Monomeric recyclable cyclic carbon dioxide-based polymers, methods of making and uses thereof

Abstract

The application belongs to the technical field of polymer synthesis, and relates to a cyclic polymer and a synthesis method thereof, wherein the method is to take a heterocyclic lactone of formula 1 as raw material, and to perform ring-opening polymerization under the catalysis of an organic base to obtain the cyclic polymer of formula 2. The method realizes the preparation of the cyclic polymer with ultrahigh molecular weight and medium molecular weight distribution for the first time. The raw material used in the preparation method has a wide source, the catalyst used has good catalytic activity, the preparation is simple, and the cost is low. The method can effectively alleviate the harm caused by the greenhouse effect. The application also discloses the application of the cyclic polymer. The prepared polymer film is colorless, transparent, and has good flexibility and viscoelasticity. The application also discloses a recycling method of the cyclic polymer. The recycling method has a wide spectrum of substrates, can effectively recycle the heterocyclic lactone monomer in the cyclic polymer, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis technology, and relates to a monomerically recyclable cyclic carbon dioxide-based polymer, its preparation method and uses. Specifically, it relates to a CO2-based chemical recyclable polymer and its synthesis method, particularly to the synthesis of a CO2-based chemical recyclable polymer / polyester material by using a saturated lactone synthesized from inexpensive and readily available C1 sources CO2, H2 and the bulk chemical raw material 1,3-butadiene through anionic ring-opening polymerization. Background Technology

[0002] Synthetic polymers, as common materials, have permeated every aspect of human life, from clothing and food to housing and transportation. It is predicted that from 1950 to 2050, global polymer production will accumulate to 34 billion tons, and the vast majority of these polymers are difficult to degrade due to their stable carbon-carbon backbone. The extensive use of non-degradable polymers has resulted in an irrational linear utilization pattern of "raw materials-monomers-polymers-materials-waste," which directly leads to the severe plastic waste pollution and countless losses of material value we see today.

[0003] CO2 is an inexpensive, readily available, and renewable C1 source, making it well-suited for synthesizing various polymers, including polycarbonates, polyurethanes, polyureas, and polyesters. The synthesis of novel polymers, particularly ethylene and 1,3-butadiene, using CO2 and readily available, inexpensive chemicals has been a significant challenge since the 1970s. A Pd-catalyzed coupling reaction between Inoue, Behr, Beller CO2, and 1,3-butadiene can generate a six-membered ring lactone intermediate (3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one) containing two carbon-carbon double bonds. Based on this, Nozaki reported the radical polymerization of δ-L in 2014, yielding polyolefins with three different topologies containing ester functional groups in the side chains. Following this, Lin Bolin reported that this monomer can undergo direct radical polymerization under air-initiated, solvent-free, and additive-free conditions, and discovered a fourth structure (δ-structure) during the topological analysis. However, despite previous advances, it remains crucial to incorporate biodegradable functional groups into these polymers to address the significant issues of white pollution and material value loss.

[0004] Chemical recycling is a promising strategy for reducing the environmental and economic impact of polymer materials. It can achieve a closed-loop material economy through a "synthesis, utilization, and recycling" strategy, recovering used polymer materials back to monomers, which can then be polymerized again to obtain polymers with identical properties. This circular economy model is a very promising means of solving white pollution (plastic pollution). Simultaneously, synthesizing chemically recyclable polymers using inexpensive and readily available bulk chemicals, such as CO2 and olefins, can reduce material costs and drive large-scale industrial production. Developing efficient carbon dioxide conversion and utilization is of great significance for industrial production and sustainable development. However, existing CO2-based polymers are mainly limited to polycarbonates copolymerized from CO2 and propylene oxide monomers, failing to simultaneously meet the requirements of cost, material performance, and biodegradability. Therefore, to establish the advantages of CO2-based polymers in terms of cost, material performance, and a closed-loop circular economy, it is urgent to design and synthesize a novel, low-cost CO2-based polymer with industrial potential. Summary of the Invention

[0005] To overcome the aforementioned deficiencies of the prior art, this invention provides a synthetic route for a CO2-based chemically recyclable cyclic polymer (or polyester polymer material, cyclic lactone). Using heterocyclic lactones as raw materials, this cyclic polymer is synthesized through anionic ring-opening polymerization, and it can degrade back to the lactone monomer HL under specific conditions. Figures 1-2 ).

[0006] One aspect of the present invention is to provide a cyclic polymer comprising repeating units as shown in Formula 4:

[0007]

[0008] R1 and R2 are each independently selected from any one of hydrogen, halogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, monocyclic aromatic, substituted monocyclic aromatic, polycyclic aromatic, substituted polycyclic aromatic, polyheterocyclic aromatic, and substituted polyheterocyclic aromatic; the monocyclic aromatic is selected from phenyl, azirroaromatic, thioaromatic, and oxaaromatic; the polycyclic aromatic and polyheterocyclic aromatics refer to groups containing two or more monocyclic aromatics; R1 and R2 may be the same or different, and must coexist.

[0009] X is selected from heteroatoms;

[0010] n is a positive integer greater than or equal to 1.

[0011] Preferably, the cyclic polymer structure is as shown in Formula 2:

[0012]

[0013] Another aspect of the present invention is to provide the application of the cyclic polymers described above in the preparation of polymer films, pressure-sensitive adhesives, and thermoplastic elastomers.

[0014] Another aspect of the present invention provides a method for synthesizing a cyclic polymer, the method comprising: synthesizing a cyclic polymer of formula 2 from a heterocyclic lactone represented by formula 1 under the catalysis of an organic base; the reaction process is shown in reaction formula (I):

[0015]

[0016] Wherein, R1 and R2 are independently selected from any one of hydrogen, halogen, alkyl, substituted alkyl (linear alkyl, branched alkyl, cycloalkyl), alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, monocyclic aromatic, substituted monocyclic aromatic, polycyclic aromatic, substituted polycyclic aromatic, polyheterocyclic aromatic, and substituted polyheterocyclic aromatic; the monocyclic aromatic includes phenyl, azirroaromatic, thioaromatic, and oxaaromatic; the polycyclic aromatic and polyheterocyclic aromatic refer to groups containing two or more monocyclic aromatic groups; R1 and R2 may be the same or different, and must coexist;

[0017] X is selected from heteroatoms;

[0018] n is a positive integer greater than or equal to 1;

[0019] The organic base includes phosphazenes, compounds containing guanidine groups, and compounds containing amidine groups.

[0020] Another aspect of the present invention is to provide a cyclic polymer, which is synthesized by the method described above.

[0021] Another aspect of the present invention provides a polymer product prepared from the cyclic polymer described above. In one specific embodiment, the cyclic polymer is a polymer film. In another specific embodiment, the cyclic polymer is an adhesive tape.

[0022] Another aspect of the present invention provides the use of an organic base in the catalytic synthesis of a heterocyclic lactone of Formula 1 into a cyclic polymer of Formula 2, wherein the organic base includes phosphazenes, compounds containing guanidine groups, and compounds containing amidine groups; wherein the heterocyclic lactone of Formula 1 and the cyclic polymer of Formula 2 have the following structures:

[0023]

[0024] Wherein, R1 and R2 are independently selected from any one of hydrogen, halogen, alkyl, substituted alkyl (linear alkyl, branched alkyl, cycloalkyl), alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, monocyclic aromatic, substituted monocyclic aromatic, polycyclic aromatic, substituted polycyclic aromatic, polyheterocyclic aromatic, and substituted polyheterocyclic aromatic; the monocyclic aromatic includes phenyl, azirroaromatic, thioaromatic, and oxaaromatic; the polycyclic aromatic and polyheterocyclic aromatic refer to groups containing two or more monocyclic aromatic groups; R1 and R2 may be the same or different, and must coexist;

[0025] X is selected from heteroatoms;

[0026] n is a positive integer greater than or equal to 1;

[0027] The organic base includes phosphazenes, compounds containing guanidine groups, and compounds containing amidine groups.

[0028] Another aspect of the present invention is to provide a method for recovering heterocyclic monomers from catalytic 2-cyclic polymers, the method comprising an inorganic salt pyrolysis catalysis method and a La[N(SiMe3)2]3 mild catalysis method;

[0029]

[0030] Wherein, R1 and R2 are independently selected from any one of hydrogen, halogen, alkyl, substituted alkyl (linear alkyl, branched alkyl, cycloalkyl), alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, monocyclic aromatic, substituted monocyclic aromatic, polycyclic aromatic, substituted polycyclic aromatic, polyheterocyclic aromatic, and substituted polyheterocyclic aromatic; the monocyclic aromatic includes phenyl, azirroaromatic, thioaromatic, and oxaaromatic; the polycyclic aromatic and polyheterocyclic aromatic refer to groups containing two or more monocyclic aromatic groups; R1 and R2 may be the same or different, and must coexist;

[0031] X is selected from heteroatoms;

[0032] n is a positive integer greater than or equal to 1;

[0033] The organic base includes phosphazenes, compounds containing guanidine groups, and compounds containing amidine groups.

[0034] The inorganic salt pyrolysis catalytic method includes: using inorganic salt catalytic degradation of the cyclic polymer as shown in Formula 2 to obtain the heterocyclic compound or its oligomer or corresponding derivative of Formula 1 as shown in Formula 1;

[0035] The La[N(SiMe3)2]3 mild catalytic method includes: catalytically cracking the cyclic polymers described above using La[N(SiMe3)2]3 under mild conditions to obtain the heterocyclic compound or its oligomer or the corresponding derivative of Formula 1.

[0036] Compared with the prior art, the beneficial effects of the present invention include:

[0037] The heterocyclic lactones used in the method of this invention are widely available and simple to prepare. When the heterocyclic lactone is HL, the HL can be prepared by CO2 and 1,4-butadiene, which can alleviate the harm caused by the greenhouse effect caused by CO2.

