Toughening modified polyglycolic acid material and preparation method thereof

Abstract

The invention provides a toughened modified polyglycolic acid material and a preparation method thereof. The toughening modified polyglycolic acid material provided by the invention comprises a reaction product of a modified polyglycolic acid material and a sulfur-containing compound, and the modified polyglycolic acid material is a polymerization product of glycolide, other cyclic lactones and unsaturated micromolecular polyol. By adopting a method of block copolymerization of polyglycolic acid and other cyclic lactones, the regularity of a molecular chain structure is changed, the crystallinity of the polyglycolic acid is destroyed, and the structural regularity of a molecular chain of the polyglycolic acid is disrupted, so that the toughness of the polyglycolic acid is improved, the impact strength of the polyglycolic acid is improved, and the mechanical property of the polyglycolic acid is improved; the application range of the polyglycolic acid material is expanded.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a toughened modified polyglycolic acid material and its preparation method. Background Technology

[0002] With the improvement of living standards and continuous economic development, the public's demand for plastic products is increasing. However, along with the development of plastic products, problems have also emerged, among which environmental pollution and energy crisis are the most prominent. Biodegradable materials have reduced the impact of white pollution on the environment and are currently widely used in food, automobiles, packaging, medical and other fields. Biodegradable materials refer to materials that are first decomposed into small molecule intermediates under the action of bacteria, molds and enzymes, and then decomposed into carbon dioxide and water. Ideal biodegradable materials not only meet certain performance requirements, but also do not produce harmful decomposition products. Most non-degradable plastics are derived from petroleum-based polymers. In my country, where there is "abundant coal and scarce oil," a series of coal chemical products have emerged to reduce over-reliance on petroleum, including coal-derived methyl glycolate (MG) and its polymer product—polyglycolic acid (PGA). PGA can effectively replace petroleum-based polymers. Polyglycolic acid (PGA) is the simplest polymer in structure among aliphatic thermoplastic polyesters. Its monomer, glycolic acid (GA), has a single carbon atom linked to both a hydroxyl and a carboxyl group on its main chain, without any other side groups. This gives its macromolecules high regularity, resulting in advantages such as high crystallinity, high strength, high heat distortion temperature, excellent barrier properties, and good biocompatibility and biodegradability. However, PGA also has significant drawbacks, such as poor processing thermal stability, low melt strength, and high brittleness. Its high brittleness, in particular, limits its application range, significantly restricting its use in film products, packaging materials, tableware, and injection molded parts. Therefore, toughening modification of PGA is necessary.

[0003] PGA, as an emerging biodegradable material, possesses excellent biocompatibility and good mechanical properties. However, its poor elasticity, low impact strength, and susceptibility to bending deformation significantly limit its applications. Therefore, toughening modification is necessary to improve the overall performance of PGA. PGA modification mainly falls into two categories: First, by using methods such as compounding, plasticizing, or blending, certain additives, functional groups, or other polymeric materials are added to the macroscopic composition of PGA, which can effectively improve its application performance. Second, other monomers are introduced through copolymerization to change the microscopic molecular structure of PGA, or surface modification or crosslinking methods are used to change its molecular chain structure, thereby specifically and thoroughly modifying its matrix. Both of these methods are the main approaches to toughening modification of polymeric materials. Summary of the Invention

[0004] This invention proposes using glycolide and other cyclic lactones as monomers to introduce unsaturated small-molecule polyols into block copolymers, introducing double bonds into the block copolymers. Subsequently, the double bonds in the block copolymers are vulcanized to form a cross-linked network, achieving a good toughening effect on polyglycolic acid (PGA). The introduction of flexible molecular chains into the main chain of PGA disrupts the regular arrangement of the PGA molecular chains, reducing their regularity and thus improving the toughness of the PGA material.

[0005] One objective of this invention is to provide a toughened modified polyglycolic acid material, comprising a reaction product of a polyglycolic acid block copolymer and a sulfur-containing compound, wherein the polyglycolic acid block copolymer is a polymerization product of glycolide, other cyclic lactones, and unsaturated small molecule polyols.

