Degradable polyester compound as well as preparation method, degradation method and application thereof

Abstract

The invention provides a poly (delta-L dimer) as well as a preparation method, a degradation method and application thereof, and the poly (delta-L dimer) comprises a repetitive unit as shown in the following formula I: # imgabs0 # n and m are integers greater than 1. According to the technical scheme, poly (delta-L dimer) is obtained from delta-L through ring opening polymerization for the first time, polyester can be degraded, and the catalyst adopted in the method is good in catalytic activity and can inhibit the rate of Michael addition side reaction of delta-L to a certain extent.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer synthesis, and in particular to a degradable polyester compound and a preparation method, a degradation method and use thereof. Background Art

[0002] Global warming caused by greenhouse gases has already caused significant damage to the Earth's climate. Over 70% of these greenhouse gases are composed of CO2. Therefore, the recovery, enrichment, and utilization of CO2 have become particularly urgent. Furthermore, the vast majority of plastic products produced annually are single-use plastics, which are non-biodegradable and contribute significantly to environmental pollution.

[0003] If we can combine CO2 utilization with polymer synthesis, it will not only mitigate global warming, but polyesters using CO2 as a monomeric reaction raw material also have a high probability of becoming biodegradable and recyclable plastics. However, the vast majority of polymers obtained through currently known CO2-based polymer development pathways are either non-degradable or require very harsh degradation conditions. Therefore, if we want to completely solve the problem of plastic pollution, it is imperative to introduce biodegradability into the entire life cycle of CO2-based polymers.

[0004] Existing research has primarily employed two strategies for introducing CO2 into polymers. One involves direct CO2 polymerization as a monomer. However, CO2 is thermodynamically very stable, requiring the use of high-energy secondary monomers such as epoxides, aziridines, and hindered Lewis acids and bases. Furthermore, the reaction conditions are often harsh and the monomers expensive. Another strategy involves first generating monomers from CO2 and other substances, and then polymerizing these monomers to produce CO2-based polymers.

[0005] The telomerization reaction of CO2 with 1,3-butadiene to produce the unsaturated six-membered lactone δ-L (3-ethylidene-6-vinyl-tetrahydro-2H-pyran-2-one) containing lactone and olefin functional groups has attracted widespread attention. Both raw materials are inexpensive and readily available, and the lactone has a high potential for ring-opening to produce polyesters. However, current research on the polymerization of δ-L has not yet achieved ring-opening polymerization itself or the synthesis of biodegradable polyesters. The main reason is that the conjugated olefin structure contained in δ-L makes it a very active Michael addition receptor, which makes it difficult to achieve ring-opening polymerization under the conditions of traditional ring-opening polymerization catalysts.

[0006] Therefore, it is urgent to find a new catalyst that can inhibit the Michael addition side reaction of δ-L to realize the synthesis of degradable polyester using δ-L as the reaction raw material. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a polyester (hereinafter referred to as poly(δ-L dimer)) and its preparation method, degradation method and use, which are used to solve the related work of the prior art that has not yet achieved the ring-opening polymerization of δ-L itself or the synthesis of degradable polyesters.

[0008] To achieve the above-mentioned purpose and other related purposes, the present invention is achieved through the following technical solutions.

[0009] The first aspect of the present invention provides a poly(δ-L dimer) comprising a repeating unit as shown in the following formula I:

[0010]

[0011] n and m are integers greater than 1.

[0012] Preferably, the main chain structure of the poly (δ-L dimer) includes one or more of a linear structure and a star structure.

[0013] Preferably, the number average molecular weight of the poly(δ-L dimer) is 608-30,000 g / mol, such as 608-1,000 g / mol, 1,000-2,000 g / mol, 2,000-6,000 g / mol, 2,583-5,502 g / mol, 6,000-10,000 g / mol, 6,000-10,000 g / mol, 10,000-15,000 g / mol, 15,000-20,000 g / mol, or 20,000-30,000 g / mol.

[0014] Preferably, the molecular weight distribution of the poly (δ-L dimer) is 1.00-4.00, such as 1.07-2.23, 1.00-2.00, 2.00-3.00, or 3.00-4.00.