[0038] The catalyst used in the method of this invention has good catalytic activity, the preparation method is simple, and the cost is low.

[0039] The method of this invention can synthesize cyclic polymers with ultra-high molecular weight and medium molecular weight distribution. In some embodiments, the molecular weight of the cyclic polymer can reach 613.8 kg mol⁻¹, and the molecular weight distribution D is 1.45. The cyclic polymer can be used to prepare a variety of polymer products, such as polymer films and tapes; the prepared polymer films are colorless and transparent, and have good flexibility and viscoelasticity.

[0040] The method for recovering cyclic polymers provided by this invention has a broad substrate spectrum and can effectively recover monomers from various cyclic polymers, including but not limited to cyclic polymers prepared by the method described in this invention, and has broad application prospects. Attached Figure Description

[0041] Figure 1 This document outlines the chemical recycling route for preparing cyclic polymers from CO2 and butadiene.

[0042] Figure 2 This is a schematic diagram illustrating the mechanism of synthesizing cyclic polymers from HL ring-opening polymers.

[0043] Figure 3 Kinetic data for the HL ring-opening polymerization catalyzed by tBu-P4. a. Conversion rate versus time; b. ln([M]0 / [M]) versus reaction time; c. Number-average molecular weight and molecular weight distribution versus conversion; d. Overlay plot of GPC curves from different embodiments.

[0044] Figure 4 MALDI-TOF characterization data for the cyclic PolyHL product prepared in Example 18.

[0045] Figure 5The 1H NMR spectrum of the cyclic polyHL polymer is shown in Example 3.

[0046] Figure 6 The 13C NMR spectrum of the cyclic polyHL polymer (Example 3).

[0047] Figure 7 MALDI-TOF characterization of polyHL products when the system was not strictly dehydrated.

[0048] Figure 8 HL and at different ratios t Bu-P4 mixed experiment ( 31 (P NMR spectrum).

[0049] Figure 9 For HL and at different ratios t Bu-P4 mixed experiment ( 1 (H NMR spectrum, magnified locally).

[0050] Figure 10 HL and at different ratios t Bu-P4 mixed experiment ( 1 H NMR spectrum, overview).

[0051] Figure 11 The free energy calculation data for tBu-P4 for the deprotonation of BnOH, HL and water are provided.

[0052] Figure 12 TGA and DTG curves of cyclic polyHL products.

[0053] Figure 13 The DSC curves are for the cyclic polyHL products.

[0054] Figure 14 Performance determination of pressure-sensitive adhesive for ring-shaped polyHL samples. a. Schematic diagram of 180° peel test; b. SEM image of cross-section of ring-shaped polyHL film (Example 3); c. Results of 180° peel performance test of ring-shaped polyHL sample and three commercial tapes (data shown in Table 3); d. Sample display of colorless and light-transmitting polyHL film (Example 3).

[0055] Figure 15 The image shows the 1H NMR spectrum of the polyHL polymer prepared in Example 4.

[0056] Figure 16 The image shows the 1H NMR spectrum of the polyHL polymer prepared in Example 5.

[0057] Figure 17 The image shows the 1H NMR spectrum of the polyHL polymer prepared in Example 6.

[0058] Figure 18 The image shows the 1H NMR spectrum of the product after degradation in Example 24.

[0059] Figure 19 The image shows the 1H NMR spectrum of the product after degradation in Example 25.

[0060] Figure 20 The image shows the 1H NMR spectrum of the product after degradation in Example 26.

[0061] Figure 21 The image shows the 1H NMR spectrum of the product after degradation in Example 27.

[0062] Figure 22 The image shows the 1H NMR spectrum of the product after degradation in Example 28.

[0063] Figure 23 The image shows the 1H NMR spectrum of the product after degradation in Example 29.

[0064] Figure 24 The image shows the 1H NMR spectrum of the product after degradation in Example 30.

[0065] Figure 25 The image shows the 1H NMR spectrum of the product after degradation in Example 31.

[0066] Figure 26 The image shows the 1H NMR spectrum of the product after degradation in Example 32.

[0067] Figure 27 The image shows the 1H NMR spectrum of the product after degradation in Example 33.

[0068] Figure 28 The image shows the 1H NMR spectrum of the product after degradation in Example 34.

[0069] Figure 29 The image shows the 1H NMR spectrum of the product after degradation in Example 35.

[0070] Figure 30 The image shows the 1H NMR spectrum of the product after degradation in Example 36.

[0071] Figure 31 The image shows the 1H NMR spectrum of the product after degradation in Example 37.

[0072] Figure 32 The image shows the 1H NMR spectrum of the product after degradation in Example 38.

[0073] Figure 33 The image shows the 1H NMR spectrum of the product after degradation in Example 39.

[0074] Figure 34 The image shows the 1H NMR spectrum of the product after degradation in Example 40.

[0075] Figure 35 The image shows the 1H NMR spectrum of the product after degradation in Example 41.

[0076] Figure 36 The image shows the 1H NMR spectrum of the product after degradation in Example 42.

[0077] Figure 37 The image shows the 1H NMR spectrum of the product after degradation in Example 43.

[0078] Figure 38 The image shows the 1H NMR spectrum of the product after degradation in Example 44.

[0079] Figure 39 The image shows the 1H NMR spectrum of the product after degradation in Example 45.

[0080] Figure 40 The image shows the 1H NMR spectrum of the product after degradation in Example 46.

[0081] Figure 41 This is a superimposed 1H NMR spectrum of the starting materials, polymer, and degradation products of Example 47.

[0082] Figure 42 The raw GPC data for polyHL_160 prepared in Example 23.

[0083] Figure 43 The raw GPC data for polyHL_319 prepared in Example 23.

[0084] Figure 44 The raw GPC data for polyHL_562 prepared in Example 23. Detailed Implementation

[0085] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0086] This invention aims to propose, for the first time, a monomer-recoverable cyclic polymer and its synthesis method. Using heterocyclic lactones as raw materials, the cyclic polymer is prepared through anionic ring-opening polymerization of these lactones. The synthesis method allows for the control of the degree of polymerization of the cyclic polymer, thereby controlling the polymer's Mn (number average molecular weight) and... (Molecular weight distribution). This invention also provides a series of methods for recovering cyclic polymer monomers. The synthetic method described in this invention can prepare cyclic polymers using readily available raw materials; for example, when the raw material heterocyclic lactone is 3,6-diethyltetrahydro-2H-pyran-2-one (HL), the HL can be prepared by a two-step palladium-catalyzed method using CO2, H2 and the inexpensive bulk chemical 1,3-butadiene, i.e., by synthesizing an unsaturated lactone δ-lactone with two C-C double bonds in the side chain through CO2 and 1,3-butadiene, and the δ-lactone reacts with hydrogen in the presence of a transition metal catalyst to obtain HL, as shown in the reaction route (1); the obtained HL is then subjected to an organic base (such as t Bu-P4) catalyzed anionic ring-opening polymerization (AROP) yields the cyclic polymer polyHL, which can be further cleaved by the catalytic method of this invention to obtain the monomer HL.

[0087]

[0088] Reaction route (1) Synthetic route of cyclic polymer polyHL

[0089] This invention provides a cyclic polymer comprising repeating units as shown in Formula 4:

[0090]

[0091] R1 and R2 can be the same or different, and both must exist simultaneously.

[0092] R1 and R2 are each independently selected from any one of hydrogen, halogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, monocyclic aromatic, substituted monocyclic aromatic, polycyclic aromatic, substituted polycyclic aromatic, polyheterocyclic aromatic, and substituted polyheterocyclic aromatic; the monocyclic aromatic is selected from phenyl, azirroaromatic, thioaromatic, and oxaaromatic; the polycyclic aromatic and polyheterocyclic aromatics refer to groups containing two or more monocyclic aromatics.

[0093] The halogen is selected from fluorine, chlorine, bromine, and iodine.

[0094] The alkyl group is a linear alkyl group, a branched alkyl group, or a cycloalkyl group; further, the alkyl group can be a C1-C20 alkyl group; or it can be a C1-C10 alkyl group, including methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl; preferably, it is ethyl.

[0095] The substituted alkyl group is a substituted linear alkyl group, a branched alkyl group, or a cycloalkyl group.

[0096] The substituents on the alkyl, alkenyl, alkynyl, monocyclic aromatic, polycyclic aromatic, and polyheterocyclic aromatic groups are monosubstituted or polysubstituted, and are independently selected from one or more of the following groups: hydrogen, heteroatom, amino, cyano, benzyl, alkyl carbonyl, alkenyl carbonyl, cycloalkyl carbonyl, phenyl carbonyl, benzyl carbonyl, alkoxy carbonyl, ester, sulfoxide, alkenyl, alkynyl, cycloalkyl, sulfone, hydroxyl, nitro, halogen, carboxyl, alkyl, alkoxy, amino, cycloalkoxy, cycloamino, sulfinamide, sulfonamide, morpholino, and piperazine. Furthermore, the substituents on the alkyl, alkenyl, alkynyl, monocyclic aromatic, polycyclic aromatic, and polyheterocyclic aromatic groups are monosubstituted or polysubstituted, and are independently selected from one or more of the following groups: hydrogen, heteroatom, amino, cyano, hydroxyl, nitro, halogen, carboxyl, C1-C10 alkyl, alkoxy, amino, cycloalkoxy, cycloamino, C2-C12 alkenyl, C2-C12 alkynyl, C3-C12 cycloalkyl, benzyl, alkyl carbonyl, C2-C12 alkenyl carbonyl, C3-C12 cycloalkyl carbonyl, phenyl carbonyl, benzyl carbonyl, alkoxy carbonyl, ester, sulfoxide, sulfone, sulfinamide, sulfonamide, morpholinyl, and piperazine.

