain high-purity products. Alcoholysis is usually to treat waste materials with low alkyl alcohol or ethylene glycol under the action of a catalyst to recycle hydroxy acids or esters therein. For example, patent documents (US5264614A, US5264617A) report the alcoholysis recovery of polyhydroxyalkanoates (PHA) using low alkyl alcohols such as n-butanol as solvents, but it is necessary to add a large amount of strongly acidic catalysts (such as sulfuric acid), which is easy to corrode equipment, has a complicated process, is difficult to expand to industrial scale, and neutralization and water washing also produce a large amount of wastewater. There are also technical documents that use ionic liquids (CN102659590A), liquid Lewis acids (CN105017013A), CaO / MCF mesoporous alkaline molecular sieves (CN107382718A), alkaline low eutectic solvents (CN108837847A) and immobilized ionic liquids (CN110003009A) as catalysts to convert polylactic acid into corresponding lactate in solvents such as methanol. This has improved the problems of equipment corrosion, wastewater discharge and the inability to reuse catalysts to a certain extent, but these catalysts have not yet been commercialized, need to be prepared by themselves, have complicated steps, and do not have industrial transformation capabilities in the short term. The hydrolysis method has the problem of slow hydrolysis rate, which makes it difficult to recycle valuable products within a limited time. It usually requires high temperature and high pressure conditions and the catalysis of strong acid or strong base, and the single processing volume is small, which cannot meet actual needs. In general, the degradation rate of degradable polymer materials in traditional chemical recycling methods is slow, the conversion rate of polymer substrates is low, and the complex reaction system makes it difficult to separate the products after the reaction, resulting in low yield and easy to cause environmental pollution.

[0074] Therefore, there is an urgent need to develop a recycling method for biodegradable polymer materials with fast reaction speed, high conversion rate, high yield and green environmental protection, so as to convert biodegradable polyester / polycarbonate materials into products with high added value, realize the recycling of biodegradable polyester / polycarbonate materials, and promote the green development of the industry.

[0075] According to various implementation methods and various examples of the present application, the present application at least provides a regeneration method and application of a degradable polymer material.

[0076] In some embodiments, a method for regenerating a degradable polymer material comprises the following steps: degrading the degradable polymer material in the presence of an organic non-metallic catalyst and an aqueous solvent to produce a degradation product; the degradable polymer material comprises one or more of a polyester material and a polycarbonate material; and the organic non-metallic catalyst is selected from one or more of diphenyl phosphate, binaphthol phosphate, and an organic base. This method utilizes a specific organic non-metallic catalyst to efficiently degrade the degradable polymer material, achieving rapid degradation, high conversion rate, high reaction yield, and low cost; the degradation product can be effectively reused as a valuable chemical.

[0077] One embodiment of the present application utilizes a specific organic non-metallic catalyst to regenerate and recycle degradable polymer materials. The specific organic non-metallic catalyst employed has been screened through extensive experiments and has been found to be highly efficient in catalyzing the hydrolysis of degradable polymer materials such as polyesters and polycarbonates. The regeneration method for degradable polymer materials provided herein achieves a high conversion rate for the degradable polymer material, a low degree of polymerization of the degradation product (e.g., monomers or near-monomer levels can be obtained), and a high proportion of low-molecular-weight compositions (e.g., greater than 95%) in the system after the degradation reaction. Furthermore, the post-processing operation is simple, the recovery efficiency is high, the process is environmentally friendly, and the cost is low.

[0078] In the regeneration treatment method of the degradable polymer material provided in one embodiment of the present application, the catalytic degradation process of the degradable polymer material can be carried out at normal pressure and relatively low temperature, does not involve organic solvents, and does not require a strong acid or strong base environment. Not only does it not produce a large amount of wastewater, but it also has low corrosion to the reaction vessel and low requirements for processing equipment. In addition, it does not require a series of tedious steps such as concentration and multiple purification, which is convenient for industrial expansion of production. Most of the organic non-metallic catalysts used are commercialized and are cheap and easy to obtain. At the same time, these catalysts have stable properties, have no strict requirements on the temperature and humidity of the storage environment, and can also be recycled multiple times, which helps to further reduce costs.

[0079] The low molecular weight composition obtained by the regeneration treatment method can be directly used as a reaction raw material to prepare polymer materials or composite materials, thereby realizing the recycling of plastic waste.

[0080] The first aspect of the present application provides a method for regenerating and processing degradable polymer materials, which uses an organic non-metallic catalyst with a specific structure to regenerate and recover the degradable polymer materials. The specific organic non-metallic catalyst used has been found through a large number of experimental screenings to be able to efficiently catalyze the hydrolysis of degradable polymer materials such as polyester and polycarbonate.

[0081] In some embodiments, the organic non-metallic catalyst having a specific structure can be selected from cyclic phosphate diesters and organic base compounds. Further, the structure of the cyclic phosphate diester compound also has Acidic sites (-OH) and Lewis basic sites (P=O) play a role in promoting degradation, and non-limiting examples may include diphenyl phosphate-based organic non-metallic catalysts and binaphthol phosphate-based organic non-metallic catalysts.

[0082] In some embodiments, a method for regenerating a degradable polymer material is provided, comprising the following steps: degrading the degradable polymer material in a system in the presence of an organic non-metallic catalyst and an aqueous solvent to obtain a degradation product;

[0083] in,

[0084] The degradable polymer material includes one or more of polyester material and polycarbonate material;

[0085] The organic non-metallic catalyst is selected from one or more of diphenyl phosphate, binaphthol phosphate and organic bases. Further, the organic base is selected from one or more of nitrogen-containing heterobicyclic bases, 4-dimethylaminopyridine and phosphazene base compounds.

[0086] In some embodiments, the cyclic phosphodiester is an aromatic phosphodiester having Ar1-O-(HO)P(=O)-O-Ar2 A class of aromatic phosphate diesters having a structure, wherein Ar1 and Ar2 are each independently an aromatic group, further, the number of ring atoms of the aromatic ring can be 12 to 60, further, the number of ring atoms of the aromatic ring can be 12 to 56, and can also be selected from the interval consisting of any one or any two of the following ring atoms: 12, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58 and 60. Ar1 and Ar2 can each independently be a monovalent group (see the structure shown in Formula (I)). Ar1 and Ar2 can also be connected by a covalent single bond, so that Ar1, Ar2 and -O(HO)P(=O)-O- form a ring. For example, when Ar1 and Ar2 both contain a naphthalene ring, Ar1 and Ar2 can form a binaphthyl structure, some examples of which can be seen in Formula (II). In some embodiments, Ar1, Ar2 and -O(HO)P(=O)-O- form a seven-membered ring structure through the covalent single bond between Ar1 and Ar2. Further, Ar1 and Ar2 are each independently unsubstituted or substituted naphthyl, in which case a binaphthyl structure is formed between Ar1 and Ar2. Furthermore, the oxy groups on both sides of -O-(HO)P(=O)- are each connected to a ring-forming carbon atom of a naphthalene ring, as can be seen in Formula (II).

[0087] In some embodiments of the present application, the organic non-metallic catalyst of diphenyl phosphate refers to a catalyst having A class of compounds having a skeleton, wherein the two benzene rings can be independently unsubstituted or substituted, and further, the two benzene rings can be independently substituted by 0, one or more Q1, and any Q1 can be independently a substituent selected from the group consisting of halogen, -NO2, -CN, C1-C4 alkoxy, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and one or more Q a Substituted phenyl, any one Q a The substituents may be independently selected from the group consisting of -NO2, -CN, halogen and C1-C4 alkyl.

[0088] In some embodiments, the diphenyl phosphate-based organic non-metallic catalyst is a catalyst having A class of compounds having a skeleton, wherein the two benzene rings can be independently unsubstituted or substituted, and further, the two benzene rings can be independently substituted by 0, one or more Q1, and any Q1 can be independently a substituent selected from the group consisting of halogen, -NO2, C1-C4 alkoxy, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and one or more Q a Substituted phenyl, any one Q aThe substituents may be selected independently and plurally from the group consisting of halogen and C1-C4 alkyl.

[0089] In some embodiments of the present application, the organic non-metallic catalyst of the binaphthol phosphate type refers to a catalyst having A class of compounds having a skeleton, wherein the two naphthalene rings can be independently unsubstituted or substituted, further, the two naphthalene rings can be independently substituted by 0, one or more Q2, any Q2 can be independently a substituent selected from the group consisting of triphenylsilyl (-SiPh3, wherein Ph represents a phenyl group), a phenyl group, and a substituted phenyl group, further, the phenyl ring in the substituted phenyl group can be substituted by one or more substituents selected from the group consisting of halogen, -NO2, -CN, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and one or more Q b Substituted phenyl, any one Q b The substituents may be independently selected from the group consisting of halogen, -NO2, -CN, phenyl, and C1-C4 alkyl.

[0090] In some embodiments, the organic non-metallic catalyst of the binaphthol phosphate class is A class of compounds having a skeleton, wherein the two naphthalene rings can be independently unsubstituted or substituted, further, the two naphthalene rings can be independently substituted by 0, one or more Q2, any Q2 can be independently a substituent selected from the group consisting of triphenylsilyl (-SiPh3, wherein Ph represents a phenyl group), a phenyl group, and a substituted phenyl group, further, the phenyl ring in the substituted phenyl group can be substituted by one or more substituents selected from the group consisting of halogen, -NO2, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and one or more Q b Substituted phenyl, any one Q b The substituents may be independently selected from the group consisting of halogen, -NO2, phenyl, and C1-C4 alkyl.

[0091] In some embodiments, in the regeneration method, the diphenyl phosphate has a structure shown in formula (I):

[0092] In formula (I), R 11 、R 12 、R 13 、R 14 、R 15 、R 21 、R 22 、R 23 、R 24 and R 25Each is independently selected from any one of -H, halogen, -NO2, -CN, C1~C4 alkoxy, C1~C6 alkyl, halogen-substituted C1~C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the following group: -NO2, -CN, halogen and C1~C4 alkyl.

[0093] In some embodiments, in formula (I), R 11 、R 12 、R 13 、R 14 、R 15 、R 21 、R 22 、R 23 、R 24 and R 25 Each is independently selected from any one of -H, halogen, -NO2, C1~C4 alkoxy, C1~C6 alkyl, halogen-substituted C1~C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen and C1~C4 alkyl.

[0094] In some embodiments, in the regeneration method, the binaphthol phosphate has a structure shown in formula (II):

[0095] In formula (II), R3 and R3' can be independently selected from -H, -SiPh3 or Wherein, “*” indicates the attachment site of a covalent single bond;

[0096] R 41 、R 42 、R 43 、R 44 and R 45 Each independently selected from any one of -H, halogen, -NO2, -CN, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen, -NO2, -CN, phenyl, and C1-C4 alkyl; or R 41 、R 42 、R 43 、R 44 and R 45 At least two of them form a ring and participate in forming a fused ring, R 41 、R 42 、R 43 、R 44 and R 45The cyclic groups are independently selected from any one of -H, halogen, -NO2, -CN, C1~C6 alkyl, halogen-substituted C1~C6 alkyl, phenyl, and substituted phenyl, and the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the following group: halogen, -NO2, -CN, phenyl and C1~C4 alkyl.

[0097] In some embodiments, in formula (II), R 41 、R 42 、R 43 、R 44 and R 45 Each independently selected from any one of -H, halogen, -NO2, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen, -NO2, phenyl, and C1-C4 alkyl; or R 41 、R 42 、R 43 、R 44 and R 45 At least two of them form a ring and participate in forming a fused ring, R 41 、R 42 、R 43 、R 44 and R 45 The cyclic groups are independently selected from any one of -H, halogen, -NO2, C1~C6 alkyl, halogen-substituted C1~C6 alkyl, phenyl, and substituted phenyl, and the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the following group: halogen, -NO2, phenyl and C1~C4 alkyl.

[0098] In some embodiments, R in the structure of formula (I) 11 、R 12 、R 13 、R 14 、R 15 、R 21 、R 22 、R 23 、R 24 and R 25 Each is independently -H, -F, -Cl, -Br, -I, -NO2 or -CN.

[0099] In some embodiments, R in the structure of formula (I) 11 、R 12 、R 13 、R 14 、R 15 、R 21 、R 22 、R 23 、R24 and R 25 Each is independently selected from -H, -F, -Cl, -Br, -I, -NO2.

[0100] In some embodiments, R in the structure of formula (I) 11 、R 12 、R 13 、R 14 、R 15 、R 21 、R 22 、R 23 、R 24 and R 25 Each is independently selected from C1 to C4 alkoxy; further each can be independently selected from -OCH3, -OCH2CH3, -OCH2CH2CH3, -OCH(CH3)2, -OCH2CH2CH2CH3, -OCH2CH(CH3)2, -OCH(CH3)CH2CH3, -OC(CH3)3.