[0006] In the toughened modified polyglycolic acid material provided by this invention:

[0007] The other cyclic lactones mentioned are selected from at least one of C3-C12 cyclic lactones, preferably from at least one of lactide, caprolactone, butyrolactone, heptanolactone, and octylolactone;

[0008] The unsaturated small molecule polyol is selected from at least one of α-allylglycerol ether, trimethylolpropane monoallyl ether, and 1,4-butenediol;

[0009] The sulfur-containing compound is selected from at least one of sulfur, dicumyl peroxide, benzoyl peroxide, and ethylene dithiol.

[0010] The second objective of this invention is to provide a method for preparing the above-mentioned toughened modified polyglycolic acid material, comprising: subjecting a polyglycolic acid block copolymer to a sulfur-containing compound through a sulfurization reaction to obtain the toughened modified polyglycolic acid material.

[0011] Specifically, the preparation method of the toughened modified polyglycolic acid material includes the following steps:

[0012] (1) Polymerize components including glycolide, other cyclic lactones, and unsaturated small molecule polyols under the action of a catalyst to obtain polyglycolic acid block copolymer;

[0013] (2) The polyglycolic acid block copolymer obtained in step (1) and the sulfur-containing compound are subjected to a sulfurization reaction to obtain the toughened modified polyglycolic acid material.

[0014] In the above-mentioned method for preparing toughened modified polyglycolic acid materials:

[0015] The other cyclic lactones mentioned are selected from at least one of C3-C12 cyclic lactones, preferably from at least one of lactide (e.g., L-lactide, D-lactide, DL-lactide), caprolactone, butyrolactone, heptanolide (e.g., γ-heptanolide, δ-heptanolide), and octanolide (e.g., δ-octanolide).

[0016] The unsaturated small molecule polyol is selected from at least one of α-allylglycerol ether, trimethylolpropane monoallyl ether, and 1,4-butenediol;

[0017] The catalyst is selected from at least one of 4-diaminopyridine, phosphonium, thiourea, 1,5,7-triazidobicyclo(4,4,0)dec-5-ene, ferric chloride, aluminum chloride, sodium alkoxide, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, di(dodecyl sulfide)dibutyltin, stannous tetrachloride, stannous chloride, stannous acetate, and stannous oxide, preferably from at least one of stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, di(dodecyl sulfide)dibutyltin, stannous tetrachloride, and stannous chloride;

[0018] The sulfur-containing compound is selected from at least one of sulfur, dicumyl peroxide, benzoyl peroxide, and ethylene dithiol.

[0019] In the above-mentioned method for preparing toughened modified polyglycolic acid materials:

[0020] Based on a total weight of 100 parts by weight of the glycolide and other cyclic lactones, the amount of glycolide is 30-90 parts, the amount of other cyclic lactones is 10-70 parts, and the amount of unsaturated small molecule polyol is 0.5-8 parts; preferably, based on a total weight of 100 parts by weight of the glycolide and other cyclic lactones, the amount of glycolide is 50-90 parts, the amount of other cyclic lactones is 10-50 parts, and the amount of unsaturated small molecule polyol is 1-5 parts.

[0021] The amount of catalyst can be adjusted within a wide range. For example, based on 100 parts by weight of the total weight of the glycolide and other cyclic lactones, the amount of catalyst is 0.1 to 6 parts, preferably 1 to 3 parts.

[0022] The amount of the sulfur-containing compound can be adjusted within a wide range. For example, based on 100 parts by weight of the total weight of the glycolide and other cyclic lactones, the amount of the sulfur-containing compound is 0.5 to 6 parts, preferably 2 to 4 parts.

[0023] In step (1) of the above-mentioned method for preparing toughened modified polyglycolic acid material, the components including glycolide, other cyclic lactones, and unsaturated small molecule polyols need to be heated to form a homogeneous phase before the polymerization reaction. The heating conditions are: a heating temperature of 50–150°C and a heating time of 0.5–1.5 h; preferably, the heating conditions are: a heating temperature of 80–100°C and a heating time of 0.8–1.2 h.

[0024] In the above-mentioned method for preparing toughened modified polyglycolic acid materials:

[0025] The polymerization reaction conditions in step (1) are 90-100℃ for 40-60 min;

[0026] The polymerization reaction is followed by a drying step, preferably at a temperature of 50–60°C.

[0027] The conditions for the sulfidation reaction in step (2) are 160-180℃ for 15-45 minutes.