[0097] Preferably, R1 is a C1-C20 alkyl group, and R2 is selected from C1-C20 alkyl groups; more preferably, R1 is a C1-C10 alkyl group, and R2 is selected from C1-C10 alkyl groups, and R1 and R2 can be C1, C2, C3, C4, C5, C6, C7, C8, C9, or C10 alkyl groups, respectively. Even more preferably, R1 and R2 are both ethyl groups.

[0098] X is selected from heteroatoms, including heteroatoms such as O, S, N, and P; preferably, X is O.

[0099] n is a positive integer greater than or equal to 1; for example, n can be 1-100, 100-1000, 1000-5000, 5000-10000, 10000-15000, 15000-20000, 20000-30000, 30000-40000, 40000-50000, 50000-100000, 100000-200000, etc.

[0100] Preferably, the cyclic polymer structure is as shown in Formula 2:

[0101]

[0102] R1, R2, X, and n are defined as described in compound 4 above.

[0103] The present invention also provides a method for synthesizing a cyclic polymer, the method comprising the steps of: synthesizing a cyclic polymer of formula 2 from a heterocyclic lactone of formula 1 under the condition of an organic base as a catalyst; the reaction process is shown in reaction formula (I).

[0104]

[0105] In reaction formula (I), R1 and R2 can be the same or different, and in formula 1, the two groups R1 and R2 must exist simultaneously on a six-membered heterocycle, and the substitution sites are any two of the four methylene carbons.

[0106] In Formulas 1 and 2, R1 and R2 are independently selected from any one of hydrogen, halogen, alkyl (linear alkyl, branched alkyl, cycloalkyl), substituted alkyl (linear alkyl, branched alkyl, cycloalkyl), alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, monocyclic aromatic, substituted monocyclic aromatic, polycyclic aromatic, substituted polycyclic aromatic, polyheterocyclic aromatic, and substituted polyheterocyclic aromatic; the monocyclic aromatic includes phenyl, azirroaromatic, thioaromatic, and oxaaromatic; the polycyclic aromatic and polyheterocyclic aromatic refer to groups containing two or more monocyclic aromatic groups; R1 and R2 may be the same or different, and must coexist.

[0107] The halogen is selected from fluorine, chlorine, bromine, and iodine.

[0108] The alkyl group is a linear alkyl group, a branched alkyl group, or a cycloalkyl group; further, the alkyl group can be a C1-C20 alkyl group; or it can be a C1-C10 alkyl group, including methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl; preferably, it is ethyl.

[0109] The substituted alkyl group is a substituted linear alkyl group, a branched alkyl group, or a cycloalkyl group.

[0110] The substituents on the alkyl, alkenyl, alkynyl, monocyclic aromatic, polycyclic aromatic, and polyheterocyclic aromatic groups are monosubstituted or polysubstituted, and are independently selected from one or more of the following groups: hydrogen, heteroatom, amino, cyano, benzyl, alkyl carbonyl, alkenyl carbonyl, cycloalkyl carbonyl, phenyl carbonyl, benzyl carbonyl, alkoxy carbonyl, ester, sulfoxide, alkenyl, alkynyl, cycloalkyl, sulfone, hydroxyl, nitro, halogen, carboxyl, alkyl, alkoxy, amino, cycloalkoxy, cycloamino, sulfinamide, sulfonamide, morpholino, and piperazine. Furthermore, the substituents on the alkyl, alkenyl, alkynyl, monocyclic aromatic, polycyclic aromatic, and polyheterocyclic aromatic groups are monosubstituted or polysubstituted, and are independently selected from one or more of the following groups: hydrogen, heteroatom, amino, cyano, hydroxyl, nitro, halogen, carboxyl, C1-C10 alkyl, alkoxy, amino, cycloalkoxy, cycloamino, C2-C12 alkenyl, C2-C12 alkynyl, C3-C12 cycloalkyl, benzyl, alkyl carbonyl, C2-C12 alkenyl carbonyl, C3-C12 cycloalkyl carbonyl, phenyl carbonyl, benzyl carbonyl, alkoxy carbonyl, ester, sulfoxide, sulfone, sulfinamide, sulfonamide, morpholinyl, and piperazine.

[0111] Preferably, R1 is a C1-C20 alkyl group, and R2 is selected from C1-C20 alkyl groups; more preferably, R1 is a C1-C10 alkyl group, and R2 is selected from C1-C10 alkyl groups, and R1 and R2 can be C1, C2, C3, C4, C5, C6, C7, C8, C9, or C10 alkyl groups, respectively. Even more preferably, R1 and R2 are both ethyl groups.

[0112] In reaction formula (I), X is selected from heteroatoms, including heteroatoms such as O, S, N, and P; preferably, X is O.

[0113] In reaction formula (I), the value of n represents the number of repeating units, and n is a positive integer greater than or equal to 1; for example, n can be 1-100, 100-1000, 1000-5000, 5000-10000, 10000-15000, 15000-20000, 20000-30000, 30000-40000, 40000-50000, 50000-100000, 100000-200000, etc.

[0114] In reaction formula (I), the organic base can be a sterically hindered or non-nucleophilic base.

[0115] Preferably, the organic base is an amine compound or a nitrogen-containing heterocyclic compound; the amine compound has the following formula:

[0116]

[0117] And the ammonium salt has the formula R11 R 12 R 13 N + H, where R 11 R 12 and R 13 Each of these groups represents hydrogen (H), a C1-C20 alkyl, a C5-C20 cycloalkyl, or a C7-C20 alkylaryl group, and each group may optionally contain one or more heteroatoms (e.g., oxygen, phosphorus, or sulfur atoms) and / or substituents, and R 11 and R 12 Between, R 12 and R 13 Between, and / or R 11 and R 13 Rings may exist between them, and the rings may contain heteroatoms.

[0118] Preferably, the organic base is selected from one or more of phosphazenes, compounds containing a guanidine group, and compounds containing an amidine group. In some embodiments, the organic base is selected from... t Bu-P1、 t Bu-P2, t Bu-P4, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-diazabicycloundec-7-ene (DBU), diethylamine, dimethylamine, triethylamine, N,N-diisopropylethylamine, N-methylmorpholine, n-octylamine, tri-n-butylamine, laurylamine, stearylamine, tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH), sodium or potassium alkoxides of C1-C5, triethanolamine, choline, N-methylmorpholine, pyridine, dimethylaminopyridine, N,N'-dihydroxyethylethylenediamine, β-hydroxyethylethylenediamine, N-(2-hydroxyethyl)ethylenediamine, N,N,N',N'-tetrahydroxyethylethylenediamine, N-hydroxyethylpropanediamine, trimethylhydroxyethylpropanediamine, N,N'-di(2-hydroxyethyl)-1,3-propanediamine, etc.

[0119] Preferably, the catalyst is one or more of phosphazene and TBD. More preferably, the phosphazene is a strong Lewis base containing a (R₂N)₂-P=N structure. Even more preferably, the phosphazene has the structure shown in Formula 3:

[0120]

[0121] In Equation 3, R3-R 10 Each alkyl group is independently selected from alkyl groups, preferably C1-C10 alkyl groups, such as C1 (methyl), C2 (ethyl), C3 (propyl, isopropyl), C4 (butyl, tert-butyl), C5, C6, C7, C8, C9, and C10 alkyl groups.

[0122] y is a positive integer greater than or equal to 1. Preferably, 1 ≤ y ≤ 3.

[0123] Preferably, the phosphazene is selected from... t Bu-P1、 t Bu-P2, t The structures of Bu-P4 are shown below:

[0124]

[0125] In the method of the present invention, the molar ratio of Formula 1 and the catalyst is (10-500):(0.01-5); preferably, it is (20-40):(0.1-4), more preferably, it is (30-350):(0.3-3), even more preferably, it is (40-300):(0.8-1.5), and even more preferably, it is (50-260):1; for example, it can be 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, 110:1, 120:1, 130:1, 140:1, 150:1, 160:1, 170:1, 180:1, 190:1, 200:1, 210:1, 220:1, 230:1, 240:1, 250:1, or 250:1.

[0126] The method described in this invention can be carried out under solvent-free conditions (i.e., bulk conditions) and solvent conditions.

[0127] When carried out under solvent conditions, the solvent for the reaction is selected from one or more of the following: tetrahydrofuran (THF), TBD, benzene, toluene, xylene, dichlorobenzene, mesitylene, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydropyrrole, tetrahydropyran, hexahydropyridine, ethyl acetate, diethyl ether, dimethyl ether, methyl ethyl ether, n-hexane, cyclohexane, cyclopentane, acetonitrile, dioxane, N,N-dimethylformamide, dimethyl sulfoxide, etc.; preferably, the solvent for the reaction is THF and / or TBD. More preferably, the solvent is THF.

[0128] In the method described in this invention, the initial concentration [M]0 of the heterocyclic lactone shown in formula (1) is not particularly limited, as long as the preparation of the cyclic polymer can be achieved. In some embodiments, the initial concentration [M]0 of the heterocyclic lactone shown in formula (1) is 0.1-20 mol / L. -1 For example, it could be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 mol L -1 Preferably, the concentration is 0.4-16 mol / L. -1 More preferably, it is 0.6-12 mol L. -1More preferably, it is 1.2-8 mol L. -1 For example, it could be 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, 5.0, 5.2, 5.4, 5.6, 5.8, 6.0, 6.2, 6.4, 6.6, 6.8, 7.0, 7.2, 7.4, 7.6, 7.8, 8.0 mol L -1 In some preferred embodiments, the initial concentration [M]0 of the heterocyclic lactone is 3-6 mol / L. -1 In some other preferred embodiments, the initial concentration [M]0 of the heterocyclic lactone is 4-5 mol / L. -1 In some other preferred embodiments, the initial concentration [M]0 of the heterocyclic lactone is 4.0 mol L. -1 .