[0015] Preferably, the monomer of the poly(δ-L dimer) is δ-L, and the structural formula of the δ-L is shown in Formula II:

[0016]

[0017] A second aspect of the present invention provides a method for preparing the poly(δ-L dimer) as described above, comprising the steps of: reacting the δ-L shown in Formula II under a first catalyst condition to obtain the poly(δ-L dimer); the synthetic route of the reaction is as follows:

[0018] The first catalyst is selected from one or more of organic bases, alcohol salts, urea and its derivatives, and thiourea and its derivatives; n and m are integers greater than 1.

[0019] Preferably, the synthetic route of the reaction is as follows:

[0020]

[0021] Preferably, the organic base is selected from one or more of phosphazenes, compounds containing a guanidino group, and compounds containing an amidino group.

[0022] Preferably, the urea and its derivatives are selected from one or more of the structural formulas shown in Formula IV and Formula V.

[0023] Preferably, the thiourea and its derivatives are one or more of those shown in formula VI.

[0024]

[0025] Wherein, R1, R2, R3, R4, R5, and R6 are independently selected from one or more of C1-C30 alkyl, alkyl derivatives, aromatic groups, aromatic derivatives, hydrogen, alkenyl, alkenyl derivatives, alkynyl, and alkynyl derivatives.

[0026] Preferably, the alkoxide is selected from one or more of potassium tert-butoxide, sodium tert-butoxide, potassium methoxide, sodium methoxide, potassium ethoxide and sodium ethoxide.

[0027] Preferably, the molar ratio of the δ-L to the first catalyst is 50-100:0.1-10. For example, it may be 80-100:0.1-2.5, 80-100:1-2.5, 80-100:2.5-5, 90-100:0.1-2.5, 90-100:2.5-5.

[0028] More preferably, the first catalyst may be a mixture of an organic base, urea and its derivatives, and thiourea and its derivatives, or may be a mixture of an alkoxide, urea and its derivatives, and thiourea and its derivatives.

[0029] Preferably, an initiator is also used when the reaction occurs.

[0030] More preferably, when the first catalyst is selected from alkoxides, urea and its derivatives, and thiourea and its derivatives, the above reaction can occur without using an initiator.

[0031] More preferably, when the first catalyst is selected from organic bases, urea and its derivatives, and thiourea and its derivatives, an initiator is also used.

[0032] Preferably, the reaction also comprises a first reaction medium.

[0033] Preferably, the reaction temperature is -40°C to 0°C, such as -40°C to -25°C, -25°C to 0°C, or -30°C to -25°C.

[0034] Preferably, the reaction time is 60 to 80 hours, such as 60 to 72 hours, or 72 to 80 hours.

[0035] Preferably, after the reaction is completed, there is a post-processing step, which includes quenching the reaction, purification and drying.

[0036] Preferably, the initiator is selected from R(OH) m , wherein the initiator is selected from one or more of C1-C30 alkyl alcohols, C1-C30 alkyl alcohol derivatives, C1-C30 alkenyl alcohols, C1-C30 alkenyl alcohol derivatives, alkynyl alcohols, alkynyl alcohol derivatives, monocyclic aromatic alcohols, monocyclic aromatic alcohol derivatives, polycyclic aromatic alcohols, polycyclic aromatic alcohol derivatives, polyheterocyclic aromatic alcohols, polyheterocyclic aromatic alcohol derivatives, polyvinyl alcohol with a molecular weight of 10,000 g / mol or less, and polyethylene glycol with a molecular weight of 10,000 g / mol or less.

[0037] Preferably, the organic base is selected from t Bu-P4, t Bu-P2, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), t One or more of Bu-P1, IMes, diethylamine, dimethylamine, triethylamine, N-methylmorpholine, n-octylamine, tri-n-butylamine, laurylamine, stearylamine, tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH), sodium or potassium alcoholates of C1 to C5, triethanolamine, choline, N-methylmorpholine, pyridine, dimethylaminopyridine, N,N'-dihydroxyethylethylenediamine, β-hydroxyethylethylenediamine, N-(2-hydroxyethyl)ethylenediamine, N,N,N',N'-tetrahydroxyethylethylenediamine, N-hydroxyethylpropylenediamine, trimethylhydroxyethylpropylenediamine, and N,N'-di(2-hydroxyethyl)-1,3-propylenediamine.

[0038] Preferably, the urea and its derivatives and thiourea and its derivatives are selected from diphenylurea. Only when the first catalyst includes diphenylurea, the reaction may generate poly (delta-L dimer) product.