[0028] Polyglycolic acid (PGA) itself has a regular molecular chain and high crystallinity. This invention, through copolymerization of glycolide and other cyclic lactones, effectively improves the thermal stability and controllable degradation of PGA copolymers, disrupts the regularity of the PGA molecular chain structure, and reduces its crystallinity, thereby improving its impact strength. Furthermore, the addition of unsaturated small-molecule polyols introduces double bonds into the copolymer's molecular chain, followed by vulcanization treatment with sulfur-containing compounds, forming a dense cross-linked network within the copolymer. This further enhances the toughness and mechanical properties of PGA materials, expanding their application range. Attached Figure Description

[0029] Figure 1 The results are DSC test results for the toughened modified polyglycolic acid material obtained in Example 3. Figure 1 In the diagram, a represents toughened modified polyglycolic acid material with a melting point of 167℃; b represents polycaprolactone with a melting point of 42℃; and c represents polyglycolic acid with a melting point of 224℃.

[0030] Figure 2 The thermal degradation curve of the toughened modified polyglycolic acid material obtained in Example 3 is shown. Figure 2 In the diagram, a represents polyglycolic acid, b represents toughened modified polyglycolic acid material, and c represents polyglycolic acid. Detailed Implementation

[0031] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0032] This invention improves the toughness of polyglycolic acid by introducing double bonds into the molecular chain of a polyglycolic acid block copolymer and then forming a dense cross-linked network through the vulcanization of these double bonds. Furthermore, by adjusting the ratio of comonomers and unsaturated small-molecule polyols, suitable polyglycolic acid copolymers can be prepared to enhance the toughness of polyglycolic acid materials.

[0033] According to a preferred embodiment of the present invention, the preparation method of the toughened modified polyglycolic acid material specifically includes the following steps:

[0034] Step 1: Synthesize glycolide, specifically as follows:

[0035] A certain amount of glycolic acid is added to a three-necked flask equipped with a distillation apparatus. The reaction temperature is raised from room temperature to 100-140℃, and then butyllithium catalyst is added. The temperature is further increased to 160-200℃, water is used as the condensing medium, and the vacuum degree in the reaction vessel is increased to 10-20 mmHg and maintained for a certain period of time to remove the water generated in the reaction under vacuum. The temperature is further increased to 250-270℃, and the vacuum degree in the vessel is maintained at about 1-4 mmHg. Air is used instead of water as the condensing medium. The crude product is a pale yellow waxy solid. It is dissolved in ethyl acetate and recrystallized, then decolorized with activated carbon to obtain a pure product. Pure glycolide is a colorless crystal, which is stored under vacuum and dried with phosphorus pentoxide. To purify glycolide, a small amount of ethyl acetate solvent is added to dissolve the glycolide in the flask to obtain a hot saturated solution. If insoluble impurities are present, the solution is filtered while hot. Decolorization is performed with activated carbon, using the minimum amount added in several portions, with constant stirring, and then filtered. Finally, let it stand and wait for crystallization. Once the crystals have completely precipitated, filter it under reduced pressure using a funnel.

[0036] Step 2: Unsaturated small molecule polyols initiate the copolymerization of glycolide and caprolactone, specifically as follows:

[0037] Other cyclic lactones need to be distilled under reduced pressure under nitrogen protection before use, collecting the fraction at 80-90℃ and 150-200Pa. Glycolide, other cyclic lactones, and unsaturated small-molecule polyols are placed in a silanized small polymerization tube, with 30-90 parts glycolide, 10-70 parts other cyclic lactones, and 0.5-8 parts unsaturated small-molecule polyols. A catalyst is then added, and the mixture is heated at 50-150℃ for 0.5-1.5 hours, followed by vacuum sealing to completely immerse the tube in oil and prevent evaporation of cooled portions. Bulk polymerization is then carried out at 90-100℃ for a certain time. The mixture is then dried in a vacuum oven at 50-60℃ to finally prepare a random block copolymer.

[0038] The cyclic lactones used in this invention include, but are not limited to, one or more of the following: glycolide, L-lactide, D-lactide, DL-lactide, caprolactone, butyrolactone, γ-heptylactone, δ-heptylactone, and δ-octylactone.

[0039] The unsaturated small molecule polyols used in this invention include, but are not limited to, one or more of α-allyl glycerol ether, trimethylolpropane monoallyl ether, and 1,4-butenediol.