[0129] In the method described in this invention, the reaction temperature is not particularly limited, as long as the preparation of the cyclic polymer can be achieved. In some embodiments, the reaction temperature is -100 to 220°C, and can be -100 to 180, -80 to 200, -100 to 150, -100 to 130, -100 to 120, -100 to 100°C, -80 to 80, -70 to 70, -60 to 60, -50 to 50, -50 to 60, -40 to 40, -30 to 30, -20 to 20, or -10 to 10°C. Preferably, it is -80 to 80°C. More preferably, it is -50 to 60°C. More preferably, the temperature is -50 to 30°C, for example, it can be -50, -49, -48, -47, -46, -45, -44, -43, -42, -41, -40, -39, -38, -37, 36, -35, -34, -33, -32, -31, -30, -29, -28, -27, -26, -25, -24, -23, -22, -21, -20, -19 -18, -17, -16, -15, -14, -13, -12, -11, -10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30℃. In some preferred embodiments, the reaction temperature is -30 to -10℃. In some preferred embodiments, the reaction temperature is -25℃.

[0130] In the method described in this invention, the reaction time is not particularly limited, as long as the preparation of the cyclic polymer can be achieved. In some embodiments, the reaction time is 5s-400h; it can be 10s-380h, 20s-36h, or even 40h. h, 40s-320h, 1min-300h, 1min-280h, 1min-260h, 1min-240h, 1min-220h, 1min-200h, 1min-180h, 1min-160h, 1min-140h, 1min-120h, 1min-10 0h, 1min-80h, 1min-60h, 1min-40h, 5min-40h, 11min-40h, 16min-40h, 1min-40h, 1min-40h, 1min-40h, 1min-40h, 1min-40h, 5min-100h, 2min- 260h, 3min-240h, 4min-220h, 5min-200h, 10min-180h, 30min-160h, 1h-150h, 1h-120h, 1h-100h, 1h-80h, 1h-60h, 1h-40h, 1h-20h, 1h-10h, 1h- 5h, 5h-100h, 5h-80h, 5h-60h, 5h-40h, 5h-20h, 5h-10h, 10h-100h, 10h- 80h, 10h-60h, 10h-40h, 10h-20h, 20h-60h, 20h-40h, 10h-30h, 10h-20h. Preferably, the reaction time is 10 min to 20 h, for example, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 30 min, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, or 20 h. In some preferred embodiments, the reaction time is 11 min; in other preferred embodiments, the reaction time is 16 min; in other preferred embodiments, the reaction time is 0.5 h; in other preferred embodiments, the reaction time is 2 h; in other preferred embodiments, the reaction time is 2.5 h; in other preferred embodiments, the reaction time is 3 h; in other preferred embodiments, the reaction time is 4 h; in other preferred embodiments, the reaction time is 6-8 h; in other preferred embodiments, the reaction time is 7 h; in other preferred embodiments, the reaction time is 10 h; and in other preferred embodiments, the reaction time is 12 h.

[0131] In the method described in this invention, when R1 is ethyl and R2 is ethyl, i.e., Formula 1 is HL, the catalyst is... t The reaction process of Bu-P4 is shown in the following reaction formula (II):

[0132]

[0133] The definition of n is as described above.

[0134] This invention [ t Bu-P4H] + Possible chain initiation mechanisms during the ring-opening polymerization of catalytic HL, such as Figure 8-10 As shown. HL and t Bu-P4 were mixed at room temperature in different molar ratios, and the reaction was analyzed by corresponding 1H and 31P NMR spectra. t Bu-P4H] + Characteristic signals and t The characteristic signals of Bu-P4 are monitored. t Bu-P4 can only deprotonate a very small portion of HL monomers.

[0135] This invention also provides a cyclic polymer prepared by the above method. The method allows for the control of the degree of polymerization of the cyclic polymer, thereby controlling the polymer's Mn (number-average molecular weight) and... (Molecular weight distribution). In some embodiments, the M of the cyclic polymer... n In 30-2000 kg mol -1 Between. In some embodiments, the M of the cyclic polymer n In 30-100kg mol -1 Between. In some embodiments, the M of the cyclic polymer n In 100-200 kg mol -1 Between. In some embodiments, the M of the cyclic polymer n In 200-400 kg mol -1 Between. In some other preferred embodiments, the M of the cyclic polymer. n At 500-600 kg mol -1 Between. In some other preferred embodiments, the M of the cyclic polymer. n In 500-800 kg mol -1 Between. In some other preferred embodiments, the M of the cyclic polymer. n In 400-1500 kg mol -1 Between. In some other preferred embodiments, the M of the cyclic polymer. nIn 300-2000 kg mol -1 between.

[0136] This invention also provides applications of the cyclic polymer shown in Formula 2 or the cyclic polymer prepared by the above method in the preparation of any one or more of polymer films, pressure-sensitive adhesives (such as tapes), and thermoplastic elastomers; wherein the pressure-sensitive adhesive can be further used to prepare products such as tapes. In some embodiments, the polymer film is colorless, transparent, and has good flexibility and viscoelasticity. In some embodiments, the tape is colorless, transparent, and has good flexibility and viscoelasticity.

[0137] This invention also provides a polymer product made from the cyclic polymer described above. The polymer product includes, but is not limited to, polymer films and tapes. The tapes can be transparent tapes, opaque tapes, single-sided tapes, double-sided tapes, protective tapes, heat-insulating tapes, high-temperature tapes, masking tapes, electrical tapes, electroplating tapes, packaging tapes, cloth tapes, fiber tapes, PE foam tapes, kraft paper tapes, protective film tapes, and specialty tapes, etc. In some preferred embodiments, the polymer product is a polymer film, which is colorless and transparent, and has good flexibility and viscoelasticity (peel strength). In other preferred embodiments, the polymer product is a transparent tape. In still other preferred embodiments, the polymer product is a 3M commercially available transparent tape.

[0138] This invention also provides the use of organic bases, such as phosphazenes, in the catalytic synthesis of cyclic polymers of Formula 2 from compounds of Formula 1 as described above. The organic base may be a sterically hindered or non-nucleophilic base.

[0139] Preferably, the organic base is an amine compound or a nitrogen-containing heterocyclic compound; the amine compound has the following formula:

[0140]

[0141] And the ammonium salt has the formula R 11 R 12 R 13 N + H, where R 11 R 12 and R 13 Each of these groups represents hydrogen (H), a C1-C20 alkyl, a C5-C20 cycloalkyl, or a C7-C20 alkylaryl group, and each group may optionally contain one or more heteroatoms (e.g., oxygen, phosphorus, or sulfur atoms) and / or substituents, and R 11 and R 12 Between, R 12 and R 13 Between, and / or R 11 and R13 Rings may exist between them, and the rings may contain heteroatoms.

[0142] Preferably, the organic base is selected from one or more of phosphazenes, compounds containing a guanidine group, and compounds containing an amidine group. In some embodiments, the organic base is selected from... t Bu-P4, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-diazabicycloundec-7-ene (DBU), diethylamine, dimethylamine, triethylamine, N,N-diisopropylethylamine, N-methylmorpholine, n-octylamine, tri-n-butylamine, laurylamine, stearylamine, tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH), sodium or potassium alkoxides of C1-C5, triethanolamine, choline, N-methylmorpholine, pyridine, dimethylaminopyridine, N,N'-dihydroxyethylethylenediamine, β-hydroxyethylethylenediamine, N-(2-hydroxyethyl)ethylenediamine, N,N,N',N'-tetrahydroxyethylethylenediamine, N-hydroxyethylpropanediamine, trimethylhydroxyethylpropanediamine, N,N'-di(2-hydroxyethyl)-1,3-propanediamine, etc.

[0143] Preferably, the organic base is one or more of phosphazene and TBD. More preferably, the phosphazene is a strong Lewis base containing a (R₂N)₂-P=N structure. Even more preferably, the phosphazene structure is as shown in Formula 3:

[0144]

[0145] In Equation 3, R3-R 10 Each alkyl group is independently selected from alkyl groups, preferably C1-C10 alkyl groups, such as C1 (methyl), C2 (ethyl), C3 (propyl, isopropyl), C4 (butyl, tert-butyl), C5, C6, C7, C8, C9, and C10 alkyl groups.

[0146] y is a positive integer greater than or equal to 1. For example, 1≤y≤10, 10≤y≤20; preferably, 1≤y≤3.

[0147] More preferably, the phosphazene is selected from... t Bu-P1、 t Bu-P2, t The structures of Bu-P4 are shown below:

[0148]

[0149] The present invention also provides a method for catalytic recovery of heterocyclic lactone monomers from cyclic polymers, the method comprising an inorganic salt pyrolysis catalysis method and a La[N(SiMe3)2]3 mild catalysis method.

[0150] In this invention, the pyrolysis catalytic method includes: using inorganic salts to catalytically degrade cyclic polymers as shown in Formula 2 to obtain heterocyclic compounds or oligomers of Formula 1 or corresponding derivatives of Formula 1.

[0151] The pyrolysis catalysis method can be carried out under solvent or solvent-free conditions.

[0152] When degradation is carried out in a solvent, the solvent may be selected from one or more of toluene, benzene, chlorobenzene, bromobenzene, dichlorobenzene, dibromobenzene, o-dichlorobenzene, o-dibromobenzene, m-dichlorobenzene, m-dibromobenzene, p-dichlorobenzene, p-dibromobenzene, toluene, m-xylene, p-xylene, o-xylene, mesitylene, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, etc. In some preferred embodiments, the solvent is toluene. In other preferred embodiments, the solvent is mesitylene. In still other preferred embodiments, the solvent is o-dichlorobenzene.