[0039] Preferably, when an initiator is used, the molar ratio of the δ-L, first catalyst, and initiator is 50:0.1-10:0.1-10. For example, it can be 50:1-5:0.1-1, 50:1-2.5:0.1-1, or 50:2.5-5:1-3. This feed ratio range is not set arbitrarily. If the content of the first catalyst is too high, the occurrence of the Michael addition side reaction cannot be effectively suppressed. If the content of the first catalyst is too low, the ring-opening polymerization reaction rate is extremely slow. Only when this feed ratio is achieved and the first catalyst contains diphenylurea can the poly (δ-L dimer) be obtained by reaction.

[0040] Preferably, the first reaction medium is one or more of tetrahydrofuran (THF), TBD, benzene, toluene, xylene, dichlorobenzene, mesitylene, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydropyrrole, tetrahydropyran, hexahydropyridine, ethyl acetate, ethyl ether, dimethyl ether, methyl ethyl ether, n-hexane, cyclohexane, cyclopentane, acetonitrile, dioxane, N,N-dimethylformamide and dimethyl sulfoxide.

[0041] Preferably, the quenching is performed using a saturated benzoic acid solution in tetrahydrofuran.

[0042] Preferably, the purification method includes one or both of an anti-solvent method and a centrifugation method.

[0043] More preferably, in the anti-solvent method, the anti-solvent is selected from one or more of MeOH, EtOH and n-hexane.

[0044] More preferably, the centrifugal rotation speed is 8000-130000 rpm.

[0045] Preferably, the initiator includes one or more of benzyl alcohol (BnOH), 1,4-butanediol, benzhydrol, PEG, terephthalic acid, and 1,3-propylene glycol.

[0046] More preferably, when the first catalyst is a mixture of an organic base, urea and its derivatives, and thiourea and its derivatives, the amount of the organic base is ≤ the amount of the urea and its derivatives, and thiourea and its derivatives.

[0047] More preferably, when the first catalyst is a mixture of alkoxide, urea and its derivatives, and thiourea and its derivatives, the amount of the alkoxide is less than or equal to the amount of the urea and its derivatives, and thiourea and its derivatives.

[0048] A third aspect of the present invention provides a method for degrading poly(δ-L dimer), which includes a catalytic method and / or a thermal decomposition method; the catalytic method includes: using a second catalyst to degrade poly(δ-L dimer); the thermal decomposition method includes: heating the poly(δ-L dimer) to crack it to obtain its oligomers or derivatives.

[0049] Preferably, the second catalyst comprises one or more of La[N(SiMe3)2]3, sodium hydroxide, potassium hydroxide, lithium hydroxide and calcium hydroxide.

[0050] Preferably, the molar ratio of the poly (δ-L dimer) to the second catalyst is 100-10:3-0.1, such as 50-10:3-1, or 50-10:2.

[0051] Preferably, the heating temperature is 60°C to 150°C, such as 60°C to 80°C, 80°C to 100°C, 80°C to 120°C, or 80°C to 150°C.

[0052] Preferably, the heating time is 12 to 36 hours.

[0053] Preferably, the degradation process can be carried out in the presence of a solvent or in the absence of a solvent.

[0054] When the degradation is carried out in a solvent, the solvent may be selected from one or more of water, toluene, xylene, dichlorobenzene, mesitylene, dioxane, N,N-dimethylformamide and dimethyl sulfoxide.

[0055] Preferably, the degradation is carried out in an inert gas atmosphere. More preferably, the inert gas comprises nitrogen.

[0056] A fourth aspect of the present invention provides a use of the poly (δ-L dimer) as described above as a reaction raw material in the preparation of polyurethane, wherein the reaction raw material further comprises isocyanate.

[0057] More preferably, the isocyanate is selected from phenyl isocyanate.

[0058] A fifth aspect of the present invention provides a polyurethane, which is obtained by catalyzing the reaction of the poly (δ-L dimer) and isocyanate as described above with a third catalyst.

[0059] Preferably, the third catalyst is selected from organotin compounds.

[0060] Preferably, the organotin compound includes one or more of dibutyltin diacetate, dibutyltin dilaurate and stannous octoate.

[0061] In the prior art, in the reaction system of δ-L ring-opening polymerization, the presence of conjugated olefins in δ-L causes the Michael addition reaction of δ-L to occur immediately upon monomer addition. However, the applicants of the present application discovered that when equivalent amounts of an organic base are mixed with urea and its derivatives and thiourea and its derivatives as catalysts, the hydrogen atoms on the structural nitrogen atoms of the urea and its derivatives and thiourea and its derivatives prematurely stabilize the basic groups of the organic bases, forming stable intermediates, thereby suppressing the rate of the Michael addition side reaction to a certain extent.