[0101] In some embodiments, R in the structure of formula (I) 11 、R 12 、R 13 、R 14 、R 15 、R 21 、R 22 、R 23 、R 24 and R 25Each is independently selected from C1 to C6 alkyl, i.e., C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl or C6 alkyl; further, each can be independently selected from: ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 1-methylethyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 1-methylpropyl (s-Bu, s-butyl, -CH(CH3)CH2CH3), 2-methylpropyl (i-Bu, i-butyl, -CH2CH(CH3)2), 1,1-dimethylethyl (t-Bu, t-butyl, -C(CH3) 3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 1-methylbutyl (-CH(CH3)CH2CH2CH3), 1-ethylpropyl (-CH(CH2CH3)2), 1,1-dimethylpropyl (-C(CH3)2CH2CH3), 1,2-dimethylpropyl (-CH(CH3)CH(CH3)2), 3-methylbutyl (-CH2CH2CH(CH3)2), 2-methylbutyl (-CH2CH(CH3)CH2CH3), 2,2-dimethylpropyl (-CH2C(CH3)3), 1-hexyl (-CH2CH2CH2CH2CH2CH3), 1-methylpentyl (-CH(CH3)CH2C H2CH2CH3), 1-ethylbutyl (-CH(CH2CH3)CH2CH2CH3), 1,1-dimethylbutyl (-C(CH3)2CH2CH2CH3), 1,2-dimethylbutyl (-CH(CH3)CH(CH3)CH2CH3), 1,3-dimethylbutyl (-CH(CH3)CH2CH(CH3)2), 1-methyl-1-ethylpropyl (-C(CH3)(CH2CH3)2), 2-methyl-1-ethylpropyl (-CH(CH2CH3)CH(CH3)2), 1,1,2-trimethylpropyl (-C(CH3)2CH(CH3)2), 1,2,2-trimethylpropyl (-CH(CH3)C(CH3 )3, 2-methylpentyl (-CH2CH(CH3)CH2CH2CH3), 4-methylpentyl (-CH2CH2CH2CH(CH3)2), 3-methylpentyl (-CH2CH2CH(CH3)CH2CH3), 2-ethylbutyl (-CH2CH(CH2CH3)2), 2,3-dimethylbutyl (-CH2CH(CH3)CH(CH3)2), 3,3-dimethylbutyl (-CH2CH2C(CH3)3) and 2,2-dimethylbutyl (-CH2C(CH3)2CH2CH3), as well as halogen-substituted C1~C6 alkyl; halogen-substituted C1~C6 alkyl, such as -CF3, -CF2CF3, -C(CF3)3, etc.

[0102] In some embodiments, R in the structure of formula (I) 11 、R 12 、R 13 、R 14 、R 15 、R 21 、R 22 、R 23 、R 24 and R 25 Each is independently selected from any one of phenyl and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen and C1-C4 alkyl.

[0103] In some embodiments, R in the structure of formula (I) 12 、R 13 、R 14 、R 15 、R 22 、R 23 、R 24 and R 25 For H.

[0104] In some embodiments, R in the structure of formula (I) 11 and R 21 are selected from the same group.

[0105] In some embodiments, the diphenyl phosphate has a structure shown in formula (I-1):

[0106] In some embodiments, R in the structure of formula (I) 11 、R 13 、R 14 、R 15 、R 21 、R 23 、R 24 and R 25 For H.

[0107] In some embodiments, R in the structure of formula (I) 12 and R 22 are selected from the same group.

[0108] In some embodiments, the diphenyl phosphate has a structure shown in formula (I-2):

[0109] In some embodiments, R in the structure of formula (I) 11 、R 12 、R 14 、R 15 、R 21 、R22 、R 24 and R 25 For H.

[0110] In some embodiments, R in the structure of formula (I) 13 and R 23 are selected from the same group.

[0111] In some embodiments, the diphenyl phosphate has a structure shown in formula (I-3):

[0112] In some embodiments, R in the structure of formula (I) 12 、R 13 、R 14 、R 22 、R 23 and R 24 For H.

[0113] In some embodiments, R in the structure of formula (I) 11 、R 15 、R 21 and R 25 are selected from the same group.

[0114] In some embodiments, the diphenyl phosphate has a structure shown in formula (I-4):

[0115] In some embodiments, R in the structure of formula (I) 12 、R 14 、R 22 and R 24 For H.

[0116] In some embodiments, R in the structure of formula (I) 11 、R 13 、R 15 、R 21 、R 23 and R 25 are selected from the same group.

[0117] In some embodiments, the diphenyl phosphate has a structure shown in formula (I-5):

[0118] In some embodiments, R3 and R3' in the structure of formula (II) are independently selected from -H, -SiPh3 “*” represents the attachment site.

[0119] In some embodiments, R in the structure of formula (II) 41 、R 42、R 43 、R 44 and R 45 Each is independently -H, -F, -Cl, -Br, -I, -NO2 or -CN.

[0120] In some embodiments, R in the structure of formula (II) 41 、R 42 、R 43 、R 44 and R 45 Each is independently selected from -H, -F, -Cl, -Br, -I, -NO2.

[0121] In some embodiments, R in the structure of formula (II) 41 、R 42 、R 43 、R 44 and R 45Each is independently selected from C1 to C6 alkyl, i.e., C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl or C6 alkyl; further, each can be independently selected from: ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 1-methylethyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 1-methylpropyl (s-Bu, s-butyl, -CH(CH3)CH2CH3), 2-methylpropyl (i-Bu, i-butyl, -CH2CH(CH3)2), 1,1-dimethylethyl (t-Bu, t-butyl, -C(CH3) 3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 1-methylbutyl (-CH(CH3)CH2CH2CH3), 1-ethylpropyl (-CH(CH2CH3)2), 1,1-dimethylpropyl (-C(CH3)2CH2CH3), 1,2-dimethylpropyl (-CH(CH3)CH(CH3)2), 3-methylbutyl (-CH2CH2CH(CH3)2), 2-methylbutyl (-CH2CH(CH3)CH2CH3), 2,2-dimethylpropyl (-CH2C(CH3)3), 1-hexyl (-CH2CH2CH2CH2CH2CH3), 1-methylpentyl (-CH(CH3)CH2C H2CH2CH3), 1-ethylbutyl (-CH(CH2CH3)CH2CH2CH3), 1,1-dimethylbutyl (-C(CH3)2CH2CH2CH3), 1,2-dimethylbutyl (-CH(CH3)CH(CH3)CH2CH3), 1,3-dimethylbutyl (-CH(CH3)CH2CH(CH3)2), 1-methyl-1-ethylpropyl (-C(CH3)(CH2CH3)2), 2-methyl-1-ethylpropyl (-CH(CH2CH3)CH(CH3)2), 1,1,2-trimethylpropyl (-C(CH3)2CH(CH3)2), 1,2,2-trimethylpropyl (-CH(CH3)C(CH3 )3, 2-methylpentyl (-CH2CH(CH3)CH2CH2CH3), 4-methylpentyl (-CH2CH2CH2CH(CH3)2), 3-methylpentyl (-CH2CH2CH(CH3)CH2CH3), 2-ethylbutyl (-CH2CH(CH2CH3)2), 2,3-dimethylbutyl (-CH2CH(CH3)CH(CH3)2), 3,3-dimethylbutyl (-CH2CH2C(CH3)3) and 2,2-dimethylbutyl (-CH2C(CH3)2CH2CH3), as well as halogen-substituted C1~C6 alkyl; halogen-substituted C1~C6 alkyl, such as -CF3, -CF2CF3, -C(CF3)3, etc.

[0122] In some embodiments, R in the structure of formula (II) 41 、R 42 、R 43 、R 44 and R 45 Each independently selected from any one of phenyl and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the following groups: halogen, -NO2, -CN, phenyl and C1~C4 alkyl substituted phenyl; for example, 4-ClC6H4, 4-NO2C6H4, 4-CH3C6H4, 4-CF3C6H4, 4-t-BuC6H4, 4-PhC6H4, 4-(2,4,6-(CH3)3C6H2)C6H4, 3,5-(CF3)2C6H3, 3,5-t-Bu2C6H3, 3,5-Ph2C6H3, 2,4,6-CH3C6H2, 2,4,6-(i-Pr)3C6H2. The alkyl substituted phenyl includes the substitution of alkyl on at least one site of the phenyl, for example, R 42 and R 44 are selected from phenyl groups substituted with multiple methyl groups, such as 2,4,6-(CH3)3C6H2, R3 and R3' can be independently selected from -5'-2,2",4,4",6,6"-hexamethyl-1,1':3",1"-terphenyl

[0123] In some embodiments, R in the structure of formula (II) 41 、R 42 、R 43 、R 44 and R 45 Each independently selected from any one of phenyl and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen, -NO2, phenyl and C1-C4 alkyl-substituted phenyl; for example, 4-ClC6H4, 4-NO2C6H4, 4-CH3C6H4, 4-CF3C6H4, 4-t-BuC6H4, 4-PhC6H4, 4-(2,4,6-(CH3)3C6H2)C6H4, 3,5-(CF3)2C6H3, 3,5-t-Bu2C6H3, 3,5-Ph2C6H3, 2,4,6-CH3C6H2, 2,4,6-(i-Pr)3C6H2. The alkyl-substituted phenyl includes substitution of at least one site of the phenyl by an alkyl group, for example, R 42 and R 44 When both are selected from phenyl groups substituted with multiple methyl groups, such as 2,4,6-(CH3)3C6H2, R3 and R3' can be independently selected from -5'-2,2",4,4",6,6"-hexamethyl-1,1':3",1"-terphenyl.

[0124] In some embodiments, R in the structure of formula (II) 41 、R 42 、R 43 、R 44 and R 45 Two or more substituents in form a fused ring; further, R 41 、R 42 、R 43 、R 44 and R 45 The fused ring formed is 1-naphthyl 2-naphthyl 4-β-naphthyl-phenyl 9-Anthracenyl 9-Fiki

[0125] In some embodiments, the structure shown in formula (II) can also be in its R configuration. or S configuration

[0126] In some embodiments, the organic base is selected from 1,8-diazabicyclo[5.4.0]undec-7-ene 1,5,7-Triazidobicyclo[4.4.0]dec-5-ene 7-Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene One or more of 4-dimethylaminopyridine and phosphazene base compounds.

[0127] In some embodiments, in the regeneration method, the organic base is selected from one or more of nitrogen-containing heterobicyclic bases, 4-dimethylaminopyridine, and phosphazene base compounds.

[0128] In some embodiments, the nitrogen-containing heterobicyclic base is selected from the group consisting of:

[0129] Formula (III), Y is -CH 2- , -NH- or -N(CH3)-; n is 1 or 2.

[0130] In some embodiments, the phosphazene base compound has a structure shown in formula (IV):

[0131] In formula (IV), R is halogen, C1-C4 alkyl or C1-C4 alkoxy. Phosphazene base compounds refer to monomers or polymers thereof, such as tert-butylimino-tris(dimethylamino)phosphorane 1-tert-butyl-2,2,4,4,4-penta(dimethylamino)-2Λ5,4Λ5-bis(phosphorus nitrogen compound) Cyclotriphosphazene base (such as ) and 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylideneamino]-2Λ5,4Λ5-linked di(phosphorus nitrogen compound)

[0132] In some embodiments, the diphenyl phosphate catalyst is selected from one or more of diphenyl phosphate, bis(4-nitrophenyl)phosphate, bis(4-fluorophenyl)phosphate, bis(4-trifluoromethylphenyl)phosphate, bis(4-chlorophenyl)phosphate, bis(4-methoxyphenyl)phosphate and bis(4-methylphenyl)phosphate.

[0133] In some embodiments, the diphenyl phosphate catalyst is selected from one or more of diphenyl phosphate, bis(4-nitrophenyl)phosphate, and bis(2,6-dimethylphenyl)phosphate.

[0134] In some embodiments, the binaphthol phosphate catalyst is selected from one or more of binaphthol phosphate, R-binaphthol phosphate, R-3,3'-bis(triphenylsilyl)binaphthol phosphonate, and R-3,3'-bis(2,4,6-triisopropylphenyl)binaphthol phosphonate.

[0135] In some embodiments, the organic base catalyst is selected from 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazidobicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 4-dimethylaminopyridine, tert-butylimino-tris(dimethylamino)phosphorane, 1-tert-butyl-2,2,4,4,4-penta(dimethylamino)-2Λ5,4Λ5-bis(phosphorus nitrogen-based compound) and cyclotriphosphazene base and 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylideneamino]-2Λ5,4Λ5-bis(phosphorus nitrogen-based compound) One or more.

