A catalyst, self-repairable degradable polyester and a preparation method thereof

Abstract

The application discloses a kind of catalyst, self-repairable degradable polyester and its preparation method, it is related to polymer synthesis technical field, the development limitation problem of self-repairable degradable polyester in prior art with cheap commercial monomer as raw material is solved.The self-repairable degradable polyester prepared in the application is polymerized from epsilon-caprolactone, cyclic anhydride and epoxide under the catalysis of catalyst and cocatalyst, wherein, the catalyst is prepared by reaction of amine-based compound, salicylaldehyde compound, manganese acetate tetrahydrate and lithium chloride, to promote the polymerization reaction of the above-mentioned monomer, so as to give the self-repairing ability of polyester.The polyester prepared in the application has adjustable components and structure, exhibits excellent mechanical properties, self-repairing ability and degradability, while using cheap commercial monomer reduces production cost and improves synthesis efficiency, meets the requirements of sustainable development.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer synthesis, in particular to a catalyst, a self-repairable degradable polyester and a preparation method thereof. BACKGROUND

[0002] In recent years, self-healing materials have gradually become a research hotspot. Self-healing materials can automatically repair their physical structure or function after mechanical damage, significantly extending the service life of the materials and reducing the frequency of material replacement, thereby saving resources and reducing costs. The concept of self-repairing originated from biological systems, for example, human skin can heal after injury through its own repair mechanism to ensure the normal function of the organism. This function has shown great potential in high-end application fields such as biomimetic materials, electronic devices, and medical materials. However, most self-healing materials rely on complex chemical reactions or external stimuli (such as heating, light, etc.) to achieve the self-repairing process, which is difficult to manufacture and apply. In contrast, materials that can self-repair at room temperature have gradually become the focus of research due to their convenience and wide applicability. However, achieving such autonomous repair often requires complex molecular design and specific chemical components, which poses new challenges to the preparation and cost control of materials.

[0003] With the increasing global environmental awareness and the rapid development of green technology, the research on degradable polymer materials has also attracted great attention. Aliphatic polyesters, as an important degradable material, are obtained through ring-opening polymerization (ROP) or ring-opening copolymerization (ROCOP) of oxacyclic fillers, have excellent biodegradability and environmental friendliness, and have been widely used in various green products. However, pure aliphatic polyesters usually exhibit low mechanical strength, heat resistance, and functionality due to their flexible and linear molecular chains.

[0004] In order to expand the application field of aliphatic polyesters, researchers have attempted to combine different monomers through copolymerization to combine self-healing and degradability, in order to prepare aliphatic polyesters with both degradability and self-repairing ability, and to endow them with high-value additional functions. However, existing self-repairing polymers rely on complex molecular design and involve multiple fragrances and highly sensitive synthesis processes, which not only increases production costs but also may limit their application range; and most self-repairing properties require external stimuli (such as heat, light, etc.) to trigger the self-repairing reaction, which means that users must have additional conditions to activate the self-repairing properties of the product, which will reduce the convenience and practicality of the material; many existing self-repairing polymers are not degradable, which leads to disposal problems after the end of the termination. Therefore, combining degradability and self-repairing to prepare polyester materials requires in-depth exploration in material design, environmental commitment, economic practicality, and other aspects to overcome current constraints and achieve a balance between the two, which is still a major challenge. SUMMARY

[0005] In order to solve the problem of the development of self-repairable and degradable polyesters using cheap commercial monomers as raw materials in the prior art, the application provides a catalyst, a self-repairable and degradable polyester and a preparation method thereof.

[0006] To achieve the above object, the application provides the following technical scheme.

[0007] The catalyst is a binuclear Schiff base manganese compound, and its structural formula is shown as (I).

[0008]

[0009] In the structural formula (I), R1 and R2 are any one of -H, a tert-butyl group, a nitro group or -Cl.

[0010] A preparation method of the catalyst, characterized in that the method comprises the following steps.

[0011] The amine-based compound shown as the structural formula (II) is condensed with the salicylaldehyde compound shown as the structural formula (III) under reflux conditions for 8-16 h to obtain a binuclear Schiff base ligand shown as the structural formula (IV); and the binuclear Schiff base ligand is refluxed with manganese acetate tetrahydrate and lithium chloride at 80 DEG C for 24-48 h to obtain the catalyst.