[0062] The beneficial effects of the present invention are:

[0063] 1) The technical solution of the present invention realizes for the first time the production of degradable poly (δ-L dimer) by ring-opening polymerization of δ-L. The poly (δ-L dimer) has good thermodynamic properties, a suitable glass transition temperature, and a high decomposition temperature, and has potential application value in the subsequent preparation of various polymer products.

[0064] 2) The polymerization reaction of the present invention uses δ-L generated by the polymerization of CO2 and 1,3-butadiene as a monomer, which can not only effectively utilize carbon dioxide to reduce the greenhouse effect, but also has low cost and easy access to raw materials.

[0065] 3) The poly (δ-L dimer) prepared by this technical solution is not only degradable, thereby reducing environmental pollution, but also the side chain of the polyester retains olefin groups, which makes it have strong post-modification modification ability and has potential application value in the subsequent preparation of various polymer products.

[0066] 4) The first catalyst used in the preparation method of the present invention has good catalytic activity and can inhibit the rate of the Michael addition side reaction of δ-L to a certain extent. The preparation method is simple and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 Shown is the hydrogen nuclear magnetic resonance spectrum of poly (δ-L dimer) prepared in Example 1 of the present invention.

[0068] Figure 2 Shown is a comparison chart of gel permeation chromatography (GPC) before and after degradation of poly (δ-L dimer) in Example 4 of the present invention.

[0069] Figure 3 Shown is the DSC chart of poly (δ-L dimer) prepared in Example 1 of the present invention.

[0070] Figure 4 Shown is the TGA chart of poly(δ-L dimer) prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0071] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0072] Before further describing the specific embodiments of the present invention, it should be understood that the scope of the present invention is not limited to the specific embodiments described below. It should also be understood that the terminology used in the examples is intended to describe specific embodiments and is not intended to limit the scope of the present invention. The experimental procedures in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0073] When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the understanding of the prior art by those skilled in the art and the description of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention may also be used to implement the present invention.

[0074] Example 1

[0075] This embodiment provides a specific poly (δ-L dimer) and a preparation method thereof.

[0076] The catalyst for anionic ring-opening polymerization in this embodiment is: t Bu-P4 and diphenylurea (U2) were used as catalysts for anionic ring-opening polymerization; the initiator was BnOH.

[0077] In [δ-L], [ t The reaction was stirred in 0.2 mL of tetrahydrofuran (THF) solution at -25 ° C. for 72 h (the [δ-L] was 39.4 mol / L), and quenched with 5 mL of saturated benzoic acid solution in tetrahydrofuran to obtain 5.2 mL of the first solution.

[0078] After quenching, 300 mL of MeOH was added dropwise to the first solution, followed by centrifugation at 10,000 rpm for 10 minutes. The resulting precipitate was retained and the same volume of MeOH was added and centrifuged three times. The resulting solid was then dried in a vacuum oven at 50°C for 12 hours to obtain poly(δ-L dimer) with a molecular weight of 4513 g / mol and a molecular weight distribution of 2.23. The conversion rate of δ-L was 100%.

[0079] The H NMR spectrum of the poly(δ-L dimer) prepared in this example is shown in Figure 1 The specific steps are as follows: using a BRUKER AVANCE III HD500 nuclear magnetic resonance instrument to analyze the sample, setting the receiving gain (rg) = 1, the number of scans (ns) = 8, and then collecting and analyzing the sample data to obtain a hydrogen nuclear magnetic resonance spectrum.

[0080] Depend on Figure 1 As can be seen, the ratio of the NMR integral of the conjugated olefin portion (near δ6.95 ppm) to the terminal olefin (near δ5.85 ppm) is 1.00:2.16, indicating that the polymer is composed primarily of the δ-L dimer as the repeating unit. Furthermore, the signal at the chemical shift near δ4.75 ppm, based on our previous work, represents the hydrogen signal (p, e') ortho to the ester oxygen in the unopened six-membered ring in the polymer, with an integral of 0.91. Therefore, the ratio of the integral at δ5.85 ppm to the integral at δ4.75 ppm (2.16:0.91) represents the ratio of the total number of δ-L rings participating in the reaction to the number of ring-opened six-membered rings. The ring-opened fraction is 2.16-0.91=1.25, which is greater than half of the participating monomers. Therefore, ring-opening polymerization of the δ-L six-membered ring structure must have occurred, confirming the synthesis of poly(δ-L dimer) using this method.