[0136] In some embodiments, in the regeneration method, the diphenyl phosphate is selected from diphenyl phosphate (DPP), bis(4-nitrophenyl) phosphate (BNPP), bis(4-fluorophenyl) phosphate (BFPP), bis(4-trifluoromethylphenyl) phosphate (BTFPP), bis(4-methylphenyl) phosphate (BMPP), bis(4-methoxyphenyl) phosphate (BMOPP), bis(2,6-xylyl) phosphate (DXP), and the binaphthol phosphate is selected from binaphthol phosphate (1,1'-binaphthyl-2,2'-diyl hydrogenphosphate (BNDHP), R-binaphthol phosphate ((R)-(-)-1,1'-binaphthyl-2,2'-diyl hydrogenphosphate, R-BNDHP), R-3,3'-bis(triphenylsilyl)binaphthol phosphonate ((R)-(-)-3,3'-bis(triphenylsilyl)-1,1'-binaphthyl-2,2'-diylhydrogenphosphate, R-TiPSY), R-3,3'-bis(2,4,6-triisopropylphenyl)binaphthol phosphonate ((R)-3,3'-Bis(2,4,6-trisopropylphenyl)-1,1'-binapthyl-2,2'-diyl hydrogenphosphate, referred to as R-TRIP, the organic base is selected from 1,8-diazabicyclo[5.4.0]undec-7-ene (1,8-diazabicyclo[5.4.0]undec-7-ene, referred to as DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (1,5,7-triazabicyclo[4.4.0]dec-5-ene, referred to as TBD), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, referred to as TBD),0]dec-5-ene (MTBD), 4-dimethylaminopyridine (DMAP), and cyclic trimeric phosphazene base (CTPB).

[0137] In some embodiments, in the regeneration method, the diphenyl phosphate is selected from diphenyl phosphate, bis(4-nitrophenyl)phosphate, and bis(2,6-dimethylphenyl)phosphate; the binaphthol phosphate is selected from binaphthol phosphate, R-binaphthol phosphate, R-3,3'-bis(triphenylsilyl)binaphthol phosphonate, and R-3,3'-bis(2,4,6-triisopropylphenyl)binaphthol phosphonate; and the organic base is selected from one or more of 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazidobicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 4-dimethylaminopyridine, and cyclotriphosphazene base.

[0138] In some embodiments, the organic non-metal catalyst may be selected from diphenyl phosphates, binaphthol phosphates, and organic bases. For example, one or more of diphenyl phosphate, bis(4-nitrophenyl)phosphate, bis(4-fluorophenyl)phosphate, bis(4-trifluoromethylphenyl)phosphate, bis(4-methylphenyl)phosphate, bis(4-methoxyphenyl)phosphate, bis(2,6-dimethylphenyl)phosphate, binaphthol phosphate, R-binaphthol phosphate, R-3,3'-bis(triphenylsilyl)binaphthol phosphonate, R-3,3'-bis(2,4,6-triisopropylphenyl)binaphthol phosphonate, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 4-dimethylaminopyridine and cyclotriphosphazene base. Most of the organic non-metallic catalysts selected above are mature commercial products. They are not only inexpensive and readily available, but also capable of catalyzing the efficient hydrolysis of degradable polymer materials, producing degradation products with low degrees of polymerization (e.g., close to monomers or oligomers with a degree of polymerization below 10). The low-molecular-weight degradation products obtained by the methods provided herein can be reused as raw materials, for example, in the preparation of polymers, achieving efficient closed-loop recycling of degradable polymer waste.

[0139] In some embodiments, the organic non-metallic catalyst may be selected from diphenyl phosphate, binaphthol phosphate, and organic bases, such as diphenyl phosphate, bis(4-nitrophenyl)phosphate, bis(2,6-dimethylphenyl)phosphate, binaphthol phosphate, R-binaphthol phosphate, R-3,3'-bis(triphenylsilyl)binaphthol phosphonate, R-3,3'-bis(2,4,6-triisopropylphenyl)binaphthol phosphonate, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazidobicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 4-dimethylaminopyridine, and one or more cyclotriphosphazene bases.

[0140] In the above-mentioned regeneration method for degradable polymer materials, the conversion rate of the degradable polymer material is high, the degree of polymerization of the degradation product is low (e.g., close to the monomer level), and the low molecular weight composition in the system after the degradation reaction can achieve a high proportion (e.g., exceeding 95%). In addition, this treatment method has low equipment requirements, simple post-processing operations, environmentally friendly process, and low cost.

[0141] Understandably, the regeneration treatment method can efficiently degrade the degradable polymer material into monomers and / or oligomers. The degree of degradation can also be controlled within a certain range by adjusting the reaction raw materials and process parameters (such as the content of water in the reaction system, the content of the catalyst, the reaction time, the reaction temperature and the reaction pressure, etc.), i.e., obtaining degradation products with a certain molecular weight and distribution and / or a certain conversion rate. The degradation products with a certain molecular weight and distribution and / or a certain conversion rate can be used directly or conveniently as raw materials for polymerization reactions to prepare degradable polymer materials under conditions such as without purification or under conditions of simple separation treatment.

[0142] In the regeneration method of the first aspect of the present application, after the degradation treatment, the degradable polymer material is degraded into products with reduced molecular weight.

[0143] In some embodiments, the degradation products are substantially low molecular weight products. In this application, unless otherwise specified, low molecular weight products mainly refer to degradation products with a molecular weight of ≤1500 Da.

[0144] Unless otherwise specified, the terms “oligomer” and “oligomer” in this application have the same meaning and can be used interchangeably.

[0145] In some embodiments, degradation products may include monomers and / or oligomers at near monomer levels.

[0146] Unless otherwise specified, the oligomers or oligomers in this application mainly refer to polymers with a molecular weight of ≤1500 Da and containing fewer repeating units.

[0147] Some molecules in the degradation products may be water-soluble when the molecular weight is low (e.g., PLA oligomer molecular weight ≤ 500 Da, corresponding to degree of polymerization ≤ 6.9). Therefore, the water-soluble molecules in the degradation products are recorded as "water-soluble small molecules."

[0148] Unless otherwise specified, the term "near monomer-level oligomers" in this application mainly refers to oligomers with a degree of polymerization ≤ 10, which may also be referred to as "quasi-monomer oligomers" or "quasi-monomer oligomers".

[0149] Taking polylactic acid (PLA) in polyester materials as an example, PLA can be continuously degraded in the presence of an organic non-metallic catalyst and water to form low-molecular-weight degradation products consisting essentially of monomers and / or oligomers (e.g., monomers and / or oligomers near the monomer level). These low-molecular-weight degradation products can be directly used as raw materials for efficient polymerization reactions to produce polymers with a certain molecular weight (e.g., number-average molecular weight ≥50 kDa). Furthermore, during the regeneration process of the polylactic acid material using the aforementioned method (in the presence of an organic non-metallic catalyst and water), the degree of polymerization of the degradation products in the reaction system can be controlled to a certain level (e.g., ≤8) by appropriately adjusting the raw material ratio and process parameters. The degradation products in the degradation product system can then be used to prepare lactide, and then a high-molecular-weight polymer (e.g., number-average molecular weight ≥150 kDa) can be produced using lactide as the raw material.

[0150] In some embodiments, in the regeneration method, the number average molecular weight of the degradable polymer material is 10kDa to 250kDa, further can be 10kDa to 150kDa, further can be 10kDa to 130kDa, and can also be selected from any one of the following number average molecular weight values ​​or an interval consisting of any two number average molecular weight values: 10kDa, 20kDa, 30kDa, 40kDa, 50kDa, 60kDa, 70kDa, 80kDa, 90kDa, 100kDa, 110kDa, 120kDa, 130kDa, 140kDa, 150kDa, 160kDa, 170kDa, 180kDa, 190kDa, 200kDa, 210kDa, 220kDa, 230kDa, 240kDa, 250kDa, etc.

[0151] In some embodiments, in the regeneration method, the weight average molecular weight of the degradable polymer material is 10kDa to 500kDa, further 10kDa to 250kDa, further 30kDa to 230kDa, and can also be selected from any one of the following weight average molecular weight values ​​or an interval consisting of any two weight average molecular weight values: 10kDa, 20kDa, 30kDa, 40kDa, 50kDa, 60kDa, 70kDa, 80kDa, 90kDa, 100kDa, 110kDa, 120kDa, 130kDa, 140kDa, 150kDa, 160kDa, 170kDa, 180kDa, 190kDa, 200kDa, 210kDa, 220kDa, 230kDa, 240kDa, 250kDa, 260kDa, 270kDa, 280kDa, 290kDa, 300kDa, 310kDa, 320kDa, 330k Da, 340kDa, 350kDa, 360kDa, 370kDa, 380kDa, 390kDa, 400kDa, 410kDa, 420kDa, 430kDa, 440kDa, 450kDa, 460kDa, 470kDa, 480kDa, 490kDa, 500kDa, etc.

[0152] In some embodiments, in the regeneration method, the mass ratio of water in the system to the degradable polymer material is (0.01-10):1, further can be (0.1-1):1, further can be (0.08-0.33):1:, and can also be selected from any one of the following mass ratios or an interval consisting of any two mass ratios: (0.01:1), (0.02:1), (0.03:1), (0.04:1), (0.05:1), (0.06:1), (0.07:1), (0.08:1), (0.083:1), (0.1:1), (0.15:1), (0.156:1) (0.2:1), (0.25:1), (0.3:1), (0.31:1) : 1), (0.32:1), (0.33:1), (0.34:1), (0.35:1), (0.36:1), (0.37:1), (0.38:1), (0.39:1), (0.4:1), (0.5:1), (0.6:1), (0.7:1), (0.8:1), (0.9:1), (1:1), (1.3:1), (1.5:1), (2:1), (2.5:1), (3:1), (3.5:1), (4:1), (4.5:1), (5:1), (5.5:1), (6:1), (6.5:1), (7:1), (7.5:1), (8:1), (8.5:1), (9:1), (9.5:1), (10:1). A more appropriate water content relative to the mass ratio of the degradable polymer material is more conducive to increasing the degradation rate of the degradable polymer material. If the water content in the system is too high relative to the mass ratio of the degradable polymer material, the internal temperature of the system is difficult to exceed the boiling point of the solvent (for example, 100°C for water) under normal pressure, which slows down the reaction process. In addition, the water as a raw material will boil violently and evaporate in large quantities, posing certain operational risks. If the water content in the system is too low relative to the mass ratio of the degradable polymer material, the amount of raw material participating in the reaction may be insufficient, the probability of contact between the reactants may be reduced, the reaction rate may be slowed, and the final product may have a higher degree of polymerization.

[0153] In some embodiments, in the regeneration method, the mass ratio of the organic non-metallic catalyst to the degradable polymer material is (0.001-0.1):1, further can be (0.01-0.05:1), further can be (0.035-0.05:1), and can also be selected from any one of the following mass ratios or an interval consisting of any two mass ratios: (0.001:1), (0.002:1), (0.003:1), (0.004:1), (0.005:1), (0.006:1), (0.007:1), (0.008:1), (0.0088:1) , (0.009:1), (0.01:1), (0.015:1), (0.02:1), (0.025:1), (0.03:1), (0.031:1), (0.032:1), (0.033:1), (0.034:1), (0.035:1), (0.036:1), (0.037:1), (0.038:1), (0.039:1), (0.04:1), (0.045:1), (0.05:1), (0.06:1), (0.07:1), (0.08:1), (0.09:1), (0.1:1), etc. A more appropriate catalyst amount relative to the mass ratio of the degradable polymer material is more conducive to reducing the economic cost of the recycling scheme. If the mass ratio of the catalyst to the degradable polymer material is too high, the use of a large amount of catalyst increases the raw material cost of the regeneration process; if the mass ratio of the catalyst to the degradable polymer material is too low, it may cause the degradation rate to be too slow, increasing time cost and energy consumption.

[0154] The degradation treatment of degradable polymer materials can be carried out under the condition of small amount of catalyst, with high catalytic efficiency and low cost.

[0155] In some embodiments, in the regeneration method, the average degree of polymerization of the degradation product is ≤20, further ≤15, and further ≤10, and can be selected from any one of the following average degree of polymerization values ​​or an interval consisting of any two average degree of polymerization values: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc. The average degree of polymerization of the degradation product can also be selected from any one of the following ranges, for example, 1-20, 1-15, 1-10, 2-20, 2-15, 2-12, 2-10, 2.3-9.6, etc.

[0156] Average degree of polymerization Analytical method: number average molecular weight (M n )÷repeating unit molecular weight. n=121kDa) raw material as an example, the molecular weight of its repeating unit is 72Da, and the average degree of polymerization is calculated by deducting the molecular weight of the end group 18Da from the number average molecular weight.