[0012]

[0013] In the structural formula (III) and (IV), R1 and R2 are any one of -H, a tert-butyl group, a nitro group or -Cl.

[0014] Further, the molar ratio of the amine-based compound to the salicylaldehyde compound is 1:(4-6).

[0015] Further, the molar ratio of the binuclear Schiff base ligand to manganese acetate tetrahydrate and lithium chloride is 1:2-2.5:3-4.

[0016] The self-repairable and degradable polyester is a random copolyester composed of polycaprolactone and polyacid anhydride epoxy copolymer.

[0017] The self-repairable and degradable polyester is polymerized from epsilon-caprolactone (ε-CL), cyclic acid anhydride and epoxide under the catalysis of the catalyst and the co-catalyst.

[0018] Further, the cyclic acid anhydride is any one of phthalic anhydride (PA), 4-tert-butyl-phthalic anhydride (TBA) or norbornene anhydride (CA).

[0019] Further, the epoxide is any one of propylene oxide (PO), styrene oxide (SO), phenyl glycidyl ether (BGE) or phenyl glycidyl ether (AGE);

[0020] Further, the structural formula of the above ε-caprolactone, cyclic anhydride and epoxide monomer is as follows:

[0021]

[0022] Further, the catalyst is the above catalyst;

[0023] Further, the cocatalyst is bis (triphenylphosphine) ammonium chloride;

[0024] Further, the mass ratio of the catalyst, cocatalyst, ε-caprolactone, cyclic anhydride and epoxide is 1:1:1000-6000:1000-6000:6000-10000;

[0025] Further, the poly (caprolactone) content in the random copolyester is 20%-70%.

[0026] A preparation method of a self-repairable degradable polyester, comprising the following steps:

[0027] Under the conditions of no water and no oxygen, the catalyst, cocatalyst, ε-caprolactone, cyclic anhydride and epoxide are mixed in a high-pressure reaction kettle, which is placed in an oil bath for stirring, so that the polymerization reaction is carried out under stirring to obtain a mixed solution; after the polymerization reaction is completed, the mixed solution is subjected to a settling reaction using ethanol and dilute hydrochloric acid, and after filtration, centrifugation and drying, a self-repairable degradable polyester is finally obtained;

[0028] Further, the temperature of the polymerization reaction is 100-120℃, and the time of the polymerization reaction is 24-96h;

[0029] Further, the drying temperature is 30-50℃, and the drying time is 24h-48h;

[0030] Further, the polymerization reaction is first the ring-opening alternating copolymerization reaction of the cyclic anhydride and the epoxide containing double bonds, the metal center reacts in situ with the epoxide to generate an alkoxide active species, the cyclic anhydride is first inserted into the metal alkoxide active center, and then chain growth generates an alternating copolymer of anhydride and epoxide; after the cyclic anhydride is consumed, the ε-caprolactone begins to undergo ring-opening polymerization reaction, and intermolecular transesterification reaction occurs in the ring-opening polymerization process, and the key of this reaction is that the chain structure sequence of the polymer can be disturbed by transesterification to generate a random copolymer.

[0031] Compared with the prior art, the present application solves the problem of the development limitation of self-repairable and degradable polyester using cheap commercial monomers as raw materials in the prior art. The specific beneficial effects are:

[0032] 1. The copolymerization reaction is carried out by using cheap commercial monomers (such as epsilon-caprolactone, cyclic anhydride and epoxide) in one pot in one step, which simplifies the production process, reduces the production cost and improves the synthesis efficiency;

[0033] 2. The prepared polyester has adjustable components and structure, and exhibits excellent mechanical properties, with a tensile strength of 0.15 MPa, which can adapt to different application requirements and enhance the flexibility of the material;

[0034] 3. The prepared polyester has degradable ability, reduces environmental pollution and meets the requirements of sustainable development;

[0035] 4. The prepared polyester has self-repairing ability, which is derived from the use of catalyst and cocatalyst to catalyze the polymerization of epsilon-caprolactone, cyclic anhydride and epoxide. The metal center reacts in situ with the epoxide containing double bond to generate an alkoxide active species. The cyclic anhydride is first inserted into the metal alkoxide active center, and then chain growth generates an alternating copolymer of anhydride and epoxide. When the cyclic anhydride is consumed, the epsilon-caprolactone begins to undergo ring-opening polymerization. During the ring-opening polymerization process, intermolecular transesterification occurs. The key of this reaction is that the chain structure of the polymer can be randomly disturbed by transesterification, generating a random copolymer, and then obtaining a degradable and self-repairing polyester material that can be modified and functionalized. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 MALDI-TOF-MS mass spectrum characterization diagram of catalyst;