[0081] Example 2

[0082] This embodiment provides a specific poly (δ-L dimer) and a preparation method thereof.

[0083] The catalyst for anionic ring-opening polymerization in this embodiment is potassium tert-butoxide ( t BuOK) and diphenylurea (U2) were used as catalysts for anionic ring-opening polymerization.

[0084] In [δ-L], [ t The reaction was stirred in 0.2 mL of tetrahydrofuran (THF) solution at -25 ° C. for 72 h (the [δ-L] was 39.4 mol / L), and quenched with 5 mL of saturated benzoic acid solution in tetrahydrofuran to obtain 5.2 mL of the first solution.

[0085] After quenching, 300 mL of MeOH was dropwise added to the first solution, and the mixture was centrifuged at 10,000 rpm for 10 minutes. The resulting precipitate was retained and the supernatant discarded. The same volume of MeOH was added and centrifuged three times. The resulting solid was then dried in a vacuum oven at 50°C for 12 hours to obtain poly(δ-L dimer), which had a molecular weight of 5502 g / mol and a molecular weight distribution of 1.07. The conversion rate of δ-L was 76%.

[0086] Example 3

[0087] This embodiment provides a specific poly (δ-L dimer) and a preparation method thereof.

[0088] The catalyst for anionic ring-opening polymerization in this embodiment is: t Bu-P4 and diphenylurea (U2) were used as catalysts for anionic ring-opening polymerization; the initiator was 1,4-butanediol (1,4-BDO).

[0089] In [δ-L], [ t The reaction was stirred in 0.2 mL of tetrahydrofuran (THF) solution at -25 ° C. for 72 h (the [δ-L] was 39.4 mol / L), and quenched with 5 mL of saturated benzoic acid solution in tetrahydrofuran to obtain 5.2 mL of the first solution.

[0090] After quenching, 300 mL of MeOH was dropwise added to the first solution, and the mixture was centrifuged at 10,000 rpm for 10 minutes. The resulting precipitate was retained and the supernatant discarded. The same volume of MeOH was added and centrifuged three times. The resulting solid was then dried in a vacuum oven at 50°C for 12 hours to obtain poly(δ-L dimer). Its molecular weight was 2583 g / mol, and its molecular weight distribution was 1.32. The conversion rate of δ-L was 80%.

[0091] Example 4

[0092] This example provides a specific method for degrading poly(δ-L dimer).

[0093] Under a nitrogen atmosphere, 2 mL of 1 M NaOH solution and 11.1 mmol of the poly(δ-L dimer) sample prepared in Example 1 were added to a Schlenk tube, followed by heating and stirring in an 80 ° C heating block for 24 h. After that, the solvent in the system was removed by rotary evaporation to complete the degradation of poly(δ-L dimer).

[0094] Take out 10mg of the degraded product and analyze the polymer degradation by GPC. The results are as follows Figure 2 As shown. Figure 2 As can be seen, the red GPC signal for poly(δ-L dimer) has a significantly shorter retention time than the black signal, indicating a higher molecular weight. Furthermore, the retention time of the black peak is essentially the same as that of the solvent peak, indicating that no polymer remains, indicating that the poly(δ-L dimer) prepared in Example 1 has been degraded.

[0095] The specific process of GPC analysis is as follows: a Malvern GPC TDA305 was used, the chromatographic column was a D6000M universal mixed organic phase column, equipped with an ultraviolet detector (UV), a differential refractive index detector (RI), and a light scattering detector (RALS and LALS), and the flow rate was set to 1 ml min -1 The column temperature was set at 40°C, and the analysis was performed to obtain a GPC analysis chart.

[0096] Application Example 1

[0097] 241.7 mg of poly (δ-L dimer) and 23.39 mg of 4,4'-methylenebis(phenyl isocyanate) prepared in Example 3 were taken, 0.2 mL of THF solvent was added, and after complete dissolution, 1.32 mg of dibutyltin diacetate was added as a catalyst, and the mixture was reacted at -25 ° C for 24 hours. After the reaction, 5 mL of tetrahydrofuran was added to dilute the reaction system to obtain a mixture solution, and the mixture solution was added dropwise to 300 mL of methanol at 0 ° C, centrifuged at 10000 rpm for 10 minutes, the supernatant was discarded and the solid was retained, and the reaction was repeated 3 times. Finally, the bottom solid was retained and vacuum dried at 60 ° C for 12 hours to obtain a polyurethane with δ-L dimer as a repeating unit.