[0157] In some embodiments, in the regeneration method, the molar percentage of monomers in the degradation product is ≥30%, further ≥50%, and even further ≥80%. It can also be selected from any of the following molar percentage values, or a range consisting of any two of the following molar percentage values: 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 80%, 90%, etc. The molar percentage of monomers in the degradation product can also be selected from any of the following ranges, for example, 30%-60%, 30%-70%, 30%-80%, 30%-90%, 30%-100%, etc. It is understood that when degrading a degradable polymer material using the aforementioned regeneration method, the molar percentage of monomers in the degradation product can increase with increasing degradation time. In this application, unless otherwise specified, the molar percentage of monomers in the degradation product refers to the percentage of the moles of monomers to the total moles of the degradation product.

[0158] Taking the degradation product of polylactic acid as an example, it was dissolved in DMSO-d6 and characterized by Fourier transform nuclear magnetic resonance spectroscopy. 1 The molar percentage of lactic acid (lactic acid content) was calculated from the HNMR spectrum using the following formula:

[0159] Among them, I 1.23 is the integral value of the characteristic peak of methyl group (HOOCCH(CH3)OH) of lactic acid monomer at 1.23 ppm, I 1.27 It is the integral value of the characteristic peak at 1.27 ppm corresponding to the terminal methyl group (-COCH(CH3)OH) of lactic acid oligomers. It is understandable that when different batches are tested, the chemical shifts of the characteristic peaks at 1.23 ppm and 1.27 ppm may shift. However, those skilled in the art can determine the measured chemical shifts according to the characteristic peak attribution method. 1 The characteristic peaks corresponding to 1.23 ppm and 1.27 ppm in the H NMR spectrum.

[0160] In some embodiments, in the regeneration method, the mass proportion of low molecular weight products relative to the degradation products in the degradation products is ≥80%, further ≥90%, and further ≥95%.

[0161] In this application, unless otherwise specified, the mass percentage of low molecular weight products in the system refers to the weight percentage of low molecular weight products in the degradation products. In this application, the standard for considering that all the products in the reaction system are low molecular weight products is that the degradation products are detected by gel permeation chromatography (GPC) and Fourier transform nuclear magnetic resonance (NMR) spectrometer, and no polymer characteristic peaks appear. Taking the degradation products of PLA as an example, the elution peak in the GPC spectrum is shifted backward as a whole, and the signal of the peak corresponding to the molecule with a molecular weight of more than 1500Da is basically not observed. 1 In the H NMR spectrum, the signals of the characteristic methyl peak (1.5-1.6 ppm) and the characteristic methine peak (5.3-5.5 ppm) corresponding to the polymer were basically not observed.

[0162] In some embodiments, in the regeneration method, the mass percentage of the low molecular weight products in the degradation products relative to the total mass of the degradation products is ≥80%, further ≥90%, and further ≥95%.

[0163] In some embodiments, in the regeneration method, the water-soluble small molecule conversion rate is ≥20%, and can further be ≥23%, and can also be selected from any one of the following water-soluble small molecule conversion rate values ​​or an interval consisting of any two water-soluble small molecule conversion rate values: 20%, 23.7%, 25%, 30%, 32.6%, 35%, 40%, 45%, 50%, 53%, 55%, 60%, 61.6%, 65%, 70%, 72.1%, 74.1%, 75%, 80%, 85%, 86%, 88.3%, 90%, 90.4%, 91%, 92.8%, 95%, 99.2%, etc. It can be understood that when the degradable polymer material is degraded using the above regeneration method, the water-soluble small molecule conversion rate in the degradation product can be higher as the degradation treatment time increases.

[0164] In this application, unless otherwise specified, the conversion rate of a polymer raw material into water-soluble small molecules (hereinafter referred to as the "water-soluble small molecule conversion rate") refers to the ratio of the amount of the initial raw material that has been degraded and dissolved in water after the system continues to react until the preset termination or termination condition, to the amount of the initial raw material. More specifically, the mass ratio can be used as the standard for calculation and judgment. Numerically, the "water-soluble small molecule conversion rate" can be calculated based on the mass percentage of the water-soluble product (corresponding to the water-soluble small molecule) in the degradation product relative to the degraded raw material (i.e., the polymer raw material).

[0165] Calculation method for the conversion rate of water-soluble small molecules: The degradation product was placed in deionized water and stirred at room temperature for 0.5 h to dissolve. After centrifugation, the insoluble precipitate was collected, freeze-dried, and weighed. The conversion rate (mass ratio) of the polymer to the water-soluble small molecules was calculated using the following formula:

[0166] Among them, m input is the mass of the polymer before reaction, m residue is the mass of the insoluble matter remaining after the reaction.

[0167] In some embodiments, in the regeneration method, the polydispersity index (PDI) of the degradable polymer material is ≤3.3, further can be 1 to 3.3, and further can be 1 to 3.27.

[0168] In this application, unless otherwise specified, the polydispersity index (PDI) is used to describe the molecular weight distribution of polymers. The calculation method of the polydispersity index (PDI) is M w Divide by M n The larger the value, the wider the molecular weight distribution. In terms of numerical value, PDI can also be equal to molar mass dispersity (denoted as D M ).

[0169] In some embodiments, the degradable polymer material is selected from poly(lactic acid), poly(glycolic acid), poly(ε-caprolactone), poly(PCL), poly(lactic-co-glycolic acid), poly(PCGA), poly(lactic-co-caprolactone), poly(PCLA), poly(δ-valerolactone), poly(PVL), poly(β-butyrolactone), poly(PBS), poly(butylene succinate), poly(butylene adipate), poly(butylene terephthalate), poly(lactic-co-glycolic acid), poly(PLGA), poly(PCGA), poly(lactic-co-caprolactone), poly(PCLA), poly(δ-valerolactone), poly(PVL), poly(β-butyrolactone), poly(PBS), poly(butylene adipate), poly(butylene terephthalate), poly(butylene terephthalate), poly(lactic-co-caprolactone), poly(lactic-co-caprolactone), poly(PCLA), poly(PVL), poly(β-butyrolactone), poly(PBL), poly(butylene succinate), poly(PBS), poly(butylene adipate), poly(butylene terephthalate), poly(lactic-co-glycolic acid), poly(PLGA), poly(PCGA), poly(lactic-co-caprolactone), poly(PCLA), poly(PVL), poly(PVL), poly(β-butyrolactone), poly(PBL), poly(butylene succinate), poly(PBS), poly(butylene adipate), poly(butylene terephthalate), poly(lactic-co-glycolic acid), poly(PLGA), poly(PCGA), poly(lactic-co-caprolactone), poly(PCLA), poly(lactic-co-caprolactone), poly( One or more of polyols (poly(terephthalate), referred to as PBAT), polyhydroxyalkanoates (PHA) and polytrimethylene carbonate (PTMC).

[0170] In some embodiments, the regeneration method includes the following steps: in the system where the organic non-metallic catalyst and the aqueous solvent are present, performing a first degradation treatment on the first degradable polymer material to obtain a first degradation product; mixing the i-th degradation product and the i+1-th degradable polymer material, performing an i+1-th degradation treatment to obtain the i+1-th degradation product, wherein i is an integer ≥1, and the i+1-th degradable polymer material includes at least the second degradable polymer material; ending the degradation treatment when i+1=n to obtain the n-th degradation product, wherein n is an integer ≥2, and the average degree of polymerization of the n-th degradation product is ≤10.

[0171] In the present application, degradable polymer materials and water are continuously added to the degradation products, the content of the catalyst in the reaction system is reduced, and a secondary degradation reaction is carried out, and oligomers and / or monomers corresponding to the degradable polymer materials can still be obtained. That is, the regeneration treatment of the degradable polymer materials can be carried out continuously, which is conducive to industrial continuous production.

[0172] Taking n=2 as an example, the regeneration method includes the following steps:

[0173] (1) performing a first degradation treatment on a first degradable polymer material in the presence of the organic non-metallic catalyst and the aqueous solvent to obtain a first degradation product;

[0174] (2) mixing the first degradation product and the second degradable polymer material, and performing a second degradation treatment to obtain a second degradation product. The average polymerization degree of the second degradation product can refer to the above definition, for example, ≤20, further for example, ≤10, etc.

[0175] Taking n=4 as an example, in the system where the organic non-metallic catalyst and the aqueous solvent exist, the first degradable polymer material is subjected to a first degradation treatment to obtain a first degradation product;

[0176] mixing the first degradation product and the second degradable polymer material, performing a second degradation treatment, and obtaining a second degradation product;

[0177] mixing the second degradation product and the third degradable polymer material, performing a third degradation treatment, and obtaining a third degradation product;

[0178] The third degradation product and the fourth degradable polymer material are mixed and subjected to a fourth degradation treatment to obtain a fourth degradation product; the average polymerization degree of the fourth degradation product can refer to the above definition, for example, ≤20, further for example, ≤10, etc.

[0179] Taking n=10 as an example, the regeneration method includes the following steps:

[0180] performing a first degradation treatment on the first degradable polymer material in the presence of the organic non-metallic catalyst and the aqueous solvent to obtain a first degradation product;

[0181] mixing the first degradation product and the second degradable polymer material, performing a second degradation treatment, and obtaining a second degradation product;

[0182] Repeat the step of "degrading the degradation product and the added new degradable polymer material" 8 times, end the degradation treatment, and obtain the 10th degradation product. The average polymerization degree of the 10th degradation product can refer to the above definition, for example, ≤20, further for example ≤10, etc.

[0183] In some embodiments, in the regeneration method, the temperature of any degradation treatment is independently 25°C to 200°C, further 50°C to 200°C, and further 125°C to 200°C.

[0184] In some embodiments, in the regeneration method, the temperature of any degradation treatment is independently 125°C to 200°C, further 130°C to 200°C, and even further 140°C to 180°C. It can also be selected from any one or two of the following temperature ranges: 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, etc. A more appropriate reaction temperature is beneficial for improving the degradation efficiency of the degradable polymer material. If the reaction temperature is too high, it may cause rapid evaporation of water in the system, which not only loses the reaction raw materials, but also makes the operation dangerous and places higher requirements on the reaction equipment. If the reaction temperature is too low, the reaction rate may be slow, and the degradation of the degradable polymer material into oligomers and / or monomers may take a long time, increasing time cost and energy consumption.

[0185] In the present application, the temperature of the degradation treatment can be the actual temperature of the reaction system, or the ambient temperature of the reaction system, such as the water bath temperature, oil bath temperature, etc.

[0186] In some embodiments, in the regeneration treatment method, the time of any degradation treatment is independently 0.1h to 5h, optionally 0.25h to 5h, further 0.5h to 4h, further 1h to 4h, further 1.5h to 4h, or selected from the following time intervals or any two time intervals: 0.1h, 0.25h, 0.5h, 0.75h, 1h, 1.2h, 1.4h, 1.6h, 1.8h, The reaction time can be selected from any one of the following time periods or any two of the following time periods: 0.25h, 0.5h, 0.75h, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h. A more appropriate reaction time is conducive to more efficient acquisition of the target product. If the reaction time is too long, it may increase time cost and energy consumption; if the reaction time is too short, the degradation product may not meet the requirements for recycling.

[0187] In some embodiments, in the regeneration method, the temperature of any degradation treatment is independently 125° C. to 200° C., and the time of any degradation treatment is independently 0.1 h to 5 h, optionally 0.25 h to 5 h.

[0188] In some embodiments, in the regeneration method, the temperature of any degradation treatment is independently 130° C. to 200° C., and the time of any degradation treatment is independently 1 hour to 4 hours.

[0189] In some embodiments, in the regeneration method, the temperature of any degradation treatment is independently 140° C. to 180° C., and the time of any degradation treatment is independently 1.5 h to 4 h.

[0190] In some embodiments, in the regeneration method, the pressure of any degradation treatment can independently be 1 atm-100 atm, or can be selected from any one or two of the following pressure ranges: 1 atm, 10 atm, 20 atm, 30 atm, 40 atm, 50 atm, 60 atm, 70 atm, 80 atm, 90 atm, 100 atm, etc.

[0191] In some embodiments, in the regeneration method, the pressure of any degradation treatment is independently 100±5 kPa. Alternatively, the pressure may be selected from any one or a range of any two of the following pressures: 95 kPa, 96 kPa, 97 kPa, 98 kPa, 100 kPa, 101 kPa, 102 kPa, 103 kPa, 104 kPa, 105 kPa, and the like. This regeneration process can be performed in a non-sealed environment and under non-high temperature and high pressure conditions, resulting in high catalytic degradation efficiency and rapid conversion of the degradable polymer into reusable oligomer and / or monomer raw materials. Adjusting the reaction pressure can affect the boiling point of the solvent and, consequently, the internal temperature of the system. Furthermore, it can also influence the intensity of molecular motion, all of which affect the reaction rate. If the reaction pressure is too high, the internal temperature of the system rises, molecular collisions become more intense, and the reaction becomes faster, but places higher demands on the equipment. If the reaction pressure is too low, the internal temperature of the system may be too low, the probability of molecular collisions may be reduced, and the probability of the reaction may be reduced, resulting in a slower reaction.