[0037] Figure 2 NMR of polymers with different components (P1-P5) 1 H NMR;

[0038] Figure 3 C NMR of polymers with different components (P1-P5) 13 C NMR;

[0039] Figure 4 Differential scanning calorimetry diagram of polymers with different components (P1-P5);

[0040] Figure 5 Uniaxial tensile property test diagram of polymers with different components (P1-P5);

[0041] Figure 6 Self-repairing performance test diagram of polymers with different components (P1-P4). DETAILED DESCRIPTION

[0042] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as limiting the present invention.

[0043] Example 1.

[0044] 20 mmol of an amino compound and 100 mmol of 3,5-di-tert-butylsalicylaldehyde were condensed under reflux for 12 h to give 18 mmol of a biphenyl diamine di-Schiff base ligand in 90% yield. 1 mmol of the biphenyl diamine di-Schiff base ligand and 3 mmol of manganese acetate tetrahydrate were mixed in 100 mL of methanol and refluxed at 80 °C for 48 h. Then, 4 mmol of lithium chloride was added to the reaction system, and the reaction was continued under reflux at 80 °C for another 48 h to obtain the catalyst. Figure 1 The image shows the MALDI-TOF-MS mass spectrometry characterization of the catalyst.

[0045] Example 2.

[0046] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 5 mmol of PA, 30 mmol of ε-CL, and 60 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 22.5 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 95%, the polymer component PCL content was 84.2%, the PPE content was 14.3%, and the polyether content was 1.5%.

[0047] In this invention, a mixed solution was subjected to a sedimentation reaction using 500 mL of ethanol and 10 mL of dilute hydrochloric acid. After filtration, centrifugation, and vacuum drying at 50°C for 48 h, 4.2 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 133,000, and the molecular weight distribution was 1.47.

[0048] Example 3.

[0049] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 10 mmol of PA, 25 mmol of ε-CL, and 60 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 31 h. 0.1 mL of the mixture was then subjected to a 300 M [method / treatment].1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 93%, the polymer component PCL content was 70.4%, the PPE content was 27.3%, and the polyether content was 2.3%.

[0050] In this invention, a mixed solution was subjected to a sedimentation reaction using 500 mL of ethanol and 10 mL of dilute hydrochloric acid. After filtration, centrifugation, and vacuum drying at 50°C for 48 h, 4.5 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 160,000, and the molecular weight distribution was 1.44.

[0051] Example 4.

[0052] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 10 mmol of PA, 25 mmol of ε-CL, and 60 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 60 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 99%, the polymer component PCL content was 66.2%, the PPE content was 27.8%, and the polyether content was 6.0%.

[0053] In this invention, a mixture of 500 mL ethanol and 10 mL dilute hydrochloric acid was subjected to a sedimentation reaction. After filtration, centrifugation, and vacuum drying at 50 °C for 48 h, 4.4 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 102,000, and the molecular weight distribution was 1.43.

[0054] Example 5.

[0055] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 15 mmol of PA, 20 mmol of ε-CL, and 60 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 64 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 96%, the polymer component PCL content was 54.3%, the PPE content was 40.7%, and the polyether content was 5.0%.

[0056] In this invention, a mixed solution was subjected to a sedimentation reaction using 1000 mL of ethanol and 20 mL of dilute hydrochloric acid. After filtration, centrifugation, and vacuum drying at 50°C for 48 h, 5.0 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 78,000, and the molecular weight distribution was 1.53.

[0057] Example 6.

[0058] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 20 mmol of PA, 15 mmol of ε-CL, and 60 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 70 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 97%, the polymer component PCL content was 39.7%, the PPE content was 51.9%, and the polyether content was 8.4%.

[0059] In this invention, a mixed solution was subjected to a sedimentation reaction using 1000 mL of ethanol and 20 mL of dilute hydrochloric acid. After filtration, centrifugation, and vacuum drying at 50°C for 48 h, 5.4 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 73,000, and the molecular weight distribution was 1.51.