[0153] In this method, the pyrolysis catalysis does not impose any particular limitation on the initial concentration [M]0 of the cyclic polymer of formula (2), as long as the preparation of the cyclic polymer can be achieved. In some embodiments, the initial concentration [M]0 of the cyclic polymer of formula (2) is 1-50 mol / L. -1 For example, it could be 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50 mol L -1 Preferably, the concentration is 2-40 mol / L. -1 More preferably, 3-30 mol L -1 More preferably, it is 4-20 mol L. -1 In some preferred embodiments, the initial concentration [M]0 of the cyclic polymer is 3-6 mol / L. -1 In some other preferred embodiments, the initial concentration [M]0 of the heterocyclic lactone is 4.0 mol L. -1 .

[0154] The pyrolysis catalysis is performed using a hot bath method such as an oil bath or sand bath, with a temperature range of 100-350℃. Preferably, it is 110-300℃; more preferably, it is 120-240℃; and can be 120, 30, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, or 240℃. In some preferred embodiments, the pyrolysis catalysis temperature is 120℃. In some preferred embodiments, the pyrolysis catalysis temperature is 130℃. In some preferred embodiments, the pyrolysis catalysis temperature is 140℃. In some preferred embodiments, the pyrolysis catalysis temperature is 150℃. In some preferred embodiments, the pyrolysis catalysis temperature is 160℃. In some preferred embodiments, the pyrolysis catalysis temperature is 180℃.

[0155] The pyrolysis catalysis time is 6-45 hours; preferably, it is 8-36 hours, and can be 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, or 36 hours. In some preferred embodiments, the pyrolysis catalysis time is 10 hours. In some preferred embodiments, the pyrolysis catalysis time is 12 hours. In some preferred embodiments, the pyrolysis catalysis time is 16 hours. In some preferred embodiments, the pyrolysis catalysis time is 24 hours.

[0156] The physicochemical properties of the cyclic polymers to which the inorganic salt catalytic cracking method of this invention is applicable are not particularly limited. Any cyclic polymer obtained according to the method described above or other methods of this invention can be used to recover monomers using the cracking method of this invention. In some preferred embodiments, the inorganic salt catalytic cracking method of this invention is applicable to M... n In 300-2000 kgmol -1 A range of cyclic polymers. In some preferred embodiments, the inorganic salt catalytic cracking method of the present invention is suitable for M... n In 400-1500 kg mol -1 A range of cyclic polymers. In some preferred embodiments, the inorganic salt catalytic cracking method of the present invention is suitable for M... n In 500-800 kg mol -1 A range of cyclic polymers. In some preferred embodiments, the inorganic salt catalytic cracking method of the present invention is suitable for M... n At 500-600 kg mol -1 Cyclic polymers within a certain range. In some preferred embodiments, the inorganic salt catalytic cracking method described in this invention is applicable to the cyclic polymers prepared in Examples 1-17 of this invention.

[0157] Optionally, the pyrolysis catalysis is carried out in a nitrogen atmosphere.

[0158] Optionally, the pyrolysis catalysis is carried out under sealed conditions.

[0159] Optionally, the pyrolysis catalysis is carried out under vacuum conditions.

[0160] In this invention, the La[N(SiMe3)2]3 mild catalytic method includes: catalytically cracking the cyclic polymer as described above using La[N(SiMe3)2]3 under mild conditions to obtain the heterocyclic compound or its oligomer or the corresponding derivative of Formula 1.

[0161] The La[N(SiMe3)2]3 mild catalytic method can be carried out under solvent or solvent-free conditions.

[0162] When degradation is carried out in a solvent, the solvent may be selected from one or more of toluene, benzene, chlorobenzene, bromobenzene, dichlorobenzene, dibromobenzene, o-dichlorobenzene, o-dibromobenzene, m-dichlorobenzene, m-dibromobenzene, p-dichlorobenzene, p-dibromobenzene, toluene, m-xylene, p-xylene, o-xylene, mesitylene, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, etc. In some preferred embodiments, the solvent is toluene. In other preferred embodiments, the solvent is mesitylene.

[0163] The mild catalytic method does not impose any particular limitation on the initial concentration [M]0 of the cyclic polymer of formula (2), as long as the preparation of the cyclic polymer can be achieved. In some embodiments, the initial concentration [M]0 of the cyclic polymer of formula (2) is 1-50 mol / L. -1 For example, it could be 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50 mol L -1 Preferably, the concentration is 2-40 mol / L. -1 More preferably, 3-30 mol L -1 More preferably, it is 4-20 mol L. -1 In some preferred embodiments, the initial concentration [M]0 of the cyclic polymer is 3-6 mol / L. -1 In some other preferred embodiments, the initial concentration [M]0 of the heterocyclic lactone is 4.0 mol L. -1 .

[0164] The mild catalytic conditions are achieved through a hot bath method such as an oil bath or sand bath, with a temperature range of 40-90℃; preferably, 50-80℃, and can be 50, 55, 60, 65, 70, 75, or 80℃. In some preferred embodiments, the degradation temperature is 50℃. In some preferred embodiments, the degradation temperature is 60℃. In some preferred embodiments, the degradation temperature is 70℃. In some preferred embodiments, the degradation temperature is 80℃.

[0165] The mild catalytic time is 1-45 hours, and can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, or 45 hours. In some preferred embodiments, the degradation time is 3 hours. In some preferred embodiments, the degradation time is 6 hours. In some preferred embodiments, the degradation time is 9 hours. In some preferred embodiments, the degradation time is 12 hours. In some preferred embodiments, the degradation time is 15 hours. In some preferred embodiments, the degradation time is 18 hours. In some preferred embodiments, the degradation time is 21 hours. In some preferred embodiments, the degradation time is 24 hours.

[0166] The physicochemical properties of the cyclic polymers to which the mild catalytic method described in this invention is applicable are not particularly limited. Any cyclic polymer obtained according to the method described above or other methods can be used to recover monomers using the mild catalytic method of this invention. In some preferred embodiments, the mild catalytic method described in this invention is applicable to M... n In 300-2000 kg mol -1 A range of cyclic polymers. In some preferred embodiments, the mild catalytic method described in this invention is suitable for M. n In 400-1500 kgmol -1 A range of cyclic polymers. In some preferred embodiments, the mild catalytic method described in this invention is suitable for M. n In 500-800 kg mol -1 A range of cyclic polymers. In some preferred embodiments, the mild catalytic method described in this invention is suitable for M. n At 500-600 kg mol -1 A range of cyclic polymers. In some preferred embodiments, the mild catalytic method described herein is applicable to the cyclic polymers prepared in Examples 1-17 of this invention.

[0167] Optionally, the mild catalysis is carried out in a nitrogen atmosphere.

[0168] Optionally, the mild catalysis is carried out under sealed conditions.

[0169] Optionally, the mild catalysis is carried out under vacuum conditions.

[0170] In the recycling method described in this invention, when the catalytic polymer PolyHL recycles Poly monomers, the reaction process is shown in the following reaction route (2):

[0171]

[0172] It should be noted that the process equipment or apparatus not specifically specified in the following embodiments are all conventional equipment or apparatus in the art. Furthermore, it should be understood that one or more method steps mentioned in this invention do not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific specific embodiments, and not for limiting the scope of protection of the present invention; in the specification and claims of this invention, unless otherwise expressly stated herein, the singular forms "a," "an," and "this" include the plural forms.

[0173] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0174] The present invention does not limit the HL raw materials used in the following examples. They can be commercially available or prepared by the following method: CO2 and 1,4-butadiene are synthesized into δ-L under Pd catalysis, and δ-L and H2 are synthesized into the hexa-membered lactone 3,6-diethyltetrahydro-2h-pyran-2-one (HL) under Pd / C catalysis. The reaction process is shown in the following reaction route (3).

[0175]

[0176] In the following examples, the starting material is HL, and the cyclic compound polyHL is prepared by ring-opening polymerization of HL under the catalysis of an organic base. The reaction formula is as follows:

[0177]

[0178] Polymer number-average molecular weight Mn and molecular weight distribution Determination method: Take 200 μL of the reaction solution from the reaction system, remove the solvent by rotary evaporation, and determine the Mn (number average molecular weight) of the product by GPC method at 40 °C in a tetrahydrofuran mobile phase after calibration with PMMA standard sample. (Molecular weight distribution)

[0179] Examples 1-6: HL ring-opening polymerization catalyzed by tBu-P4

[0180] This invention uses three commonly used phosphazene bases: t Bu-P1、 t Bu-P2, t Using Bu-P4 as a catalyst, and controlling the [HL] / [phosphazene base] molar ratio at 50 / 1, the reaction was carried out in tetrahydrofuran (THF) at -25°C for 12 h. The results are shown in Table 1. Neither tBu-P1 nor tBu-P2 produced polymers after 12 h (Examples 1 and 2). Surprisingly, tBu-P4 achieved a maximum conversion rate of 88% after 12 h (Table 1), yielding a polyHL sample with an ultra-high molecular weight Mn of 613.8 kg mol⁻¹ and a moderate molecular weight distribution D of 1.45 (Example 3). Furthermore, this invention found that changing the concentration of tBu-P4 in the system affects the molecular weight Mn and the resulting polyHL. n It has only a small effect on the molecular weight distribution D (Examples 4-6).

[0181] In order to determine t The controllability of the ROP of HL catalyzed by Bu-P4 alone in a THF solution at -25°C ([HL] / [ t A kinetic experiment was conducted with the molar ratio of Bu-P4 = 50 / 1 and [M]0 = 4.0M. Figure 3 (See Table 2). The curve showing the change of ln[M]0 / [M] over time indicates that the initial conversion rate reaches 63% within 4 hours, after which the polymerization rate tends to slow down, reaching 84% within the next 6-8 hours. Figure 3 a). The time-dependent curve of ln[M]0 / [M] exhibits very clear first-order dynamic characteristics. Figure 3 b). Interestingly, polyHL's M n There was a clear linear correlation with the monomer conversion rate, but the dispersion widened significantly after the monomer conversion rate reached 50%. Figure 3 c). As the reaction time increases, the GPC curve gradually shows a bimodal distribution, possibly due to severe transesterification reactions occurring at high monomer conversion rates. Figure 3 d). These data indicate that high molecular weight polymers can be produced in a relatively controlled ROP manner if the reaction is quenched within 4 hours before the reaction begins.