[0040] The catalysts used in this invention include, but are not limited to, one or more of the following: 4-diaminopyridine, phosphonium, thiourea, 1,5,7-triazidobicyclo(4,4,0)dec-5-ene, ferric chloride, aluminum chloride, sodium alkoxide, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, di(dodecyl sulfide)dibutyltin, stannous tetrachloride, stannous chloride, stannous acetate, and tin oxide.

[0041] Step 3, vulcanization of the random block copolymer, specifically:

[0042] A sulfur-containing compound was added to the prepared random block copolymer, with 0.5-6 parts of the sulfur-containing compound added per 100 parts of the block copolymer. The block copolymer with the added sulfur-containing compound was then vulcanized on a flat vulcanizing machine at a vulcanization temperature of 160-180℃ for 15-45 minutes. The toughened and modified polyglycolic acid random block copolymer was finally obtained.

[0043] The testing instruments and conditions used in this embodiment are as follows:

[0044] DSC test: Differential scanning calorimetry was performed using the STARe system from Mettler Toledo, Switzerland. The sample was heated from 25°C to 250°C, held at 250°C for 3 min, cooled to -70°C, held for 3 min, and then heated back to 250°C. The heating and cooling rates were set to 10°C / min during the test, which was conducted in an N2 atmosphere.

[0045] TGA testing: A thermogravimetric analyzer from Switzerland was used. The experimental parameters were set as follows: heating rate of 10℃ / min, N2 atmosphere, heating from room temperature to 800℃.

[0046] Dynamic mechanical properties test: Dynamic mechanical properties were tested using DMA Q800 (TAInstruments) in single cantilever mode, within the range of -100℃ to 250℃. The specific test conditions were: strain 1%, frequency 1Hz, heating rate 3℃ / min, and N2 atmosphere.

[0047] Mechanical property testing: Pure PGA, PCL, and PGA / PCL copolymers were injection molded into tensile test specimens according to ASTM D638, Type IV standard. The specimens were then subjected to tensile testing at 20 mm / min on a tensile testing machine (SANS CMT 4104, China) at 25°C. Each sample required at least 5 tensile tests. The blends were injection molded into impact test specimens according to GB / T1843-2008, 80*10*4mm, Type A standard. The impact test specimens were then tested at 25°C using a cantilever beam impact testing machine (TF-XBL). Each sample required at least 5 impact tests.

[0048] SEM testing: Samples of pure PGA, PCL, and PGA / PCL copolymers were frozen in liquid nitrogen for 15 min to quench them, etched with N,N-dimethylformamide (DMF) for 5 days, and the cross-sectional morphology of the gold-sprayed samples was measured using a scanning electron microscope (SEM, Hitachi S4800, Japan) with an accelerating voltage of 5 kV.

[0049] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0050] The glycolide used in the examples and comparative examples was purchased from Shanghai Special Reagent Development Center, caprolactone was purchased from Aldrich Chemical Company, USA, and stannous octoate was purchased from Sigma Chemical Company, USA. All products were dried in an oven at 60°C for 12 hours before use.

[0051] Example 1

[0052] The monomer ratio of glycolide to caprolactone was 90 / 10. The two monomers were placed in a silanized small polymerization tube, and 5 parts of unsaturated small-molecule polyol trimethylolpropane monoallyl ether and 2 parts of stannous octoate were added as a catalyst. The mixture was heated at 120℃ for 1 hour to obtain a homogeneous material. After vacuum sealing, the mixture was completely immersed in oil and bulk polymerized at 100℃ for 1 hour. The reaction product was dried in a vacuum oven at 60℃ to obtain the desired copolymer. The copolymer was mixed evenly with 3 parts of sulfur on a two-roll mill and vulcanized for 30 minutes on a flat vulcanizing mill at 170℃ and 30MPa to prepare the toughened modified polyglycolic acid material P1.