[0060] Example 7.

[0061] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 25 mmol of PA, 10 mmol of ε-CL, and 60 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 60 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 91%, the polymer component PCL content was 27.7%, the PPE content was 65.8%, and the polyether content was 6.5%.

[0062] In this invention, a mixture of 1000 mL ethanol and 20 mL dilute hydrochloric acid was subjected to a sedimentation reaction. After filtration, centrifugation, and vacuum drying at 50 °C for 48 h, 6.1 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 61,000, and the molecular weight distribution was 1.54.

[0063] Example 8.

[0064] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 10 mmol of PA, 25 mmol of ε-CL, and 30 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 35 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 95%, the polymer component PCL content was 70.8%, the PPE content was 27.0%, and the polyether content was 2.2%.

[0065] In this invention, a mixture of 500 mL ethanol and 10 mL dilute hydrochloric acid was subjected to a sedimentation reaction. After filtration, centrifugation, and vacuum drying at 50 °C for 48 h, 4.5 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography. The number average molecular weight of the copolymer was found to be 162,000, and the molecular weight distribution was 1.41. The polymer was labeled as P1.

[0066] Example 9.

[0067] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 15 mmol of PA, 20 mmol of ε-CL, and 30 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 66 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 96%, the polymer component PCL content was 57.6%, the PPE content was 40.0%, and the polyether content was 2.4%.

[0068] In this invention, a mixed solution was subjected to a sedimentation reaction using 1000 mL of ethanol and 20 mL of dilute hydrochloric acid. After filtration, centrifugation, and vacuum drying at 50°C for 48 h, 5.0 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 123,000, with a molecular weight distribution of 1.54. This polymer was labeled as P2.

[0069] Example 10.

[0070] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 17.5 mmol of PA, 17.5 mmol of ε-CL, and 30 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 88 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 98%, the polymer component PCL content was 49.0%, the PPE content was 48.1%, and the polyether content was 2.9%.

[0071] In this invention, a mixture of 1000 mL ethanol and 20 mL dilute hydrochloric acid was subjected to a sedimentation reaction. After filtration, centrifugation, and vacuum drying at 50 °C for 48 h, 5.0 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography. The number average molecular weight of the copolymer was found to be 124,000, and the molecular weight distribution was 1.56. The polymer was labeled as P3.

[0072] Example 11.

[0073] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 20 mmol of PA, 15 mmol of ε-CL, and 30 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 65 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 94%, the polymer component PCL content was 41.1%, the PPE content was 58.6%, and the polyether content was 0.3%.

[0074] In this invention, a mixture of 1000 mL ethanol and 20 mL dilute hydrochloric acid was subjected to a sedimentation reaction. After filtration, centrifugation, and vacuum drying at 50 °C for 48 h, 5.0 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography. The number average molecular weight of the copolymer was found to be 125,000, and the molecular weight distribution was 1.60. The polymer was labeled as P4.

[0075] Example 12.

[0076] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 25 mmol of PA, 10 mmol of ε-CL, and 30 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 90 h. Approximately 0.1 mL of the mixed solution was then subjected to a 300 M reaction. 1 The samples were characterized by H NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 93%, the polymer component PCL content was 21.9%, the PPE content was 76.9%, and the polyether content was 1.5%.

[0077] In this invention, a mixture of 1000 mL ethanol and 20 mL dilute hydrochloric acid was subjected to a sedimentation reaction. After filtration, centrifugation, and vacuum drying at 50 °C for 48 h, 5.0 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography. The number average molecular weight of the copolymer was found to be 147,000, and the molecular weight distribution was 1.48. The polymer was labeled as P5.