[0192] The degradation treatment of degradable polymer materials can be carried out under conditions without strong acids, strong bases and organic solvents, which helps to improve the problems of equipment corrosion and wastewater discharge in industrial applications.

[0193] In some embodiments, the regeneration method further comprises the following steps:

[0194] The degradation product is washed with an organic solvent, wherein the organic solvent is selected from one or more of chloroform, petroleum ether, carbon disulfide, ether, dichloromethane, benzene, toluene, and ethyl acetate. It is understood that the process of washing the degradation product with an organic solvent is also referred to as extraction treatment.

[0195] The degradation products after degradation treatment can be effectively separated from the organic non-metallic catalyst by simple washing (such as extraction). The separated degradation products can be directly used as raw materials for the polymerization process without concentration or re-purification, which is convenient for industrial production.

[0196] In some embodiments, the regeneration method comprises the following steps: adding a degradable polymer material, an organic non-metallic catalyst, and water to a reaction vessel, and carrying out a degradation reaction at 125°C to 200°C under dispersed conditions (e.g., under stirring conditions) (optionally, the degradation time can be as defined above, for example, 0.1h to 5h, and further 0.25h to 5h); further, the mass ratio of the organic non-metallic catalyst: water: degradable polymer material can be (0.001-0.1): (0.08-10): 1. In the regeneration method, the degradation reaction can be carried out in an atmospheric environment of 100±5kP. In some embodiments, the degradation reaction can be carried out in a pressure environment of 1atm-100atm.

[0197] In some embodiments, the regeneration method comprises the following steps: adding a degradable polymer material, an organic non-metallic catalyst and water to a reaction vessel, carrying out a degradation reaction at 125°C to 200°C under dispersed conditions (such as under stirring conditions) (optionally, the degradation time can be as defined above, for example, it can be 0.1h to 5h, and further can be 0.25h to 5h), cooling and washing with an organic solvent; further, the mass ratio of the organic non-metallic catalyst: water: degradable polymer material can be (0.001 to 0.1): (0.08 to 10): 1; further, the organic solvent can be any one of chloroform, petroleum ether, and dichloromethane, or any combination thereof, and further, the organic solvent can be any one of chloroform, petroleum ether, and dichloromethane. In the regeneration method, the degradation reaction can be carried out in an atmospheric environment of 100±5kP. In some embodiments, the degradation reaction can be carried out in a pressure environment of 1atm-100atm.

[0198] In some embodiments, the regeneration treatment method includes the following steps: adding a degradable polymer material, an organic non-metallic catalyst and water to a reaction vessel, carrying out a degradation reaction at 160±20°C under dispersed conditions (such as under stirring conditions) (optionally, the degradation time can be as defined above, for example, it can be 1.5±1h), cooling and washing with an organic solvent; further, the mass ratio of the organic non-metallic catalyst: water: degradable polymer material can be (0.035±0.02): (0.3±0.1): 1; further, the organic solvent can be any one of chloroform, petroleum ether, and dichloromethane. In the regeneration treatment method, the degradation reaction can be carried out in an atmospheric environment of 100±5kP. In some embodiments, the degradation reaction can be carried out in a pressure environment of 1atm-100atm.

[0199] In some embodiments, the regeneration treatment method includes the following steps: adding a degradable polymer material, an organic non-metallic catalyst and water to a reaction vessel, carrying out a degradation reaction at 160±10°C under dispersed conditions (such as under stirring conditions) (optionally, the degradation time can be as defined above, for example, it can be 1.5±0.5h), cooling and washing with an organic solvent; further, the mass ratio of organic non-metallic catalyst: water: degradable polymer material can be (0.035±0.005): (0.3±0.05): 1; further, the organic solvent can be any one of chloroform, petroleum ether, and dichloromethane. In the regeneration treatment method, the degradation reaction can be carried out in an atmospheric environment of 100±5kP. In some embodiments, the degradation reaction can be carried out in a pressure environment of 1atm-100atm.

[0200] In some embodiments, the regeneration method comprises the following steps: adding a degradable polymer material, an organic non-metallic catalyst, and water to a reaction vessel, carrying out a degradation reaction at 160±10°C under dispersed conditions (such as under stirring conditions) (optionally, the degradation time can be as defined above, for example, 1.5±0.5h), cooling, and washing with an organic solvent; further, the mass ratio of the organic non-metallic catalyst: water: degradable polymer material can be (0.0035±0.001): (0.15±0.05): 1; further, the organic solvent can be any one of chloroform, petroleum ether, and dichloromethane. In the regeneration method, the degradation reaction can be carried out in an atmospheric environment of 100±5kP. In some embodiments, the degradation reaction can be carried out in a pressure environment of 1atm-100atm.

[0201] The second aspect of the present application provides a low molecular weight composition, wherein the low molecular weight composition is a degradation product of a degradable polymer material, and the low molecular weight composition can be prepared according to the regeneration method described in the first aspect.

[0202] In some embodiments, the low molecular weight composition is the low molecular weight product of the first aspect.

[0203] In some embodiments, the average degree of polymerization of the low molecular weight composition is ≤20, further ≤15, and further ≤10. The average degree of polymerization of the low molecular weight composition can also be selected from any one of the following average degree of polymerization values ​​or an interval consisting of any two average degree of polymerization values: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc. The average degree of polymerization of the degradation product can also be selected from any one of the following ranges, for example, 1-20, 1-15, 1-10, 2-20, 2-15, 2-12, 2-10, etc.

[0204] The low molecular weight composition can be obtained by hydrolyzing a degradable polymer material (a discarded degradable polymer material can be used) with a catalyst. The product purification method is simple, the process is economical, and has good cost advantages.

[0205] The third aspect of the present application provides a method for recycling degradable polymer materials.

[0206] In some embodiments, the recycling method includes the following steps: performing a polymerization reaction using a low molecular weight composition as an initial raw material; wherein the low molecular weight composition is a degradation product prepared by the regeneration method described in the first aspect or the low molecular weight composition described in the second aspect.

[0207] Using a low-molecular-weight composition obtained by degrading a degradable polymer (which can be discarded), as a raw material, a polymerization reaction can be carried out under the catalysis of a conventional catalyst to obtain the polymer material again, thus achieving secondary use, or recycling, of the degraded polymer material. This recycling method is not only cost-effective but also environmentally friendly.

[0208] In some embodiments, the method for recycling a degradable polymer material comprises the following steps: S100: degrading the degradable polymer material in a system in the presence of an organic non-metallic catalyst and an aqueous solvent, and obtaining a degradation product system containing degradation products after the reaction is completed;

[0209] S200: directly using the degradation product system as a raw material for a synthesis reaction.

[0210] For step S100 , please refer to the first aspect of this application.

[0211] The synthesis reaction in step S200 is not particularly limited as long as the degradation product in step S100 participates in the reaction.

[0212] In some embodiments, in step S200, the degradation product system is directly used as a raw material to synthesize lactide. In this case, the molecular weight or degree of polymerization requirements of the degradation products in the degradation product system can be as described above. For example, the average degree of polymerization of the degradation products in the degradation product system can be ≤8, and further, the average degree of polymerization can be ≤5. For another example, the weight ratio or molar ratio of the monomer-like oligomers in the degradation products can be increased, for example, by controlling the weight ratio or molar ratio of the monomer-like oligomers in the degradation products to be greater than or equal to a certain value, such as ≥50%, ≥80%, ≥90%, etc.

[0213] In some embodiments, in step S200, the degradation product system is directly used as a raw material in a polymerization reaction to prepare a homopolymer or a copolymer.

[0214] The organic non-metallic catalyst used in this application can be separated from the degradation products through a simple separation step. Furthermore, depending on the requirements of subsequent polymerization reactions or other processing methods, the degradation products can be used directly in the next step without separating them from the organic non-metallic catalyst. For example, if the degradation product system obtained from the degradation of polylactic acid (PL) is used to produce lactide monomer using the organic non-metallic catalyst diphenyl phosphate (DPP), since vacuum distillation is typically performed during the lactide production process, the degradation products in the degradation product system can be separated from the organic non-metallic catalyst diphenyl phosphate (DPP) during the lactide production process. In this case, no additional separation steps are required for the degradation product system beforehand. A catalyst for lactide synthesis can be directly added to the system. During the reaction process of catalyzing the degradation product to produce lactide, the generated lactide can be transferred to a container for receiving the lactide product or to the next step of the reaction process, thereby being separated from the components of the degradation product system and the catalyst used for lactide synthesis.

[0215] A fourth aspect of the present application provides an application of an organic non-metallic catalyst in the degradation treatment of a degradable polymer material;

[0216] Wherein, the organic non-metallic catalyst and the degradable polymer material are as defined in the first aspect of the present application.

[0217] Using an organic non-metallic catalyst, polyester / polycarbonate materials (such as waste polyester / polycarbonate materials) can be converted into high-value-added products under mild conditions. The resulting products, after simple impurity removal, yield oligomers and / or monomers corresponding to the degradable polyester / polycarbonate materials, which can be reused in the polymerization process, thus enabling the recycling of plastics. The resulting monomer aqueous solution is of comparable quality to commercially available products and, after extraction to remove the catalyst, can be used for conventional applications.

[0218] It is understandable that the technical solution in this application can be used to degrade polyester / polycarbonate materials (such as discarded polyester / polycarbonate materials) into low molecular weight degradation products (such as oligomers and / or monomers), and the degradation products can also be used in the next synthesis process or utilization. For example, using polylactic acid as a polymer material (raw material), the technical solution disclosed in this application is used to extract and remove impurities from the degradation product (such as lactic acid monomer aqueous solution) that has undergone degradation treatment to obtain lactic acid monomer. Lactic acid is a platform molecule with a wide range of uses. In addition to preparing polylactic acid, it can also be used in various industries such as chemical industry, food, cosmetics, and pharmaceuticals. Taking the chemical industry as an example, lactic acid can be used to prepare a variety of commodities and intermediate chemicals, such as lactate, 1,2-propylene glycol, acrylic acid, pyruvic acid, acetaldehyde, 2,3-pentanedione, etc. In addition, lactic acid can be used as an antifreeze agent, a fixing agent for wool fabric printing, and can also be used for softening leather, descaling, cleaning, adjusting pH, etc. It is also a green organic solvent. Some examples are provided below.

[0219] In order to better understand the present application, the present application is further explained through the following examples, but it should not be understood as a limitation of the present application. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the scope of protection of the present application.

[0220] For experimental methods in the following examples where detailed conditions are not specified, reference is made to the guidance given in this application, and may also be based on experimental manuals or conventional conditions in the field, or the conditions recommended by the manufacturer, or reference may be made to experimental methods known in the art.

[0221] Unless otherwise specified, the raw materials used in the following experiments can be purchased from the market.

[0222] The following examples are not particularly limited. The performance test methods and evaluation criteria in this application are as follows:

[0223] Number average molecular weight (M n ), weight average molecular weight (M w) and polydispersity index (PDI) test method: Gel permeation chromatography (1260, Agilent) was used to test the sample at a concentration of 10 mg / mL dissolved in tetrahydrofuran (THF) at 35°C. The mobile phase was tetrahydrofuran at a flow rate of 1.0 mL / min. The standard sample was narrowly distributed polystyrene (PS). The lower limit of the gel permeation chromatography test was 550 Da-600 Da. According to the sample 1 The number average molecular weight (M) of the sample can be calculated from the H NMR spectrum. n ), average degree of polymerization The detailed testing method is as follows: Lactic acid and / or its oligomers were dissolved in DMSO-d6 at a concentration of 100 mg / mL and analyzed at 25°C using a Fourier transform nuclear magnetic resonance spectrometer (400 MHz, AVANCE III HD, Bruker). A small amount of D2O was added to the test sample. Other compounds were dissolved in CDCl3 at a concentration of 10 mg / mL.

[0224] Example 1

[0225] 2.5g of PLA (a biodegradable polymer), 0.0875g of DPP (an organic non-metallic catalyst), and 0.75g of deionized water (equivalent to an aqueous solvent) were added to a reaction tube. The mixture was stirred magnetically and allowed to react in an oil bath at 160°C (ambient temperature) for 1.5 hours under atmospheric pressure. After cooling, the mixture was washed with chloroform (an organic solvent). Calculations indicate that the mass ratio of organic non-metallic catalyst: water: biodegradable polymer is 0.035:0.3:1.

[0226] The polylactic acid model used in Example 1 is LX175 (TotalEnergies Corbion), the number average molecular weight (M) of the PLA used was measured by gel permeation chromatography n ), weight average molecular weight (M w ) and polydispersity index (PDI) were 121.0 kDa, 199.7 kDa and 1.65, respectively; the catalyst used was diphenyl phosphate DPP.