[0098] The applicant conducted a thermal performance analysis on the poly (δ-L dimer) prepared in Example 1. The specific method is as follows:

[0099] 1) Differential Scanning Calorimetry (DSC)

[0100] The poly (δ-L dimer) prepared in Example 1 was tested using a Per Elmer DSC 8500 differential scanning calorimeter. The entire test was performed at 10°C min -1 The temperature change rate is completed by first heating from 30℃ to 150℃ to eliminate the thermal vector, then cooling to -80℃, then heating to 150℃, and then cooling to -80℃. The endothermic and exothermic curves of the last two sections (heating to 150℃ and then cooling to -80℃) are taken as the demonstration. The specific results are shown in Figure 3 .

[0101] T g is the glass transition temperature, which represents the temperature at which the first chain segment in the polymer moves.

[0102] Depend on Figure 3 It can be seen that the T of poly (δ-L dimer) prepared in Example 1 g The temperature is 88.62℃, which meets the T g Generally, the requirement is above 70° C. Therefore, the poly (δ-L dimer) prepared in Example 1 has a suitable glass transition temperature and can meet the requirements of being plastic upon heating and solid at room temperature in subsequent applications.

[0103] 2) Thermogravimetric analysis (TGA)

[0104] Using a Perk Elmer TGA 8000 thermogravimetric analyzer, the temperature was raised from 30°C to 600°C at a rate of 10°C min-1 under a nitrogen atmosphere. The poly (δ-L dimer) prepared in Example 1 was used as a sample to observe its weight change. Specific results are shown in Figure 4 .

[0105] Td,5% and Tmax are the temperature at which the sample weight decreases by 5% and the temperature at which the decomposition rate is maximum, respectively.

[0106] Depend on Figure 4 It can be seen that the Td,5% of poly(δ-L dimer) is 314.68° C. and Tmax is 475.25° C. This indicates that the poly(δ-L dimer) prepared in Example 1 has stable thermodynamic properties and a high decomposition temperature.

[0107] In summary, the technical solution provided by the present invention achieves, for the first time, the production of poly (δ-L dimer) from δ-L through ring-opening polymerization. This polyester is not only degradable but also exhibits excellent thermodynamic properties, a suitable glass transition temperature, and a high decomposition temperature, showing potential application in the subsequent preparation of a variety of polymer products. The raw material δ-L utilized in the technical solution of the present invention is synthesized from CO2 and 1,3-butadiene, which are inexpensive and readily available. Furthermore, the first catalyst employed in the method of the present invention exhibits excellent catalytic activity, capable of suppressing the rate of the Michael addition side reaction of δ-L to a certain extent.

[0108] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A polyester, characterized in that Contains the repeating unit shown in the following formula I: n and m are integers greater than 1.

2. The polyester according to claim 1, characterized in that The main chain structure of the polyester includes one or both of a linear structure and a star structure; and / or, the number average molecular weight of the polyester is: 608 to 30,000 g / mol; And / or, the molecular weight distribution of the polyester is: 1.00 to 4.00; And / or, the monomer of the polyester is δ-L, and the structural formula of δ-L is shown in Formula II:

3. A method for preparing the polyester according to claim 1 or 2, characterized in that: The method comprises the following steps: δ-L as shown in formula II reacts under a first catalyst condition to obtain polyester; the synthesis route of the reaction is as follows: The first catalyst is selected from one or more of organic bases, alkoxides, urea and its derivatives, and thiourea and its derivatives; n and m are integers greater than 1.

4. The preparation method according to claim 3, characterized in that The organic base is selected from one or more of phosphazenes, compounds containing guanidino groups, and compounds containing amidino groups; And / or, the urea and its derivatives are selected from one or more of the structural formulas shown in Formula IV and Formula V; And / or, the thiourea and its derivatives are selected from one or more of the structural formulas shown in Formula VI; wherein R1, R2, R3, R4, R5, and R6 are independently selected from one or more of C1-C30 alkyl, alkyl derivatives, aromatic groups, aromatic derivatives, hydrogen, alkenyl, alkenyl derivatives, alkynyl, and alkynyl derivatives; and / or, the alkoxide is selected from one or more of potassium tert-butoxide, sodium tert-butoxide, potassium methoxide, sodium methoxide, potassium ethoxide and sodium ethoxide; and / or, the molar ratio of the δ-L to the first catalyst is 50-100:0.1-10; And / or, when the reaction occurs, an initiator is also used; and / or, the reaction further comprises a first reaction medium; And / or, the reaction temperature is -40°C to 0°C; And / or, after the reaction is completed, there is a post-processing step, which includes quenching the reaction, purification and drying.