[0053] Example 2

[0054] The monomer ratio of glycolide to caprolactone was 80 / 20. The two monomers were placed in a silanized small polymerization tube, and 5 parts of unsaturated small-molecule polyol trimethylolpropane monoallyl ether and 2 parts of stannous octoate were added as a catalyst. The mixture was heated at 120℃ for 1 hour to obtain a homogeneous material. After vacuum sealing, the mixture was completely immersed in oil and bulk polymerized at 100℃ for 1 hour. The reaction product was dried in a vacuum oven at 60℃ to obtain the desired copolymer. The copolymer was mixed evenly with 3 parts of sulfur on a two-roll mill and vulcanized for 30 minutes on a flat vulcanizing machine at 170℃ and 30MPa to prepare the toughened modified polyglycolic acid material P2.

[0055] Example 3

[0056] The monomer ratio of glycolide to caprolactone was 70 / 30. The two monomers were placed in a silanized small polymerization tube, and 5 parts of unsaturated small-molecule polyol trimethylolpropane monoallyl ether and 2 parts of stannous octoate were added as a catalyst. The mixture was heated at 120℃ for 1 hour to obtain a homogeneous material. After vacuum sealing, the mixture was completely immersed in oil and bulk polymerized at 100℃ for 1 hour. The reaction product was dried in a vacuum oven at 60℃ to obtain the desired copolymer. The copolymer was mixed evenly with 3 parts of sulfur on a two-roll mill and vulcanized for 30 minutes on a flat vulcanizing machine at 170℃ and 30MPa to prepare the toughened modified polyglycolic acid material P3.

[0057] Example 4

[0058] The monomers of glycolide and caprolactone were mixed in a 60 / 40 ratio. The glycolide and caprolactone monomers were placed in a silanized small polymerization tube, and 5 parts of unsaturated small-molecule polyol trimethylolpropane monoallyl ether and 2 parts of stannous octoate were added as a catalyst. The mixture was heated at 120°C for 1 hour to obtain a homogeneous material. After vacuum sealing, the mixture was completely immersed in oil and bulk polymerized at 100°C for 1 hour. The reaction product was dried in a vacuum oven at 60°C to obtain the desired copolymer. The copolymer was mixed evenly with 3 parts of sulfur on a two-roll mill and vulcanized for 30 minutes on a flat vulcanizing mill at 170°C and 30 MPa to prepare the toughened modified polyglycolic acid material P4.

[0059] Example 5

[0060] The monomers of glycolide and caprolactone were mixed in a 50 / 50 ratio. The glycolide and caprolactone monomers were placed in a silanized small polymerization tube, and 5 parts of unsaturated small-molecule polyol trimethylolpropane monoallyl ether and 2 parts of stannous octoate were added as a catalyst. The mixture was heated at 120℃ for 1 hour to obtain a homogeneous material. After vacuum sealing, the mixture was completely immersed in oil and bulk polymerized at 100℃ for 1 hour. The reaction product was dried in a vacuum oven at 60℃ to obtain the desired copolymer. The copolymer was mixed evenly with 3 parts of sulfur on a two-roll mill and vulcanized for 30 minutes on a flat vulcanizing machine at 170℃ and 30MPa to prepare the toughened modified polyglycolic acid material P5.

[0061] Example 6

[0062] The monomer ratio of glycolide to caprolactone was 80 / 20. The two monomers were placed in a silanized small polymerization tube, and 3 parts of unsaturated small-molecule polyol trimethylolpropane monoallyl ether and 2 parts of stannous octoate were added as a catalyst. The mixture was heated at 120℃ for 1 hour to obtain a homogeneous material. After vacuum sealing, the mixture was completely immersed in oil and bulk polymerized at 100℃ for 1 hour. The reaction product was dried in a vacuum oven at 60℃ to obtain the desired copolymer. The copolymer was mixed evenly with 3 parts of sulfur on a two-roll mill and vulcanized for 30 minutes on a flat vulcanizing mill at 170℃ and 30 MPa to prepare the toughened modified polyglycolic acid material P6.

[0063] Example 7

[0064] Preparation of glycolide:

[0065] A certain amount of glycolic acid was added to a three-necked flask equipped with a distillation apparatus, and the reaction temperature was raised from room temperature to 120°C. Then, butyllithium catalyst was added. The temperature was further increased to 180°C, with water used as the condensing medium, and the vacuum in the reaction vessel was increased to 15 mmHg and maintained for a certain period of time to remove the water generated in the reaction. The temperature was further increased to 260°C, with the vacuum in the vessel maintained at approximately 3 mmHg, and air was used instead of water as the condensing medium. The crude product was a pale yellow waxy solid. It was dissolved in ethyl acetate and recrystallized, then decolorized with activated carbon to obtain a pure product for later use.