[0227] The molecular weight of the degradation product was lower than the detection limit of GPC, indicating that its molecular weight was lower than 600Da. The average molecular weight of the degradation product was 191Da and the average degree of polymerization was 100Da. The product after chloroform extraction is 2.4, of which 90.4% is converted into water-soluble small molecules. 1The H NMR spectra are shown in Figure 1. The methyl peak shifts vary depending on the chemical environment. The peak at 1.23 ppm corresponds to the methyl group (OHCOCH(CH3)OH) in the lactic acid monomer (position labeled a in Figure 1), the peak at 1.27 ppm corresponds to the methyl group (-COCH(CH3)OH) near the hydroxyl end of the lactic acid oligomer (position labeled c in Figure 1), and the peaks at 1.38-1.50 ppm correspond to the other methyl groups (-COCH(CH3)O-) in the lactic acid oligomer (position labeled f in Figure 1). Peaks corresponding to methine groups in the lactic acid monomer and its oligomers are at 4.03-5.50 ppm (positions labeled b, d, and e in Figure 1), which overlap with the water peak. Peaks at 7.0-7.4 ppm correspond to the characteristic benzene ring peaks of DPP (positions labeled i, h, and g in Figure 1). Aside from the characteristic peak at 2.5 ppm corresponding to the solvent DMSO-d6, no other significant signals are observed. The calculation method for the molar percentage of monomers in the degradation product and the conversion rate of polymers into water-soluble small molecules is as described above. Taking Example 1 as an example, the calculation method is as follows: the integral value of the characteristic peak corresponding to the terminal methyl group of lactic acid oligomer at 1.27 ppm is set to 1, the integral value of the characteristic peak at 1.23 ppm is 1.15, and the integral value of the characteristic peak at 1.38-1.50 ppm is 3.01. The calculation results show that the number average molecular weight of the degradation product is (90+72*3.01 / (1+1.15)≈191), the molar percentage of lactic acid monomers in the degradation product is 1.15 / (1+1.15)≈0.535; the remaining water-insoluble solid residue is 0.2406 g, and the conversion rate of polymers into water-soluble small molecules is (1-0.2406 / 2.5≈0.904).

[0228] In this application, unless otherwise specified, the degradation product obtained by regenerating the degradable polymer material (in the presence of an organic non-metallic catalyst and water) using gel permeation chromatography is tested, and the measured molecular weight is lower than the GPC detection limit, which means that the molecular weight of the polymer material contained in the obtained degradation product is lower than 600Da.

[0229] Example 2

[0230] The raw materials and degradation process in Example 2 were essentially the same as in Example 1, except that the amount of the organic non-metallic catalyst used was 0.025 g, and petroleum ether was used as the organic solvent for washing the degradation products. Calculations indicate that the mass ratio of organic non-metallic catalyst: water: degradable polymer material is 0.01:0.3:1.

[0231] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 387 Da, the average degree of polymerization was 5.1, and the conversion rate was 40.0%.

[0232] Example 3

[0233] The raw materials and degradation process in Example 3 were essentially the same as in Example 1, except that the amount of the organic non-metallic catalyst used was 0.05 g, and dichloromethane was used as the organic solvent for washing the degradation products. Calculations indicate that the mass ratio of organic non-metallic catalyst: water: degradable polymer material is 0.02:0.3:1.

[0234] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 289 Da, the average degree of polymerization was 3.8, and the conversion rate was 61.6%.

[0235] Example 4

[0236] The raw materials and degradation process in Example 4 were essentially the same as in Example 1, except that 0.125 g of the organic non-metallic catalyst was used, and ether was used as the organic solvent for washing the degradation products. Calculations indicate that the mass ratio of organic non-metallic catalyst: water: degradable polymer material is 0.05:0.3:1.

[0237] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 185 Da, the average degree of polymerization was 2.3, and the conversion rate was 99.2%.

[0238] Examples 5 to 9

[0239] The raw materials and degradation processes of Examples 5 to 9 are basically the same as those of Example 1, except that the ambient temperatures of the degradation treatment are different, namely 120° C., 140° C., 150° C., 170° C. and 180° C.

[0240] The washed degradation products were tested using the same method as in Example 1. The molecular weight of the degradation products was lower than the GPC detection limit. The conversion rate of the degradation products and the average molecular weight and average degree of polymerization calculated by the measured H NMR spectrum are shown in Table 1.

[0241] Table 1 Test results of degradation products after washing in Examples 5 to 9

[0242] Examples 10 to 13

[0243] The raw materials and degradation treatment processes of Examples 10 to 13 are basically the same as those of Example 1, except that the degradation treatment time is different, namely 0.5 h, 1 h, 2 h and 2.5 h, respectively.

[0244] The washed degradation products were tested using the same method as in Example 1. The molecular weight of the degradation products was lower than the detection limit of GPC. The conversion rate of the degradation products and the average molecular weight, average degree of polymerization, and conversion rate calculated by the measured H NMR spectrum are shown in Table 2.

[0245] Table 2 Test results of degradation products after washing in Examples 10 to 13

[0246] Example 14

[0247] 2.5 g of polylactic acid PLA (equivalent to the first degradable polymer material), 0.0875 g of diphenyl phosphate DPP, and 0.75 g of deionized water were added to a reaction tube, stirred with a magnetic stirrer and vented to the atmosphere, and reacted in an oil bath at 160° C. for 1.5 h (equivalent to the first degradation treatment). The average molecular weight of the obtained product (equivalent to the first degradation product) was calculated to be 191 Da based on the measured nuclear magnetic resonance hydrogen spectrum. 2.5 g of PLA (equivalent to the second degradable polymer material) and 0.35 g of deionized water were added again, and the reaction was continued for 1.5 h (equivalent to the second degradation treatment). The average molecular weight of the degradation product (equivalent to the second degradation product) was calculated based on the measured nuclear magnetic resonance hydrogen spectrum to be 181 Da. The PLA raw material was added repeatedly for 8 degradation steps (equivalent to the 3rd to 10th degradation treatments), and the average molecular weight of the final degradation product (equivalent to the 10th degradation product) was calculated based on the measured nuclear magnetic resonance hydrogen spectrum to be 193Da. Among them, a total of 25g of PLA was added (equivalent to the sum of the masses of the 1st to 10th degradable polymer materials), and water was also added in the 3rd to 10th degradation treatments. The mass ratio of the added water to the degradable polymer material remained the same as that of the second time.

[0248] Example 15

[0249] 1000 g of polylactic acid PLA (equivalent to the first degradable polymer material), 35 g of diphenyl phosphate DPP, and 83 g of deionized water were added to a normal pressure reactor, mechanically stirred, and reacted in an oil bath at 160° C. for 1.5 h (equivalent to the first degradation treatment). The average molecular weight of the obtained degradation product (equivalent to the first degradation product) was calculated based on the measured nuclear magnetic resonance hydrogen spectrum to be 347 Da. 1000g of polylactic acid PLA (equivalent to the second degradable polymer material) and 83g of deionized water were added again, and the reaction was continued for 1.5h (equivalent to the second degradation treatment). The average molecular weight of the degradation product (equivalent to the second degradation product) was calculated based on the measured nuclear magnetic resonance hydrogen spectrum to be 284Da. Repeat 2 times (equivalent to the 3rd and 4th degradation treatments), and the average molecular weight of the final product (equivalent to the 4th degradation product) is calculated based on the measured nuclear magnetic resonance hydrogen spectrum to be 287Da Among them, a total of 4000g of PLA was added (equivalent to the sum of the masses of the 1st to 4th degradable polymer materials), and water was also added in the 3rd and 4th degradation treatments. The mass ratio of the added water to the degradable polymer material remained the same as that of the 1st and 2nd times.

[0250] 100 g of degradation product was placed in a two-necked flask, 0.75 g of ZnO was added as a catalyst, and the temperature was gradually increased from 180 ° C to 230 ° C. The crude lactide product was obtained by vacuum distillation. After washing with water and purification by recrystallization from ethyl acetate, the PLA product (M) was obtained by ring-opening polymerization of lactide under the action of a conventional industrial catalyst Sn(Oct)2. n =390,600,M w =505,300), realizing the closed-loop recycling of PLA.

[0251] Example 16

[0252] The raw materials and degradation process of Example 16 are basically the same as those of Example 1, except that the catalyst used is bis(4-nitrophenyl) phosphate (BNPP for short).

[0253] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 182 Da, the average degree of polymerization was 2.3, and the conversion rate was 84.6%.

[0254] Example 17

[0255] The raw materials and degradation treatment process of Example 17 are basically the same as those of Example 1, except that the catalyst used is bis(4-fluorophenyl) phosphate (BFPP for short), and the degradation treatment time is 0.5 h.

[0256] The washed degradation product was tested using the same method as in Example 1. The molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 354 Da, the average degree of polymerization was 4.7, and the conversion rate was 67.4%.

[0257] Example 18

[0258] The raw materials and degradation treatment process of Example 18 are basically the same as those of Example 1, except that the catalyst used is bis(4-trifluoromethylphenyl)phosphate (BTFPP for short), and the degradation treatment time is 0.5 h.

[0259] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 343 Da, the average degree of polymerization was 4.5, and the conversion rate was 69.2%.

[0260] Example 19

[0261] The raw materials and degradation treatment process of Example 19 are basically the same as those of Example 1, except that the catalyst used is binaphthol phosphate (abbreviated as BNDHP) and the degradation treatment time is 4 hours.

[0262] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 243 Da, the average degree of polymerization was 3.1, and the conversion rate was 73.8%.

[0263] Example 20

[0264] The raw materials and degradation process of Example 20 are basically the same as those of Example 1, except that the catalyst used is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU for short), the degradation treatment time is 3 h, and the organic solvent used to wash the degradation product is petroleum ether.

[0265] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 333 Da, the average degree of polymerization was 4.4, and the conversion rate was 68.0%.

[0266] Example 21

[0267] The raw materials and degradation process of Example 21 are basically the same as those of Example 1, except that the catalyst used is 1,5,7-triazidobicyclo[4.4.0]dec-5-ene (TBD for short), and the degradation treatment time is 4 hours.

[0268] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 249 Da, the average degree of polymerization was 3.2, and the conversion rate was 73.0%.

[0269] Example 22

[0270] The raw materials and degradation treatment process of Example 22 are basically the same as those of Example 1, except that the degradable polymer material used is polycaprolactone (abbreviated as PCL), the degradation treatment time is 3 hours, and the organic solvent used to wash the degradation product is dichloromethane.

[0271] Polycaprolactone model 6800 (Perstorp Company), the number average molecular weight (M n ), weight average molecular weight (M w ) and polydispersity index (PDI) were 65.2 kDa, 213.1 kDa and 3.27, respectively.

[0272] The washed degradation product was tested using the same method as in Example 1, and the molecular weight thereof was lower than the GPC detection limit.

[0273] Example 23

[0274] The raw materials and degradation process of Example 23 are basically the same as those of Example 1, except that the degradable polymer material used is polylactic acid-glycolic acid copolymer (PLGA for short), and the degradation treatment time is 2.5 hours.

[0275] Poly(lactic acid-co-glycolic acid) copolymer was prepared in the laboratory, and the number average molecular weight (M n ), weight average molecular weight (M w ) and polydispersity index (PDI) were 9.97 kDa, 15.0 kDa and 1.50, respectively.

[0276] The washed degradation product was tested using the same method as in Example 1, and the molecular weight thereof was lower than the GPC detection limit.

[0277] Example 24

[0278] The raw materials and degradation treatment process of Example 24 are basically the same as those of Example 1, except that the degradable polymer material used is polybutylene adipate / terephthalate (PBAT for short), and the degradation treatment time is 2.5 hours.

[0279] Polybutylene adipate / terephthalate model is F Blend C1200 (BASF SE), the number average molecular weight (M n ), weight average molecular weight (M w ) and polydispersity index (PDI) were 17.3 kDa, 31.0 kDa and 1.79, respectively.

[0280] The washed degradation product was tested using the same method as in Example 1, and the molecular weight thereof was lower than the GPC detection limit.

[0281] Example 25

[0282] The raw materials and degradation process in Example 25 were essentially the same as those in Example 1, except that the amount of the organic non-metallic catalyst used was 0.125 g, the degradable polymer used was poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB), the degradation time was 3 hours, and the organic solvent used to wash the degradation products was dichloromethane. Calculations indicate that the mass ratio of organic non-metallic catalyst: water: degradable polymer is 0.05:0.3:1.

[0283] The model of poly (3-hydroxybutyrate-co-4-hydroxybutyrate) is EM 10080 (ECOMRNN). The number average molecular weight (M) of the P34HB used was measured by gel permeation chromatography. n ), weight average molecular weight (M w ) and polydispersity index (PDI) were 128.9 kDa, 228.6 kDa and 1.77, respectively, and the testing conditions were the same as in Example 1.