[0182] Table 1. Experimental results of ring-opening polymerization of HL monomers using phosphazene alkaline catalysts

[0183]

[0184] Table 2. Kinetic experimental data of phosphazene base-catalyzed ring-opening polymerization

[0185]

[0186] Example 1

[0187] In a glove box under a nitrogen atmosphere, take 0.0126 mmol of... t The Bu-P1 catalyst was added to a flame-dried 10 mL Schlenk tube, followed by the addition of 0.025 mL of THF to dissolve the catalyst. The Schlenk tube was then sealed with a rubber stopper, wrapped with sealing film, and removed from the glove box. It was then placed in a pre-set -25°C cryogenic bath until temperature equilibrium was reached. Once equilibrium was achieved, 0.63 mmol of HL was rapidly injected into the Schlenk tube using a syringe, and the mixture was stirred for 12 h. Then, 1 mL of 5% HCl-methanol solution was added to quench the reaction, and 50 μL of the reaction solution was used for further processing. 1 The monomer conversion rate was analyzed by 1H NMR. The results are shown in Table 1.

[0188] Example 2

[0189] The preparation steps are the same as in Example 1, except that the catalyst is replaced with an equivalent amount t Bu-P2.

[0190] Example 3

[0191] The preparation steps are the same as in Example 1, except that the catalyst is replaced with an equivalent amount t Bu-P4. Specific steps include:

[0192] In a glove box under a nitrogen atmosphere, take 0.0126 mmol of... tThe Bu-P4 catalyst was added to a flame-dried 10 mL Schlenk tube, followed by the addition of 0.025 mL of THF to dissolve the catalyst. The Schlenk tube was then sealed with a rubber stopper, wrapped with sealing film, and removed from the glove box. It was then placed in a pre-set -25°C cryogenic bath until temperature equilibrium was reached. Once equilibrium was achieved, 0.63 mmol of HL was rapidly injected into the Schlenk tube using a syringe, and the mixture was stirred for 12 h. Then, 1 mL of 5% HCl-methanol solution was added to quench the reaction, and 50 μL of the reaction solution was used for further processing. 1 1H NMR analysis of monomer conversion rate.

[0193] To purify the polyHL product, the quenched reaction solution was added dropwise to 20 mL of ice-cold methanol. After centrifugation, the supernatant was discarded, and the precipitate was polyHL. This purification process was repeated 3-5 times. The precipitate obtained from the last purification was dried in a vacuum oven to constant weight; the resulting product was the purified polyHL sample under these conditions. Simultaneously, the molecular weight (M) of the product was determined. n (number average molecular weight) and (Molecular weight distribution)

[0194] Examples 4-6

[0195] The preparation steps are the same as in Example 3, except that the catalyst equivalent is adjusted from 2 mol% to 1 mol% (Example 4), 0.67 mol% (Example 5, where HL / catalyst is 150 / 1), and 0.5 mol% (Example 6), as detailed in Table 1.

[0196] Examples 7-17: Kinetics of Ring-Opening Polymerization of HL Catalyzed by tBu-P4

[0197] Polymer preparation method of Example 7

[0198] In a glove box under a nitrogen atmosphere, take 0.0126 mmol of... t The Bu-P4 catalyst was added to a flame-dried 10 mL Schlenk tube, followed by the addition of 0.058 mL of THF to dissolve the catalyst. The Schlenk tube was then sealed with a rubber stopper, wrapped with sealing film, and removed from the glove box. It was then placed in a pre-set -25°C cryogenic bath until temperature equilibrium was reached. Once equilibrium was achieved, 0.63 mmol of HL was rapidly injected into the Schlenk tube using a syringe, and the mixture was stirred for 11 min. Then, 1 mL of 5% HCl-methanol solution was added to quench the reaction, and 50 μL of the reaction solution was used for further processing. 1 ¹H NMR analysis was used to determine the monomer conversion. Simultaneously, the M of the product was determined. n (number average molecular weight) and (Molecular weight distribution)

[0199] Polymer preparation methods of Examples 8-17

[0200] The preparation steps are the same as in Example 7, except that the stirring reaction time was adjusted from 11 min to about 0.267 h (i.e. 16 min) (Example 8), 0.5 h (Example 9), 1 h (Example 10), 2 h (Example 11), 2.5 h (Example 12), 3 h (Example 13), 4 h (Example 14), 7 h (Example 15), 10 h (Example 16), and 12 h (Example 17).

[0201] Example 18: MALDI-TOF spectra of the synthesized cyclic polymer after rigorous removal of residual water using HL.

[0202] (1.1) Sample preparation for determination

[0203] In a glove box under a nitrogen atmosphere, take 0.0126 mmol of... t The Bu-P4 catalyst was added to a flame-dried 10 mL Schlenk tube, followed by the addition of 0.058 mL of THF to dissolve the catalyst. The Schlenk tube was then sealed with a rubber stopper, wrapped with sealing film, and removed from the glove box. It was placed in a pre-set -25°C cryogenic bath until temperature equilibrium was reached. Once equilibrium was achieved, 0.63 mmol of HL was rapidly injected into the Schlenk tube using a syringe, and the mixture was stirred for 3-5 min. Then, 1 mL of 5% HCl-methanol solution was added to quench the reaction. The quenched reaction solution was then added dropwise to 20 mL of ice-cold methanol. After centrifugation, the supernatant was discarded, and the precipitate was the test sample.

[0204] (1.2) MALDI-TOF spectral characterization

[0205] The sample to be tested prepared in step (1.1) of this embodiment was dried in a vacuum drying oven to constant weight. A small amount was taken out for MALDI-TOF measurement, and the measurement results are as follows. Figure 4 As shown, the results only show one set of signals that can be attributed to the cyclic polyHL mass peaks.

[0206] (1.3) 1 H and 13 C10 NMR spectral characterization

[0207] The cyclic polymer sample prepared in Example 3 was measured. 1 H and 13 The 13C NMR spectrum shows that no chain-terminal signal was observed, further supporting the view that the polymer structure is cyclic. Figure 5 , Figure 6 ).

[0208] MALDI-TOF spectra of the synthesized cyclic polymer in Example 19HL when residual water was not strictly removed.

[0209] (1.1) Sample preparation for determination

[0210] The preparation method is the same as (1.1) in Example 18, except that the HL monomer used was not subjected to strict dehydration. According to the Karl Fischer moisture analyzer, the water content of the HL monomer is about 100 ppm.

[0211] (1.2) MALDI-TOF spectral characterization

[0212] The sample to be tested was dried in a vacuum drying oven until constant weight. A small amount was then taken out for MALDI-TOF measurement. The measurement results are as follows: Figure 7 As shown in the figure, a water-induced linear mass peak can only be detected if residual water in the HL monomer or the preparation system is not strictly removed.

[0213] Example 20 t Possible chain initiation mechanism of Bu-P4 alone catalyzing the ROP of HL to form cyclic polyHL products

[0214] pass 1 1H NMR spectroscopy detection, catalyst t The ability of Bu-P4 to extract acidic H from HL was verified. HL and t Bu-P4 were mixed at room temperature in molar ratios of 1 / 1, 2 / 1, 4 / 1, and 8 / 1, respectively, and then subjected to appropriate... 1 H and 31 The reaction was monitored using P NMR spectroscopy.

[0215] The results are as follows Figure 8-10 As shown in the figure, [ t Bu-P4H] + The characteristic signal is: 1 In 1H NMR, the δ values ​​were 7.92–8.07 ppm; in 31N PMR, the δ values ​​were 12.48 ppm and -23.64 ppm, respectively; however, with HL / t The increase in the Bu-P4 ratio, [ t The Bu-P4H+ signal strength was only slightly enhanced. t The characteristic signals of Bu-P4 are: in 1H NMR, δ 1.72, 2.70, and 2.72 ppm; in 31NMR, δ 4.96 and -25.31 ppm. These data clearly indicate that... tBu-P4 can only deprotonate a very small portion of HL monomers, which may explain why... t The concentration of Bu-P4 and the M of the cyclic polyHL synthesized by the preparation system described in this invention. n The reasons for the lack of direct correlation between them are explained above.

[0216] (1) HL and at different ratios t Bu-P4 mixed experiment ( 31 (P NMR spectrum)

[0217] Figure 8 Experimental method: In a glove box under a nitrogen atmosphere, weigh out the following... Figure 8 medium equivalent t Bu-P4 catalyst was dissolved in 0.6 mL of dry deuterated toluene. A measured equivalent of HL monomer was then added to the solution, and after slight stirring, the solution was transferred to a flame-dried J-Young NMR tube and immediately characterized by NMR spectroscopy. The results are as follows: Figure 8 As shown.

[0218] (2) HL and at different ratios t Bu-P4 mixed experiment ( 1 (H NMR spectrum)

[0219] Figure 9-10 Experimental method: In a glove box under a nitrogen atmosphere, weigh out the following... Figure 9-10 medium equivalent t Bu-P4 catalyst was dissolved in 0.6 mL of dry deuterated toluene. A measured equivalent of HL monomer was then added to the solution, and after stirring for the time shown in the figure, the solution was transferred to a flame-dried J-Young NMR tube, and NMR spectroscopy characterization was performed immediately. The results are as follows: Figure 9-10 As shown.