[0078] Figure 2 The 1H NMR spectra of the polymers (P1-P5) of different components in Examples 8-12 1 The H NMR spectrum shows that the signal intensity of the anhydride epoxy copolymer in the polymer increases with the increase of the amount of anhydride added, while the signal proportion of the linking unit decreases, indicating that the degree of transesterification is reduced; the polyether content is controlled within 3%. Figure 3 Carbon NMR spectra of different component polymers (P1-P5) in Examples 8-12 13 C NMR shows that the signal intensity of the anhydride epoxy copolymer in the polymer increases with the increase of the amount of anhydride added, while the signal proportion of the linking unit decreases, indicating that the degree of transesterification is reduced. Figure 4 Differential scanning calorimetry (DSC) images of the different component polymers (P1-P5) obtained in Examples 8-12 show that each copolymer has no melting point, only a glass transition temperature, which increases with the increase of anhydride addition. Figure 5 The figures show the uniaxial tensile properties of the polymers (P1-P5) with different components obtained in Examples 8-12. It can be seen that the tensile properties of the copolymers increase with the increase of the content of acid anhydride and epoxy copolymer. Among them, P4 is an elastomer, and P5, which has the highest content of acid anhydride and epoxy copolymer, is a brittle plastic.

[0079] Example 13.

[0080] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 25 mmol of PA, 10 mmol of ε-CL, and 30 mmol of SO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 48 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% NMR, and the results showed that the PA conversion rate was 100%, the ε-CL conversion rate was 93%, the polymer component PCL content was 22.6%, the PSE content was 77.4%, and the polyether content was 0%.

[0081] In this invention, a mixed solution was subjected to a sedimentation reaction using 1000 mL of ethanol and 20 mL of dilute hydrochloric acid. After filtration, centrifugation, and vacuum drying at 50°C for 48 h, 4.0 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 17,000, and the molecular weight distribution was 1.88.

[0082] Example 14.

[0083] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 25 mmol of TBA, 10 mmol of ε-CL, and 30 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 70 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% H NMR. The results showed that the TBA conversion rate was 100%, the ε-CL conversion rate was 90%, the polymer component PCL content was 22.5%, the TBPE content was 75.1%, and the polyether content was 2.4%.

[0084] In this invention, a mixed solution was subjected to a sedimentation reaction using 1000 mL of ethanol and 20 mL of dilute hydrochloric acid. After filtration, centrifugation, and vacuum drying at 50°C for 48 h, 5.3 g of polymer was finally obtained. Styrene was used as a standard. The polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 97,000, and the molecular weight distribution was 1.50.

[0085] Example 15.

[0086] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of co-catalyst, 25 mmol of CA, 10 mmol of ε-CL, and 30 mmol of PO were mixed in a 25 mL high-pressure reactor and stirred in a 100 °C oil bath for 75 h. 0.1 mL of the mixture was then subjected to a 300 M... 1The samples were characterized by 100% TBA conversion and 92% ε-CL conversion. The polymer components PCL content was 24.0%, TBPE content was 73.1%, and polyether content was 2.9%.

[0087] In this invention, a mixture of 1000 mL ethanol and 20 mL dilute hydrochloric acid was subjected to a sedimentation reaction. After filtration, centrifugation, and vacuum drying at 50 °C for 48 h, 4.8 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 107,000, and the molecular weight distribution was 1.52.

[0088] Example 16.

[0089] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 10 mmol of PA, 25 mmol of ε-CL, and 30 mmol of BGE were mixed in a 25 mL high-pressure reactor and stirred in a 120 °C oil bath for 48 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% TBA conversion and 92% ε-CL conversion. The polymer components PCL content was 70.4%, PBE content was 26.5%, and polyether content was 3.1%.

[0090] In this invention, a mixed solution was subjected to a sedimentation reaction using 1000 mL of ethanol and 20 mL of dilute hydrochloric acid. After filtration, centrifugation, and vacuum drying at 50°C for 48 h, 5.5 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 87,000, and the molecular weight distribution was 1.47.

[0091] Example 17.

[0092] Under anhydrous and oxygen-free conditions, 0.005 mmol of the catalyst prepared in Example 1, 0.005 mmol of the co-catalyst, 10 mmol of PA, 25 mmol of ε-CL, and 30 mmol of AGE were mixed in a 25 mL high-pressure reactor and stirred in a 120 °C oil bath for 48 h. 0.1 mL of the mixture was then subjected to a 300 M... 1 The samples were characterized by 100% TBA conversion and 97% ε-CL conversion. The polymer components PCL content was 69.4%, PAE content was 27.0%, and polyether content was 3.6%.

[0093] In this invention, a mixed solution was subjected to a sedimentation reaction using 1000 mL of ethanol and 20 mL of dilute hydrochloric acid. After filtration, centrifugation, and vacuum drying at 50°C for 48 h, 4.5 g of polymer was finally obtained. Using polystyrene as a standard, the polymer obtained in this example was analyzed by size exclusion chromatography, and the number average molecular weight of the copolymer was found to be 117,000, and the molecular weight distribution was 1.57.