[0284] The washed degradation product was tested using the same method as in Example 1, and the molecular weight thereof was lower than the GPC detection limit.

[0285] Example 26

[0286] The raw materials and degradation process in Example 26 were essentially the same as in Example 1, except that the amount of the organic non-metallic catalyst used was 0.125 g, the biodegradable polymer used was polybutylene succinate (PBS), the degradation treatment time was 4 hours, and the organic solvent used to wash the degradation products was dichloromethane. Calculations indicate that the mass ratio of organic non-metallic catalyst: water: biodegradable polymer is 0.05:0.3:1.

[0287] The model of polybutylene succinate was BioPBSTM FD72PM (Public Company Limited). The number average molecular weight (M n ), weight average molecular weight (M w ) and polydispersity index (PDI) were 25.2 kDa, 43.2 kDa and 1.71, respectively.

[0288] The washed degradation product was tested using the same method as in Example 1, and the molecular weight thereof was lower than the GPC detection limit.

[0289] Example 27

[0290] The raw materials and degradation treatment process of Example 27 are basically the same as those of Example 1, except that the degradable polymer material used is a 3D printing material.

[0291] 3D printing materials were purchased from online retail platforms (Taobao.com), and the number average molecular weight (M n ), weight average molecular weight (M w ) and polydispersity index (PDI) were 10.9 kDa, 18.4 kDa and 1.69, respectively.

[0292] The washed degradation product was tested using the same method as in Example 1. The molecular weight was lower than the GPC detection limit. The average molecular weight was calculated from the measured H NMR spectrum to be 193 Da, the average degree of polymerization was 2.4, and the conversion rate was 78.2%.

[0293] Example 28

[0294] The raw materials and degradation process in Example 28 were essentially the same as in Example 1, except that 0.125 g of the organic non-metallic catalyst was used, the degradable polymer used was a plastic straw (primarily composed of polylactic acid and polybutylene succinate), the degradation time was 4 hours, and dichloromethane was used as the organic solvent for washing the degradation products. Calculations indicate that the mass ratio of organic non-metallic catalyst: water: degradable polymer is 0.05:0.3:1.

[0295] Plastic straws were purchased from an online retail platform (Taobao.com), and the number average molecular weight (M n ), weight average molecular weight (M w ) and polydispersity index (PDI) coefficients were 122.3 kDa, 166.6 kDa and 1.36, respectively.

[0296] The washed degradation product was tested using the same method as in Example 1, and the molecular weight thereof was lower than the GPC detection limit.

[0297] Example 29

[0298] The raw materials and degradation treatment process of Example 29 are basically the same as those of Example 1, except that the degradable polymer material used is polytrimethylene carbonate (PTMC for short), the organic solvent used to wash the degradation product is dichloromethane, and the degradation treatment time is 3 hours.

[0299] Polytrimethylene carbonate was made in the laboratory, and the number average molecular weight (M n ), weight average molecular weight (M w) and polydispersity index (PDI) were 23.6 kDa, 36.0 kDa and 1.53, respectively.

[0300] The washed degradation product was tested using the same method as in Example 1, and the molecular weight thereof was lower than the GPC detection limit.

[0301] Example 30

[0302] A recycling method for degradable polyester / polycarbonate materials:

[0303] 2.5 g of polylactic acid (PLA), 0.0875 g of diphenyl phosphate (DPP), and 0.75 g of deionized water were added to a reaction tube. The mixture was stirred with a magnetic stirrer and allowed to react in an oil bath at 160°C for 1.5 h. 2.5 g of deionized water was then added and the mixture was allowed to react for 1.5 h. After cooling, the mixture was washed with chloroform. The molecular weight of the product was lower than the detection limit of GPC and all of the product was converted into water-soluble small molecules. The average molecular weight of the degradation product was 108 as determined by nuclear magnetic resonance. 86.2 mol% of the total lactic acid monomer is lactic acid, which is similar to the commercially available 85% lactic acid aqueous solution (monomer proportion 86.0 mol%).

[0304] Example 31

[0305] The raw materials and degradation treatment process of Example 31 are basically the same as those of Example 1, except that the catalyst used is bis(4-nitrophenyl) phosphate (BNPP for short), and the degradation treatment time is 0.5 h.

[0306] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 215 Da, the average degree of polymerization was 2.7, and the conversion rate was 62.4%.

[0307] Example 32

[0308] The raw materials and degradation treatment process of Example 32 are basically the same as those of Example 1, except that the catalyst used is bis(4-nitrophenyl) phosphate (BNPP for short), and the degradation treatment time is 1 hour.

[0309] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 186 Da, the average degree of polymerization was 2.3, and the conversion rate was 85.8%.

[0310] Example 33

[0311] The raw materials and degradation treatment process of Example 33 are basically the same as those of Example 1, except that the catalyst used is binaphthol phosphate (abbreviated as BNDHP) and the degradation treatment time is 3.5 hours.

[0312] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 291 Da, the average degree of polymerization was 3.8, and the conversion rate was 74.3%.

[0313] Example 34

[0314] The raw materials and degradation treatment process of Example 34 are basically the same as those of Example 1, except that the catalyst used is R-binaphthol phosphate (abbreviated as R-BNDHP) and the degradation treatment time is 5 hours.

[0315] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 247 Da, the average degree of polymerization was 3.2, and the conversion rate was 70.8%.

[0316] Example 35

[0317] The raw materials and degradation treatment process of Example 35 are basically the same as those of Example 1, except that the catalyst used is bis(4-methylphenyl)phosphate (abbreviated as BMPP) and the degradation treatment time is 2.0 h.

[0318] The washed degradation product was tested using the same method as in Example 1. Its molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 270 Da, the average degree of polymerization was 3.5, and the conversion rate was 77.9%.

[0319] Example 36

[0320] The raw materials and degradation treatment process of Example 36 are basically the same as those of Example 1, except that the catalyst used is bis(4-methoxyphenyl) phosphate (BMOPP for short), and the degradation treatment time is 2.5 h.

[0321] The washed degradation product was tested using the same method as in Example 1. The molecular weight was lower than the GPC detection limit. The average molecular weight of the degradation product was calculated by hydrogen nuclear magnetic resonance spectrum to be 227 Da, the average degree of polymerization was 2.9, and the conversion rate was 80.2%.

[0322] The inventors of this application also conducted the following (1) to (5) groups of experiments:

[0323] (1) Polylactic acid (M) with a diameter of 8 mm n =121.0 kDa, M w =199.7 kDa) film discs (17 ± 1 mg) were placed in five different reaction environments and subjected to five experiments (denoted as A1, A2, A3, A4, and A5) at 70°C. Three parallel runs were performed for each experiment. The conversion rate was calculated on the first, second, third, fourth, and fifth days of each experiment, and the morphology of the residual polymer in the system was regularly observed.

[0324] (1) Experiment A1: The aforementioned polylactic acid film disc was placed in a diphenyl phosphate (DPP) aqueous solution (3.5 wt%, 10 mL, pH = 1). After one day of reaction, the polylactic acid film disc was observed to have broken. After two days, it was difficult to observe obvious insoluble matter in the system, and the polylactic acid film disc was basically converted into a water-soluble small molecule product (calculated conversion rate > 95%). Figure 2 shows optical photographs of the polylactic acid film residue of one of the three parallel experiments of Experiment A1 at 8 hours (8h), 16 hours (16h), 24 hours (24h), 32 hours (32h), 48 hours (48h) and 72 hours (72h) after the start of the reaction. The dotted line indicates that there is no solid residue. The conversion rate of this system reached 95.3% after two days of reaction and 100% after three days of reaction (the change in conversion rate can be seen in Figure 3 and Table 3).

[0325] (2) Test A2: The aforementioned polylactic acid film disc was placed in water. After 5 days of reaction, the conversion rate of this system was only 5.1% (see Figure 3 and Table 3 for the change in conversion rate). The reason why the degradation rate of the polylactic acid film disc in this system was significantly lower than that in Test A1 may be that no organic non-metallic catalyst was added. Even if water was present in the system, without the action of a catalyst, the degradation process was very slow.

[0326] (3) Test A3: The aforementioned polylactic acid film disc was placed in a dry environment, and 3.5 wt% diphenyl phosphate (DPP) was mixed into the polylactic acid film disc. The polylactic acid film disc mixed with 3.5 wt% DPP was prepared by adding DPP to a DCM solution containing PLA, and after the solvent evaporated, a sample film (M) containing uniformly distributed diphenyl phosphate (DPP) was obtained. n =84.3 kDa, M w=136.8 kDa), and the film was placed in a sealed glass container containing phosphorus pentoxide to minimize moisture in the environment. After 5 days of reaction, the conversion rate of this system was 11.9% (see Figure 3 and Table 3 for the change in conversion rate). The degradation rate of the PLA film disc in this system was significantly lower than that in Test A1 but slightly higher than that in Test A2. This may be because, although no additional water was added, there was a certain amount of water vapor in the atmosphere. When a certain amount of diphenyl phosphate (DPP) was mixed in, the degradation process of the PLA film disc continued, but at a slower rate.

[0327] (4) Test A4: The polylactic acid film disc was placed in a dilute hydrochloric acid solution (pH = 1). The conversion rate of this system was 10.4% after 5 days of reaction (the change in conversion rate can be seen in Figure 3 and Table 3).

[0328] (5) Test A5: The polylactic acid film disc was placed in a sodium hydroxide aqueous solution (pH = 13). After 5 days of reaction, the conversion rate of this system was 65.7% (see Figure 3 and Table 3 for the change in conversion rate).

[0329] Table 3 Conversion rate of polylactic acid film discs in the system from day 1 to day 5 into water-soluble small molecules in three parallel experiments of experiments A1 to A5

[0330] A comparison of Experiments A1 and A3 shows that diphenyl phosphate catalyzes the degradation of PLA primarily through hydrolysis. When the water content in the system is extremely low (only residual moisture in the raw materials and moisture in the environment), the degradation rate of PLA is greatly slowed. When the water in the system is basically exhausted, PLA basically does not degrade. However, in aqueous solvents, diphenyl phosphate can significantly catalyze the hydrolysis of PLA.

[0331] From the comparison of Test A1, Test A4 and Test A5, it can be seen that the effect of diphenyl phosphate catalyzing the hydrolysis of PLA is much better than that of traditional acid-base catalysts.

[0332] (II) Two groups of experiments were conducted on the degradation of polylactic acid. The only difference between the two groups of experiments was that one group of experiments did not add the catalyst diphenyl phosphate (experiment A7). The initial peak molecular weight (M) of the polylactic acid sample used was peak ) is 146.8 kDa (gel permeation chromatography test, tetrahydrofuran mobile phase, polystyrene as standard). When a sample is tested by gel permeation chromatography, the molecular weight corresponding to the top of the peak in the elution curve or molecular weight distribution curve is the peak molecular weight (M peak The peak molecular weight can be used to preliminarily determine the molecular weight of the polymer.

[0333] (6) Test A6: 0.5 g of polylactic acid (PLA) and 0.025 g of diphenyl phosphate (DPP) were placed in a test tube and placed in an oil bath at 160°C. The tube was left uncovered and 2 drops of deionized water were added every 5 minutes during the reaction. The test lasted for 0.5 h.

[0334] (7) Test A7: 0.5 g of polylactic acid was placed in a test tube, and the tube was exposed to the air in an oil bath at 160°C. During the reaction, 2 drops of deionized water were added every 5 minutes. The test time was 0.5 h.

[0335] After the reaction started, samples were taken every 5 minutes for testing using the same testing method as above (gel permeation chromatography, tetrahydrofuran as mobile phase, polystyrene as standard); the peak molecular weight (M) of the products obtained by tests A6 and A7 after 0.5 hours was measured. peak ) are 0.5 kDa and 83.7 kDa, respectively. Experiments A6 and A7 show that even when a small amount of water is added, diphenyl phosphate can still effectively catalyze the degradation of polylactic acid (see Figure 4).

[0336] (3) 1 g of each of LX175 PLA pellets (diameter ~3 mm) purchased from TotalEnergies Corbion was placed in five different solutions containing 0.035 g of diphenyl phosphate (DPP) (solution mass: 20 g) at an ambient temperature of 80°C. After 2 days, all components were lyophilized and subjected to GPC analysis.