[0220] Example 21 t The difference in Gibbs free energy of Bu-P4 extracting protons from BnOH, HL, and H2O

[0221] This invention uses quantum mechanical calculations to evaluate t The Gibbs free energy of Bu-P4 abstracting a proton from the HL monomer to form a cyclic polymer, and... t The difference in Gibbs free energy between Bu-P4 and BnOH and water molecules was used to calculate and verify the feasibility of the process for generating cyclic polyHL via deprotonation. The reaction process and free energy data are as follows: Figure 11As shown, the Gibbs free energy order for the deprotonation reaction is BnOH (3.9 kcal mol⁻¹). <HL(5.7kcal mol-1)<H2O(9.3kcal mol -1 This indicates that BnO - It is the initiator that most readily produces active species, and the energy required for HL to produce active species is only 1.8 kcal / mol higher than that of BnOH. -1 This indicates that HL is in t Cyclic polyHL can be generated through a deprotonation mechanism under Bu-P4 catalysis.

[0222] Example 22 Physical properties of cyclic polyHL

[0223] (1) Sample preparation for determination

[0224] In a glove box under a nitrogen atmosphere, take 0.063 mmol of... t The Bu-P4 catalyst was added to a flame-dried 10 mL Schlenk tube, followed by 0.058 mL of THF to dissolve the catalyst. The Schlenk tube was then sealed with a rubber stopper, wrapped with sealing film, and removed from the glove box. It was placed in a pre-set -25°C cryogenic bath until temperature equilibrium was reached. Once equilibrium was achieved, 0.63 mmol of HL was rapidly injected into the Schlenk tube using a syringe, and the mixture was stirred for 30 min. Then, 1 mL of 5% HCl-methanol solution was added to quench the reaction. To purify the polyHL product, the quenched reaction solution was added dropwise to 20 mL of ice-cold methanol. After centrifugation, the supernatant was discarded, and the precipitate was polyHL. This purification process was repeated 3-5 times. After the final precipitate was obtained, it was dried in a vacuum oven to constant weight. The resulting product was the purified polyHL sample. The molecular weight (M) of the product was also determined. n (number average molecular weight) and (Molecular weight distribution), the result is M n =21.7 kg / mol, D = 1.13.

[0225] (2) Analysis by thermogravimetric analysis (TGA), derivative thermogravimetric analysis (DTG), and differential scanning calorimetry (DSC) t Thermal stability of cyclic polyHL prepared in the Bu-P4 system

[0226] The results are as follows Figure 12-13 As shown. By Figure 12 It can be seen that cyclic polyHL exhibits excellent thermal stability (Td, 5% > 325℃). The TGA and DTG curves of this product show that its Td... d,5％ =332.3℃, Tmax=367.3℃; from Figure 13 It can be seen that the second heating scan curve (5℃ min) of the annular polyHL sample -1 The DSC curve of ) shows its glass transition temperature (T) g The temperature was -29.7℃, and no crystallization peak was observed.

[0227] The results show that polyHL is an amorphous polymer material with good thermal stability.

[0228] Example 23: Determination of peel performance of polyHL polymers with different molecular weights

[0229] (1) Preparation of cyclic polymer samples

[0230] t Ring-opening polymerization of HL catalyzed solely by Bu-P4 can yield high molecular weight polyHL, providing a promising pathway for obtaining pressure-sensitive adhesives with potential applications. This example uses a simple 180° peel test to determine the peel strength of polyHL with different molecular weights. The preparation processes are as follows:

[0231] polyHL_160 (molecular weight M) n Preparation of 160) cyclic polymer samples: In a glove box under nitrogen atmosphere, take 0.025 mmol of... t The Bu-P4 catalyst was added to a flame-dried 10 mL Schlenk tube, followed by the addition of 0.025 mL of THF to dissolve the catalyst. The Schlenk tube was then sealed with a rubber stopper, wrapped with sealing film, and removed from the glove box. It was then placed in a pre-set -25°C cryogenic bath until temperature equilibrium was reached. Once equilibrium was achieved, 1.26 mmol of HL was rapidly injected into the Schlenk tube using a syringe, and the mixture was stirred for 60 min. Finally, 1 mL of 5% HCl-methanol solution was added to quench the reaction.

[0232] To purify the polyHL product, the quenched reaction solution was added dropwise to 20 mL of ice-cold methanol. After centrifugation, the supernatant was discarded, and the precipitate was polyHL. This purification process was repeated 3-5 times. The precipitate obtained in the last step was dried in a vacuum oven to constant weight, yielding the polyHL_160 sample. Its raw GPC data can be found here. Figure 42 As shown, the M of polyHL_160 was measured simultaneously. n and

[0233] polyHL_319 (molecular weight M) nPreparation of cyclic polymer samples (319): The preparation steps were the same as in Example polyHL_160, except that the catalyst equivalent was changed to 0.013 mmol and the reaction time was changed to 4 h, resulting in polyHL_319 samples. The raw GPC data are shown below. Figure 43 As shown, the M of polyHL_319 was simultaneously measured. n and

[0234] polyHL_562 (molecular weight M) n Preparation of cyclic polymer samples (562): The preparation steps were the same as in Example polyHL_160, except that the catalyst equivalent was changed to 0.0063 mmol and the reaction time was changed to 6 h, resulting in sample polyHL_562. Its raw GPC data can be found in [link to GPC data]. Figure 43 As shown, the M of polyHL_562 was simultaneously measured. n and

[0235] (2) Polymer peel performance test

[0236] A glass slide was used as the rigid substrate, and A4 paper (15×2.6cm) was used as the surface substrate. Figure 14 a) The polyHL sample was uniformly coated onto a glass slide using a coating blade (with 3M 665, 3M810, and 3M1600 as controls). Cross-sectional scanning electron microscopy (SEM) showed a uniform film thickness of 36.9 ± 1.2 μm. Figure 14 b). The experiment was conducted at 25°C on an Instron 5966 universal mechanical testing instrument, with a peel angle of 180° and a peel speed of 10 mm / min. -1 We are pleased to find that polyHL_319,562, and 160 (the numbers refer to the molecular weight M of polyHL)... n The concentrations were 319, 562, and 160 kg mol, respectively. -1 The adhesion forces of the samples were 3.8±0.12, 3.5±0.20, and 1.5±0.65 N / cm, respectively. -1 ( Figure 14 (c and Table 3). Under the same test conditions, the peel strength of polyHL_319 and polyHL_562 was higher than that of polyHL_319 and polyHL_562. Scotch commercial transparent tape ( 665 is 2.4 ± 0.40 N / cm. -1 ; 810 is 1.9 ± 0.31 N cm. -1 ) and vinyl electrical tape ( 1600 is 0.8 ± 0.17 N / cm. -1The peel strength of PolyHL_160 is 1.5 ± 0.65 N / cm. -1 ,and Scotch Commercial Transparent Tape 810 is equivalent.

[0237] (3) Measurement of transmittance, flexibility and viscoelasticity

[0238] To demonstrate the transmittance and color of polyHL, a high MW polymer sample (M n = 613.8 kg mol -1 (D=1.45, Example 3) A transparent, colorless polymer film was formed on a PTFE mold by solution casting, and the film exhibited good flexibility and viscoelasticity. Figure 14 d).

[0239] Table 3. 180° peel performance test data of the ring-shaped polyHL sample and three commercially available tapes (the same sample was measured three times).

[0240]

[0241] Examples 24-38: Chemical recovery experiments of cyclic polyHL polymers under high temperature conditions

[0242] The chemical recyclability of the polyHL sample prepared in Example 4 was determined, and its M... n At 500-600 kg mol -1 Within the range, it is 571.5 kg mol. -1 .

[0243] First, several trifluoromethanesulfonic acid metal salts, including AgCF3SO3, Cu(CF3SO3)2, Fe(CF3SO3)3, Sc(CF3SO3)3, and Y(CF3SO3)3, were used to catalytically depolymerize polyHL (toluene solution, initial concentration of HL [M]0 = 0.5M) at 120°C for 24 h in a closed reaction tube (Examples 24-28). However, only Fe(CF3SO3)3 and Sc(CF3SO3)3 could recover the HL monomer, with recoveries of 53% and 27%, respectively (Examples 26, 27).

[0244] Then, based on Example 24, recovery experiments were conducted by changing the catalyst, solvent, and reaction temperature. Specific experimental conditions are shown in Table 1. The results showed that only FeCl2 could recover the HL monomer, with a recovery rate of 21% (Example 29); Sn(Oct)2 had a recovery rate of only 5%; while Fe(acac)2, DBTDL, and tBu-P4 showed no significant reactivity even after heating at 150°C for 12 hours (Examples 29-33).

[0245] Next, using ZnCl2 as a catalyst, the reaction was carried out in toluene at 130°C, 140°C, and 150°C for 12 h. It was observed that the monomer recovery rate gradually increased with increasing temperature (Examples 34-36; 31%, 39%, and 54%). Interestingly, when using the more polar solvent o-dichlorobenzene at 150°C and 160°C, the monomer recovery rate significantly increased to 91% and 100%, respectively (Examples 37-38), achieving 100% chemical recovery of the ZnCl2 catalyst.

[0246] Table 4. Chemical recovery experiments of cyclic polyHL samples

[0247]

[0248] Example 24

[0249] In a glove box under a nitrogen atmosphere, 200 mg of cyclic polyHL sample (prepared in Example 14) and 5 mol% AgCF3SO3 were placed in a 25 mL Schlenk tube, and then 2.6 mL of toluene was added to dissolve them. The Schlenk tube was then sealed with a rubber stopper, wrapped with sealing film, removed from the glove box, and placed in a pre-set 120°C oil bath for heating and stirring for 24 hours. The solvent was then removed from the system, and 10 mg of the degradation product was taken out for further processing. 1 HL yield was analyzed by 1H NMR.

[0250] Examples 25-28

[0251] The experimental conditions were the same as in Example 24, except that AgCF3SO3 was replaced with Cu(CF3SO3)2 (Example 25), Fe(CF3SO3)3 (Example 26), Sc(CF3SO3)3 (Example 27), and Y(CF3SO3)3 (Example 28).