5. The preparation method according to claim 4, characterized in that The initiator is selected from R(OH) m , wherein the initiator is selected from one or more of C1-C30 alkyl alcohols, C1-C30 alkyl alcohol derivatives, C1-C30 alkenyl alcohols, C1-C30 alkenyl alcohol derivatives, alkynyl alcohols, alkynyl alcohol derivatives, monocyclic aromatic alcohols, monocyclic aromatic alcohol derivatives, polycyclic aromatic alcohols, polycyclic aromatic alcohol derivatives, polyheterocyclic aromatic alcohols, polyheterocyclic aromatic alcohol derivatives, polyvinyl alcohol with a molecular weight of 10,000 g / mol or less, and polyethylene glycol with a molecular weight of 10,000 g / mol or less; And / or, the organic base is selected from t Bu-P4, t Bu-P2, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene, t One or more of Bu-P1, IMes, diethylamine, dimethylamine, triethylamine, N-methylmorpholine, n-octylamine, tri-n-butylamine, laurylamine, stearylamine, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, sodium or potassium alcoholates of C1 to C5, triethanolamine, choline, N-methylmorpholine, pyridine, dimethylaminopyridine, N,N'-dihydroxyethylethylenediamine, β-hydroxyethylethylenediamine, N-(2-hydroxyethyl)ethylenediamine, N,N,N',N'-tetrahydroxyethylethylenediamine, N-hydroxyethylpropylenediamine, trimethylhydroxyethylpropylenediamine, and N,N'-di(2-hydroxyethyl)-1,3-propylenediamine; and / or, urea and its derivatives are selected from diphenylurea; and / or, when an initiator is used, the molar ratio of the δ-L, the first catalyst and the initiator is 50:0.1-10:0.1-10; and / or, the first reaction medium is one or more of tetrahydrofuran, TBD, benzene, toluene, xylene, dichlorobenzene, mesitylene, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydropyrrole, tetrahydropyran, hexahydropyridine, ethyl acetate, ethyl ether, dimethyl ether, methyl ethyl ether, n-hexane, cyclohexane, cyclopentane, acetonitrile, dioxane, N,N-dimethylformamide and dimethyl sulfoxide; and / or, using a saturated benzoic acid tetrahydrofuran solution for the quenching; And / or, the purification method includes one or both of an anti-solvent method and a centrifugation method.

6. The preparation method according to claim 5, characterized in that The initiator includes one or more of benzyl alcohol, 1,4-butanediol, benzhydrol, PEG, terephthalic acid, and 1,3-propylene glycol; and / or, when the first catalyst is a mixture of an organic base, urea and its derivatives, and thiourea and its derivatives, the amount of the organic base is less than or equal to the amount of the urea and its derivatives, and thiourea and its derivatives; And / or, when the first catalyst is a mixture of alkoxide, urea and its derivatives, and thiourea and its derivatives, the amount of the alkoxide is less than or equal to the amount of the urea and its derivatives, and thiourea and its derivatives.

7. A method for degrading polyester according to claim 1 or 2, characterized in that: The method includes a catalytic method and / or a thermal decomposition method; the catalytic method includes: using a second catalyst to degrade the polyester; the thermal decomposition method includes: heating the polyester to crack it to obtain its oligomer or derivatives.

8. The degradation method according to claim 7, characterized in that: The second catalyst comprises one or more of La[N(SiMe3)2]3, sodium hydroxide, potassium hydroxide, lithium hydroxide and calcium hydroxide; And / or, the molar ratio of the polyester to the second catalyst is 100-10:3-0.

1. And / or, the heating temperature is 60°C to 150°C.

9. Use of the polyester according to claim 1 or 2 as a reaction raw material in the preparation of polyurethane, characterized in that: The reaction raw materials also include isocyanate.

10. A polyurethane, characterized in that The polyester and isocyanate as claimed in claim 1 or 2 are used to obtain the polyester through a catalytic reaction using a third catalyst.

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