[0337] (1) Test B1: Deionized water, GPC test results of freeze-dried sample after 2 days: M n =6.3 kDa, M w =9.1 kDa, PDI = 1.44;

[0338] (2) Test B2: Methanol, GPC test results of freeze-dried sample after 2 days: M n =26.7 kDa, M w =33.1 kDa, PDI = 1.24;

[0339] (3) Test B3: Methanol / water mixed solvent (m / m = 1:3), GPC test results of freeze-dried sample after 2 days: M n =7.4 kDa, M w =10.7 kDa, PDI =1.45; where m / m represents the mass ratio of the two components;

[0340] (4) Test B4: Methanol / tetrahydrofuran mixed solvent (m / m = 1:3), GPC test results of freeze-dried sample after 2 days: M n =8.6 kDa, M w =13.5 kDa, PDI = 1.57;

[0341] (5) Test B5: Water / tetrahydrofuran mixed solvent (m / m = 1:3), GPC test results of freeze-dried sample after 2 days: M n =0.5 kDa, M w =0.7 kDa, PDI =1.4, the molecular weight of the sample is close to the lower limit of GPC detection.

[0342] Experiment B1 shows that polylactic acid degrades rapidly in the presence of only water and diphenyl phosphate. A comparison of Experiments B1, B2, and B3 shows that polylactic acid degrades faster in a water-based system than in a methanol-based system; the degradation rate in the water-based system is similar to that in a methanol-water mixed solvent system. Comparisons of Experiments B1 and B5, as well as Experiments B2 and B4, show that the addition of tetrahydrofuran accelerates the degradation of polylactic acid. This is likely due to the tetrahydrofuran's solubilizing effect, which evenly distributes the raw materials throughout the system, increasing their contact and reaction opportunities and thus accelerating the reaction process.

[0343] (4) Degradation tests using different polymer materials as substrates.

[0344] 15 g each of three brands of PLA pellets (all purchased from TotalEnergies Corbion, with brand names LX175, LX530, and L105), 10 g each of fragments of two PLA products (purchased from an online retail platform (Taobao)), and 10 g each of three common mechanically recyclable durable plastics (polyethylene terephthalate PET, polypropylene PP, and polyethylene PE) (purchased from an online retail platform (Taobao)) were mixed. The mixed plastics included one polyethylene terephthalate PET, one polypropylene PP, one polyethylene PE, and five polylactic acid PLAs (Figure 5A). 2.275 g of diphenyl phosphate DPP (with a mass ratio of 0.035 to polylactic acid PLA) and 8 g of water were added to the above-mentioned mixed plastic system, and the reaction was terminated after reacting at 160°C for 1.5 h. The solid matter insoluble in the reaction system in the reaction product was separated from the flowable substance, and the separated flowable substance (the substance contained in the container shown in B of Figure 5) was the degradation product.

[0345] The degradation product (substance shown in B of FIG5 ) was subjected to 1H NMR characterization revealed that the degradation products were lactic acid oligomers and / or monomers, with an average molecular weight of 220 Da and an average degree of polymerization of 2.8. Polymers such as PET, PP, and PE, as well as their corresponding oligomers and / or monomers, were not found in the degradation products. Figure 5 (C) shows the separated solids. DSC analysis of the different plastics was performed and compared with the DSC results of the corresponding raw materials (PET, PP, and PE sheets or pellets) before degradation treatment, resulting in Figures 5 (D, E, and F).

[0346] Through DSC characterization, it can be seen that the melting points (T m ) remained basically unchanged: the melting point of PET was 247.7°C before treatment and 248.1°C after treatment (D in FIG5 ); the melting point of PP was 161.3°C before treatment and 162.0°C after treatment (E in FIG5 ); the melting point of PE was 129.5°C before treatment and 129.6°C after treatment (F in FIG5 ),

[0347] Through the degradation test on mixed plastics, it can be seen that when the mixed plastics containing traditional durable plastics and polylactic acid are treated under the aforementioned conditions (that is, in the presence of water and a specific organic non-metallic catalyst, such as DPP), not only the degradation of the degradable polymer materials such as polylactic acid is not affected, but also the traditional durable plastics such as PET, PP and PE are not affected by the treatment (the apparent morphology of PET, PP and PE does not show obvious changes (see the comparison between A and C in Figure 5) and the melting point does not change significantly (see D, E and F in Figure 5)) and the original performance is better maintained. In the future, the traditional durable plastics PET, PP and PE can be further mechanically recycled to obtain corresponding recyclables of better quality.

[0348] DSC testing method: The thermal properties of plastics are characterized using a differential scanning calorimeter (Q2000, TA Instruments). For PET, a weighed sample is placed in a sample pan and heated to 320°C under a nitrogen atmosphere. The sample is allowed to equilibrate for 5 minutes to remove thermal history. The sample is then cooled to 20°C at a rate of 10°C / min. After equilibration for 5 minutes, the temperature is then raised to 320°C at the same rate and the data recorded. For PP and PE, the temperature is raised to 220°C.

[0349] (5) PLA pellets (diameter ∼3 mm) of LX175 purchased from TotalEnergies Corbion were placed in 5 g of the following three different aqueous solutions (5 g of solution mass) at an ambient temperature of 80°C. 50 mg of the solution was lyophilized 1 day and 3 days after the start of the reaction. 1 H NMR test.

[0350] (1) The first aqueous solution was a 0.1 M (mol / L) HCl solution. Almost no water-soluble substances were detected. Three days after the reaction began, the system became a suspension with a milky white color.

[0351] (2) The second aqueous solution was an aqueous solution containing 5 wt% diphenyl phosphate (DPP). One day after the reaction began, the solution contained lactic acid oligomers and monomers with an average molecular weight of 385 and an average degree of polymerization of 5.1. Three days after the reaction began, the average molecular weight of the degradation product was 108 and the average degree of polymerization was 1.3. At this time, the solution was clear and transparent.

[0352] (3) The third aqueous solution was a 0.1 M (mol / L) HCl solution containing 5 wt% diphenyl phosphate (DPP). One day after the reaction began, the solution was found to contain lactic acid oligomers and monomers with an average molecular weight of 167 and an average degree of polymerization of 2.1. Three days after the reaction began, the solution became clear and transparent, and the average molecular weight of the degradation product was 106 and the average degree of polymerization was 1.3.

[0353] Experimental results of polylactic acid (PL) in three different aqueous solutions revealed that, on the one hand, HCl alone was ineffective in catalyzing the degradation of PLA. On the other hand, PLA was able to degrade relatively rapidly in the presence of water and the organic non-metallic catalyst diphenyl phosphate (DPP). While the addition of additional hydrochloric acid accelerated degradation somewhat in the early stages of the reaction, the molecular weight and average degree of polymerization of the resulting degradation products remained largely unchanged. Therefore, PLA can be rapidly degraded in the presence of water and an organic non-metallic catalyst such as diphenyl phosphate (DPP) without the presence of hydrochloric acid, enabling better recycling.

[0354] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

[0355] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0356] The above-described embodiments merely represent several implementation methods of the present application, and although the descriptions thereof are relatively detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the concept of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the patent application shall be based on the appended claims, and the specification may be used to interpret the content of the claims.

Claims

1. A method for regenerating a degradable polymer material, comprising the following steps: In a system where an organic non-metallic catalyst and a water-containing solvent exist, a degradable polymer material is degraded to obtain a degradation product; in, The degradable polymer material includes one or more of polyester material and polycarbonate material; The organic non-metal catalyst is selected from one or more of diphenyl phosphate, binaphthol phosphate and organic bases, and the organic base is selected from one or more of nitrogen-containing heterobicyclic bases, 4-dimethylaminopyridine and phosphazene base compounds.

2. The regeneration method according to claim 1, wherein: The diphenyl phosphate has a structure shown in formula (I): In formula (I), R 11 , R 12 , R 13 , R 14 , R 15 , R 21 , R 22 , R 23 , R 24 and R 25 Each independently selected from any one of -H, halogen, -NO2, -CN, C1-C4 alkoxy, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of -NO2, -CN, halogen, and C1-C4 alkyl; The binaphthol phosphate has a structure shown in formula (II): In formula (II), R3 and R3' are each independently selected from -H, -SiPh3 or Wherein, "*" indicates the attachment site of a covalent single bond; R 41 , R 42 , R 43 , R 44 and R 45 Each is independently selected from any one of -H, halogen, -NO2, -CN, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen, -NO2, -CN, phenyl, and C1-C4 alkyl; or R 41 , R 42 , R 43 , R 44 and R 45 At least two of them form a ring and participate in forming a fused ring, R 41 , R 42 , R 43 , R 44 and R 45 The uncyclic groups are each independently selected from any one of -H, halogen, -NO2, -CN, C1-C6 alkyl, halogen-substituted C1-C6 alkyl, phenyl, and substituted phenyl, wherein the phenyl ring in the substituted phenyl is substituted by one or more substituents selected from the group consisting of halogen, -NO2, -CN, phenyl, and C1-C4 alkyl; The nitrogen-containing heterobicyclic base is selected from the group consisting of: In formula (III), Y is -CH2-, -NH- or -N(CH3)-; n is 1 or 2; The phosphazene base compound has a structure shown in formula (IV): In formula (IV), R is halogen, C1-C4 alkyl or C1-C4 alkoxy.

3. The regeneration method according to claim 1 or 2, which satisfies one or more of the following characteristics: The number average molecular weight of the degradable polymer material is 10 kDa to 250 kDa; The mass ratio of water to the degradable polymer material in the system is (0.01-10):1; The mass ratio of the organic non-metallic catalyst to the degradable polymer material is (0.001-0.1):1; The average degree of polymerization of the degradation product is ≤20.

4. The regeneration method according to any one of claims 1 to 3, which satisfies one or more of the following characteristics: The degradable polymer material is selected from one or more of polylactic acid, polyglycolic acid, polyε-caprolactone, polylactic acid-glycolic acid copolymer, polyglycolic acid-ε-caprolactone copolymer, polylactic acid-ε-caprolactone copolymer, polyδ-valerolactone, polybutyrolactone, polybutylene succinate, polybutylene adipate / terephthalate, polybutylene succinate / adipate, polyhydroxyalkanoate and polytrimethylene carbonate; The diphenyl phosphate catalyst is selected from one or more of diphenyl phosphate, bis(4-nitrophenyl) phosphate, bis(4-fluorophenyl) phosphate, bis(4-trifluoromethylphenyl) phosphate, bis(4-chlorophenyl) phosphate, bis(4-methoxyphenyl) phosphate and bis(4-methylphenyl) phosphate; The binaphthol phosphate catalyst is selected from one or more of binaphthol phosphate, R-binaphthol phosphate, R-3,3'-bis(triphenylsilyl)binaphthol phosphonate and R-3,3'-bis(2,4,6-triisopropylphenyl)binaphthol phosphonate; The organic base catalyst is selected from 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazidobicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 4-dimethylaminopyridine, tert-butylimino-tris(dimethylamino)phosphorane, 1-tert-butyl-2,2,4,4,4-penta(dimethylamino)-2Λ5,4Λ5-bis(phosphorus nitrogen-based compound) and cyclotriphosphazene base and 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylideneamino]-2Λ5,4Λ5-bis(phosphorus nitrogen-based compound) One or more.

5. The regeneration method according to claim 1, comprising the following steps: In the system where the organic non-metallic catalyst and the aqueous solvent exist, subjecting the first degradable polymer material to a first degradation treatment to obtain a first degradation product; The i-th degradation product and the i+1-th degradable polymer material are mixed, and the i+1-th degradation treatment is performed to obtain the i+1-th degradation product, wherein i is an integer ≥1, and the i+1-th degradable polymer material includes at least the second degradable polymer material; the degradation treatment is terminated when i+1=n to obtain the n-th degradation product, wherein n is an integer ≥2, and the average degree of polymerization of the n-th degradation product is ≤20.

6. The regeneration method according to any one of claims 1 to 5, which satisfies one or more of the following characteristics: The temperature of any degradation treatment is independently 125°C to 200°C; The time of any degradation treatment is independently 0.1h to 5h, and can be optionally 0.25h to 5h; The pressure of any degradation treatment is independently 1 atm-100 atm, and can be optionally 100±5 kPa.

7. The regeneration method according to any one of claims 1 to 5 and 6, further comprising the following steps: The degradation product is washed with an organic solvent; wherein the organic solvent is selected from one or more of chloroform, petroleum ether, carbon disulfide, ether, dichloromethane, benzene, toluene and ethyl acetate.

8. A low molecular weight composition, wherein The low molecular weight composition is a degradation product of a degradable polymer material, and the low molecular weight composition is prepared according to the regeneration method according to any one of claims 1 to 7, wherein the average polymerization degree of the low molecular weight composition is ≤20.

9. A method for recycling a degradable polymer material, comprising the following steps: A polymerization reaction is carried out using a low molecular weight composition as an initial raw material; wherein the low molecular weight composition is a degradation product prepared by the regeneration treatment method described in claims 1 to 7 or the low molecular weight composition described in claim 8.

10. Application of organic non-metallic catalysts in the degradation of degradable polymer materials; in, The organic non-metallic catalyst and the degradable polymer material are as defined in any one of claims 1 to 4.

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