[0252] Examples 29-33

[0253] The experimental conditions were the same as in Example 24, except that the catalyst type was changed, the reaction temperature was increased to 150°C, the reaction time was shortened to 12 h, and the solvent was replaced with mesitylene. The catalyst types were: FeCl2 (Example 29), Fe(acac)2 (Example 30), Sn(Oct)2 (Example 31), and DBTDL (Example 32). t Bu-P4 (Example 33).

[0254] Example 34

[0255] In a glove box under a nitrogen atmosphere, 200 mg of cyclic polyHL sample (prepared in Example 14) and 5 mol% ZnCl2 were placed in a 25 mL Schlenk tube, and then 2.6 mL of toluene was added to dissolve them. The Schlenk tube was then sealed with a rubber stopper, wrapped with sealing film, removed from the glove box, and placed in a pre-set 130°C oil bath for heating and stirring for 12 hours. The solvent was then removed from the system, and 10 mg of the degradation product was taken out for further processing. 1 HL yield was analyzed by 1H NMR.

[0256] Examples 35-36

[0257] The experimental conditions were the same as in Example 34, except that the reaction temperature was increased to 140°C (Example 35) and 150°C (Example 36).

[0258] Examples 37-38

[0259] The experimental conditions were the same as in Example 34, except that the reaction temperature and solvent were changed: 150°C, o-dichlorobenzene (Example 37), 160°C, o-dichlorobenzene (Example 38).

[0260] Examples 39-47: Chemical recovery experiments of cyclic polyHL polymers under mild conditions

[0261] To further reduce the energy input during the chemical cycle, the catalytic activity of IMes, DBU, TBD, and La(La[N(SiMe3)2]3) was also measured. At 50°C (toluene as solvent, [HL]0 = 0.5 M), only La[N(SiMe3)2]3 exhibited excellent HL recovery: 47% at 3 h, 81% at 12 h, and 88% at 24 h (Examples 39-41).

[0262] When the [HL]0 in the above system was diluted to 0.1 M, no significant increase in recovery was observed (Examples 42-43). To achieve complete recovery of the HL monomer, the reaction temperature was increased to 80°C in a toluene solution of [HL]0 = 0.5 M. At this temperature, the recovery rate of the HL monomer reached 85% within 3 hours and remained unchanged within 12 hours (Examples 44-45), indicating that the depolymerization process was faster than at 50°C. Then, the system was diluted to 0.1 M at 80°C, and the recovery rate of the HL monomer reached 93% within 3 hours (Example 46), and finally reached 100% within 12 hours (Example 47).

[0263] Table 5. Mild-condition degradation experiments of cyclic polyHL

[0264]

[0265] Example 39

[0266] In a glove box under a nitrogen atmosphere, 200 mg of cyclic polyHL sample (prepared in Example 14) and 3 mol% La[N(SiMe3)2]3 were placed in a 25 mL Schlenk tube, and then 2.6 mL of toluene was added to dissolve them. The Schlenk tube was then sealed with a rubber stopper, wrapped with sealing film, removed from the glove box, and placed in a pre-set 50°C oil bath for heating and stirring for 3 hours. The solvent was then removed from the system, and 10 mg of the degradation product was taken out for further processing. 1 HL yield was analyzed by 1H NMR.

[0267] Examples 40-43

[0268] The experimental conditions were the same as in Example 39, except that the amount of reaction solvent added and / or the reaction time were changed: 2.6 mL toluene, 12 h (Example 40); 2.6 mL toluene, 24 h (Example 41); 12.8 mL toluene, 3 h (Example 42); 12.8 mL toluene, 24 h (Example 43).

[0269] Example 44

[0270] In a glove box under a nitrogen atmosphere, 200 mg of cyclic polyHL sample (prepared in Example 14) and 3 mol% La[N(SiMe3)2]3 were placed in a 25 mL Schlenk tube, and then 2.6 mL of toluene was added to dissolve them. The Schlenk tube was then sealed with a rubber stopper, wrapped with sealing film, removed from the glove box, and placed in a pre-set 80°C oil bath for heating and stirring for 3 hours. The solvent was then removed from the system, and 10 mg of the degradation product was taken out for further processing. 1 HL yield was analyzed by 1H NMR.

[0271] Examples 45-47

[0272] The experimental conditions were the same as in Example 44, except that the amount of reaction solvent added and / or the reaction time were changed: 2.6 mL toluene, 12 h (Example 45); 12.8 mL toluene, 3 h (Example 46); 12.8 mL toluene, 12 h (Example 47).

[0273] In summary, this invention utilizes readily available and inexpensive carbon dioxide, 1,3-butadiene, and hydrogen to synthesize a saturated lactone, and for the first time synthesizes a novel carbon dioxide-based polymer material (CO2-based polyester material) with a cyclic topology via anionic ring-opening polymerization. This material exhibits good mechanical properties, is colorless and transparent, and can be used as a pressure-sensitive adhesive. Furthermore, this cyclic polymer can be chemically recycled back to monomers under certain conditions, establishing a closed-loop circular material economy. This method avoids the environmental damage caused by white pollution and provides a novel solution for the reforming and reuse of carbon dioxide, which is of great significance for energy conservation and emission reduction.

Claims

1. A cyclic polymer, characterized in that, Its structure is shown in Formula 2. The cyclic polymer shown in Formula 2 is synthesized from the heterocyclic lactone shown in Formula 1 under the catalysis of an organic base; the organic base is selected from phosphazenes. t The reaction process of Bu-P4 is shown in reaction formula (I): ； Reaction formula (I) R1 and R2 are each independently selected from any one of hydrogen, halogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, monocyclic aromatic, substituted monocyclic aromatic, polycyclic aromatic, substituted polycyclic aromatic, polyheterocyclic aromatic, and substituted polyheterocyclic aromatic; the monocyclic aromatic is selected from phenyl, azirroaromatic, thioaromatic, and oxaaromatic; the polycyclic aromatic and polyheterocyclic aromatics refer to groups containing two or more monocyclic aromatics; R1 and R2 may be the same or different, and must coexist. X is selected from heteroatoms; n is a positive integer greater than or equal to 1; The phosphoribosil t The Bu-P4 structure is as follows: 。 2. The cyclic polymer as claimed in claim 1, characterized in that, The substituents on the alkyl, alkenyl, alkynyl, monocyclic aromatic, polycyclic aromatic, and polyheterocyclic aromatic groups are monosubstituted or polysubstituted, and are independently selected from one or more of the following groups: hydrogen, heteroatom, amino, cyano, benzyl, alkyl carbonyl, alkenyl carbonyl, cycloalkyl carbonyl, phenyl carbonyl, benzyl carbonyl, alkoxy carbonyl, ester, sulfoxide, alkenyl, alkynyl, cycloalkyl, sulfone, hydroxyl, nitro, halogen, carboxyl, alkyl, alkoxy, amino, cycloalkoxy, cycloamino, sulfinamide, sulfonamide, morpholino, and piperazine.

3. The use of the cyclic polymer as described in claim 1 or 2 in the preparation of one or more of polymer films, pressure-sensitive adhesives, tapes, and thermoplastic elastomers.

4. A polymer product, characterized in that, It is prepared from the cyclic polymer as described in claim 1 or 2; the polymer product is a polymer film or tape.

5. The cyclic polymer as described in claim 1 or 2, characterized in that, Includes one or more of the following features 1) to 7): 1) R1 is a C1-C10 alkyl group; 2) R2 is selected from C1-C10 alkyl groups; 3) X is O, S, N, or P; 4) The molar ratio of the organic base in Formula 1 is (10-500): (0.01-5); 5) The reaction is carried out under solvent-free conditions or under solvent conditions; When the method is carried out under solvent conditions, the solvent for the reaction is selected from one or more of tetrahydrofuran, benzene, toluene, xylene, dichlorobenzene, mesitylene, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydropyrrole, tetrahydropyran, hexahydropyridine, ethyl acetate, diethyl ether, dimethyl ether, methyl ethyl ether, n-hexane, cyclohexane, cyclopentane, acetonitrile, dioxane, N,N-dimethylformamide, and dimethyl sulfoxide; 6) The reaction temperature is -120~220℃; 7) The reaction time is 5 s-400 h.

6. The cyclic polymer as claimed in claim 5, characterized in that, Includes one or more of the following features: i) R1 is ethyl, R2 is ethyl, i.e. Formula 1 is HL, and the structural formula is as follows: ； ii) The molar ratio of the organic base in Formula 1 is (20-400): (0.1-4); iii) The reaction solvent is THF; iv) The reaction temperature is -80~160℃; v) The reaction time is 5 min-80 h.

7. The use of an organic base in the catalytic synthesis of a heterocyclic lactone of formula 1 into a cyclic polymer of formula 2, characterized in that, The organic base is selected from phosphazene. t Bu-P4; wherein, the heterocyclic lactone shown in Formula 1 and the cyclic polymer structure shown in Formula 2 are as follows: ； Formula 1 ； Formula 2 Wherein, R1 and R2 are independently selected from any one of hydrogen, halogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, monocyclic aromatic, substituted monocyclic aromatic, polycyclic aromatic, substituted polycyclic aromatic, polyheterocyclic aromatic, and substituted polyheterocyclic aromatic; the substituted alkyl is selected from linear alkyl, branched alkyl, and cycloalkyl; the monocyclic aromatic includes phenyl, azaaryl, thioaryl, and oxaaryl; the polycyclic aromatic and polyheterocyclic aromatic refer to groups containing two or more monocyclic aromatic groups; R1 and R2 may be the same or different, and must coexist. X is selected from heteroatoms; n is a positive integer greater than or equal to 1; The phosphoribosil t The Bu-P4 structure is as follows: 。

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