[0066] Preparation of toughened modified polyglycolic acid materials:

[0067] Laboratory-prepared glycolide monomers were used, with a glycolide / caprolactone monomer ratio of 80 / 20. The glycolide and caprolactone monomers were placed in a silanized small polymerization tube, and 5 parts of unsaturated small-molecule polyol trimethylolpropane monoallyl ether and 2 parts of stannous octoate were added as a catalyst. The mixture was heated at 120℃ for 1 hour to obtain a homogeneous material. After vacuum sealing, the mixture was completely immersed in oil and bulk polymerized at 100℃ for 1 hour. The reaction product was dried in a vacuum oven at 60℃ to obtain the desired copolymer. The copolymer was mixed evenly with 3 parts of sulfur on a two-roll mill and vulcanized for 30 minutes on a flat vulcanizing machine at 170℃ and 30 MPa to prepare the toughened modified polyglycolic acid material P7.

[0068] Comparative Example 1

[0069] Pure PGA (purchased from Shanghai Pujing Chemical Co., Ltd.) was directly added to the injection molding machine, with the barrel temperature at 230℃, the mold temperature at 70℃, and the holding time at 8 seconds, to injection mold the specimens required for the experiment.

[0070] Table 1

[0071]

[0072] The tensile strength of pure PGA is around 140 MPa, but its elongation at break is only 5.7%, and its impact strength is only 2.9 kJ / m. 2 PGA is a typical brittle material. Block copolymers were prepared by block copolymerization of glycolide (PGA) and caprolactone (PCL), a monomer of the flexible material, to improve the toughness of PGA. A copolymer with a monomer composition of 90% glycolide and 10% caprolactone achieved a tensile strength of 120.3 MPa, showing a slight decrease in tensile strength. The elongation at break was 34.6%, a significant improvement of 6.1 times compared to pure PGA. The impact strength was 3.4 kJ / m. 2The improvement is not very significant. The monomer composition is a copolymer of 80% glycolide and 20% caprolactone, with a tensile strength of 109.6 MPa and an elongation at break of 49.7%, representing an 8.7-fold increase compared to pure PGA. The impact strength is 6.2 kJ / m². 2 The performance has been improved to some extent. The monomer composition is a copolymer of 70% glycolide and 30% caprolactone, with a tensile strength of 95.5 MPa and an elongation at break of 110.2%, representing a 19.3-fold increase compared to pure PGA. The impact strength is 16.2 kJ / m². 2 The tensile strength was significantly improved. However, with increasing polycaprolactone (PCL) content in the copolymer, the tensile strength gradually decreased, and the elongation at break and impact strength also decreased. The highest impact strength, at 16.2 kJ / m, was achieved when the PCL content was 30%. 2 .

[0073] As the PCL content in the copolymer increases, the tensile strength gradually decreases, while the elongation at break and impact strength both initially increase and then decrease, reaching their maximum values ​​when the PCL content is 30%. This is because caprolactone itself is a flexible molecule. After copolymerization with glycolide, flexible molecular segments exist in the copolymer's molecular chain. Under external impact, these flexible segments act as stress-relief points, mitigating the impact. Furthermore, introducing other flexible molecular segments into the otherwise regular polymer molecular chain disrupts the regularity of the PGA polymer structure, reducing brittleness and increasing toughness. Since PCL molecular segments also possess a certain degree of regularity and high crystallinity, as the caprolactone content in the copolymer increases, the regularity of the copolymer's molecular chain structure increases, resulting in a more orderly arrangement of molecular chains. Consequently, with increasing caprolactone content, the copolymer's brittleness gradually increases, while its toughness decreases.

[0074] As shown in Table 1, when the amount of caprolactone in the copolymer with glycolide and caprolactone as monomers is 30%, the toughness of PGA is significantly improved, and it has good comprehensive mechanical properties. It also has high strength and high toughness, making it a good bio-based biodegradable material.

[0075] This invention describes in detail the experimental process and scheme for toughening modified polyglycolic acid materials. However, this invention includes, but is not limited to, this invention. Within the scope of the concept involved in this invention, simple combinations of the experimental scheme and other methods in this invention are all considered to be the content disclosed in this invention and are within the protection scope of this invention.