[0094] Self-healing performance test:

[0095] Taking the polymer in Example 8 as an example, the self-healing ability of the polymer was characterized. The dried polymer was hot-pressed to obtain a polymer film with a thickness of 2–4 mm. The polymer film was then cut into dumbbell-shaped samples according to international standard GB / T1040. Uniaxial tensile tests were performed on the samples according to international standard ISO 527 (the clamp movement speed for all samples was 10 mm / min). -1 The initial tensile strength of the polymer sample was 0.15 MPa. The sample was then cut shorter, and the two ends were aligned to ensure complete contact. After being placed at room temperature for 2 hours, a uniaxial tensile test was performed on the repaired sample according to international standard ISO 527, and the repaired tensile strength was found to be 0.10 MPa. Figure 6 The graphs show the self-healing performance of the polymers (P1-P4) with different components obtained in Examples 8-11. It can be seen that the self-healing efficiency of the copolymer decreases with the increase of the content of acid anhydride and epoxy copolymer, and P1 has the best repair effect.

[0096] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A self-healing, biodegradable polyester, characterized in that, It is a random copolyester composed of polycaprolactone and polyanhydride epoxy copolymer; The self-healing biodegradable polyester is polymerized from ε-caprolactone, cyclic anhydride, and epoxide under the catalysis of a catalyst and a co-catalyst. The cyclic anhydride is any one of phthalic anhydride, 4-tert-butyl-phthalic anhydride or norbornene anhydride; The epoxide is any one of propylene oxide, styrene oxide, phenyl glycidyl ether, or allyl glycidyl ether. The catalyst has the following structural formula: (I) （I）； In the structural formula (I), the R1 and R2 groups are any one of -H, tert-butyl, nitro or -Cl; The co-catalyst is bis(triphenylphosphine)ammonium chloride.

2. The self-healing biodegradable polyester according to claim 1, characterized in that, The molar ratio of the catalyst, co-catalyst, ε-caprolactone, cyclic anhydride and epoxide is 1:1:1000~6000:1000~6000:6000~10000.

3. The self-healing biodegradable polyester according to claim 1, characterized in that, The random copolyester contains 20% to 70% polycaprolactone.

4. The self-healing biodegradable polyester according to claim 1, characterized in that, The preparation method of the catalyst includes the following steps: An amino compound with the structure shown in (II) and a salicylaldehyde compound with the structure shown in (Ш) are condensed under reflux for 8-16 h to obtain a binuclear Schiff base ligand with the structure shown in (IV); the binuclear Schiff base ligand is then refluxed with manganese acetate tetrahydrate and lithium chloride at 80 °C for 24-48 h to obtain the catalyst as described in claim 1. (II); (W); (IV); In the structural formulas (Ш) and (IV), the R1 and R2 groups are any one of -H, tert-butyl, nitro or -Cl.

5. The self-healing biodegradable polyester according to claim 4, characterized in that, The molar ratio of the amino compound to the salicylaldehyde compound is 1:(4~6).

6. The self-healing biodegradable polyester according to claim 4, characterized in that, The molar ratio of the binuclear Schiff base ligand to manganese acetate tetrahydrate and lithium chloride is 1:2~2.5:3~4.

7. A method for preparing a self-healing biodegradable polyester as described in any one of claims 1-6, characterized in that, Includes the following steps: Under anhydrous and oxygen-free conditions, the catalyst, co-catalyst, ε-caprolactone, cyclic anhydride, and epoxide are mixed in a high-pressure reactor and placed in an oil bath for stirring to carry out a polymerization reaction and obtain a mixed solution. After the polymerization reaction is completed, the mixed solution is subjected to a sedimentation reaction using ethanol and dilute hydrochloric acid. After filtration, centrifugation, and drying, a self-healing biodegradable polyester is finally obtained.

8. The method for preparing the self-healing biodegradable polyester according to claim 7, characterized in that, The polymerization reaction is carried out at a temperature of 100~120℃ for 24~96 h.

9. The method for preparing the self-healing biodegradable polyester according to claim 7, characterized in that, The drying temperature is 30~50℃, and the drying time is 24 h~48 h.

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