Claims

1. A toughened modified polyglycolic acid material, comprising a reaction product of a polyglycolic acid block copolymer and a sulfur-containing compound, wherein the polyglycolic acid block copolymer is a polymerization product of glycolide, another cyclic lactone and an unsaturated small molecule polyol. 2.The toughened modified polyglycolic acid material according to claim 1, wherein the another cyclic lactone is at least one selected from C 3-C 12 cyclic lactones, preferably at least one selected from lactide, caprolactone, butyrolactone, heptalactone and octalactone; and / or the unsaturated small molecule polyol is at least one selected from α-allyl glyceryl ether, trimethylolpropane monoallyl ether and 1,4-butenediol; and / or the sulfur-containing compound is at least one selected from sulfur, dicumyl peroxide, dibenzoyl peroxide and ethanedithiol. The toughened modified polyglycolic acid material is obtained by vulcanization of the polyglycolic acid block copolymer and the sulfur-containing compound. The method comprises the following steps: (1) polymerizing the components including glycolide, another cyclic lactone and unsaturated small molecule polyol in the presence of a catalyst to obtain a polyglycolic acid block copolymer; and 3. A method of making the toughened modified polyglycolic acid material of any one of claims 1 or 2, comprising: (2) vulcanizing the polyglycolic acid block copolymer obtained in step (1) and the sulfur-containing compound to obtain the toughened modified polyglycolic acid material.

4. The production method according to claim 3, characterized by, 5.The method according to claim 4, wherein the another cyclic lactone is at least one selected from C 3-C 12 cyclic lactones, preferably at least one selected from lactide, caprolactone, butyrolactone, heptalactone and octalactone; and / or the unsaturated small molecule polyol is at least one selected from α-allyl glyceryl ether, trimethylolpropane monoallyl ether and 1,4-butenediol; and / or the catalyst is at least one selected from 4-diaminopyridine, phosphorus, thiourea, 1.5,7-triazido bicyclo(4,4,0)decane-5-ene, ferric chloride, aluminum chloride, sodium alcoholate, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin bis(dodecylthio), tin tetrachloride, stannous chloride, stannous acetate and tin oxide, preferably at least one selected from stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin bis(dodecylthio) and tin tetrachloride; and / or the sulfur-containing compound is at least one selected from sulfur, dicumyl peroxide, dibenzoyl peroxide and ethanedithiol. 6.The method according to claim 4, wherein the amount of glycolide is 30-90 parts, the amount of another cyclic lactone is 10-70 parts and the amount of unsaturated small molecule polyol is 0.5-8 parts, based on 100 parts by weight of the total amount of glycolide and another cyclic lactone; preferably, the amount of glycolide is 50-90 parts, the amount of another cyclic lactone is 10-50 parts and the amount of unsaturated small molecule polyol is 1-5 parts, based on 100 parts by weight of the total amount of glycolide and another cyclic lactone. ​ ​ ​ ​ ​ ​ ​ ​ The amount of the catalyst is 0.1-6 parts, preferably 1-3 parts, based on 100 parts by weight of the total weight of the glycolide and other cyclic lactones; and / or, The amount of the sulfur-containing compound is 0.5-6 parts, preferably 2-4 parts, based on 100 parts by weight of the total weight of the glycolide and other cyclic lactones.

7. The preparation method according to claim 4, characterized in that, In the step (1), The components including the glycolide, other cyclic lactones and unsaturated small-molecule polyols are heated to form a homogeneous phase before the polymerization reaction.

8. The production method according to claim 7, characterized by, The heating condition is that the heating temperature is 50-150°C and the heating time is 0.5-1.5 h; preferably, the heating condition is that the heating temperature is 80-100°C and the heating time is 0.8-1.2 h.

9. The preparation method according to claim 4, characterized in that, The polymerization reaction condition in the step (1) is that the reaction is carried out at 90-100°C for 40-60 min; and / or, after the polymerization reaction, a drying step is further included, preferably, the drying temperature is 50-60°C.

10. The preparation method according to claim 4, characterized in that, The sulfurization reaction condition in the step (2) is that the reaction is carried out at 160-180°C for 15-45 min.

Images