High-strength and high-toughness polyglycolic acid grafted copolymer as well as preparation method and application thereof

Abstract

The invention relates to the field of high polymer materials, and provides a high-strength and high-toughness polyglycolic acid grafted copolymer as well as a preparation method and application thereof. The high-strength and high-toughness polyglycolic acid graft copolymer provided by the invention comprises polyglycolic acid and a graft copolymer of a graft comonomer, and a side chain of the graft copolymer contains R3 which is substituted or unsubstituted alkyl or alkoxy or alkenyl or aralkyl or alkaryl. Through a grafting reaction process, the polyglycolic acid resin with synergistically improved mechanical strength and toughness is obtained. The invention provides an effective solution for preparing the intrinsic high-toughness PGA.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to a high-strength and high-toughness polyglycolic acid graft copolymer, its preparation method, and its application. Background Technology

[0002] Among known biodegradable polyester materials, polyglycolic acid (PGA) is a highly crystalline polyester polymer with the fewest monomer carbons and rapid, complete degradation. Compared to aliphatic and aromatic biodegradable polyesters, polylactic acid, and polyhydroxyalkanoates, PGA offers advantages such as high strength, high modulus, and excellent gas barrier properties. Furthermore, due to its excellent biocompatibility, it is widely used in high-value-added biomedical fields such as surgical sutures and artificial bones. However, compared to other flexible biodegradable polyesters, PGA is more brittle and prone to fracture, severely limiting its processing applications in many fields. Therefore, toughening modification of PGA crystal structure is essential.

[0003] To address the poor toughness of PGA, exogenous (additive) toughening modification methods are commonly employed. This involves adding flexible or elastomers to PGA to improve its mechanical toughness. Chinese patent CN 114075377A discloses a toughening polyglycolic acid composition comprising 40-90 parts PGA, 10-60 parts polyurethane, and 0.5-10 parts isocyanate compounds. Due to the reduced dispersion size of the polyurethane elastomer in this PGA composition, the notched impact strength of the PGA is significantly improved. Chinese patent CN114163791A addresses the compatibility issue of exogenous (additive) toughening modification of PGA by adding a suitable toughening resin to PGA and using a modifier to increase the compatibility between the two resins. While using additive fillers can significantly improve the toughness of PGA, it also introduces problems such as incomplete degradation of the composition and mismatches in interfacial compatibility. Currently, there are few research methods for improving PGA toughness from its intrinsic structure. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a polyglycolic acid graft copolymer with improved impact toughness, its preparation method, and its applications. This invention utilizes melt extrusion copolymerization to introduce side chains into the regular structure of polyglycolic acid (PGA), weakening the regularity of the PGA chain arrangement and potentially generating a moderately crosslinked network, thereby achieving a synergistic improvement in the mechanical strength and impact toughness of the PGA graft copolymer.

[0005] One objective of this invention is to provide a high-strength, high-toughness polyglycolic acid graft copolymer, comprising: a graft copolymer of polyglycolic acid and a graft comonomer, wherein the side chains of the graft copolymer contain Wherein, R3 is a substituted or unsubstituted alkyl, alkoxy, alkenyl, aralkyl, or alkylaryl group, and the substituent group in R3 is a halogen, -OH, -NH2, =O, C1-C. 12 Alkyl groups, C3-C6 cycloalkyl groups, C1-C 12 alkoxy groups, C1-C 12 At least one of the acyl groups.

[0006] According to the present invention, in the high-strength and high-toughness polyglycolic acid graft copolymer:

[0007] The graft copolymer monomer is at least one monomer having the following structure or an oligomer or copolymer containing monomers with the following structure:

[0008]

[0009] In formula (1), R1 is one of hydrogen atom, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, R2 is one of hydrogen atom, hydroxyl group, substituted or unsubstituted alkyl group or alkoxy group, and R3 is one of substituted or unsubstituted alkyl group or alkoxy group or alkenyl group or aralkyl group; preferably, in formula (1), R1 is selected from hydrogen atom, substituted or unsubstituted C1-C1 group. 20 R2 is selected from one of the alkyl or alkoxy groups, and R2 is selected from hydrogen atoms, substituted or unsubstituted C1-C atoms. 20 R3 is one of the alkyl or alkoxy groups, and R3 is selected from substituted or unsubstituted C1-C1 groups. 20 R1 is selected from one of alkyl, alkoxy, alkenyl, aralkyl, or alkylaryl groups; more preferably, in formula (1), R1 is selected from one of hydrogen atoms, substituted or unsubstituted C1-C6 alkyl or alkoxy groups; R2 is selected from one of hydrogen atoms, substituted or unsubstituted C1-C6 alkyl or alkoxy groups; R3 is a substituted or unsubstituted C1-C6 alkyl or alkoxy group, substituted or unsubstituted C6-C6 alkyl or alkoxy group, or a substituted or unsubstituted C6-C6 alkyl or alkoxy group. 12 One of aryl or alkylaryl groups; wherein, in R1, R2, and R3, the substituents are independently selected from halogens, -OH, -NH2, =O, C1-C. 12 Alkyl groups, C3-C6 cycloalkyl groups, C1-C 12 alkoxy groups, C1-C 12 One of the acyl groups.

[0010] According to the present invention, in the high-strength and high-toughness polyglycolic acid graft copolymer:

[0011] The polyglycolic acid has a weight-average molecular weight of 100,000 to 1,000,000 g / mol and a molecular weight distribution index (PDI) of 1.5 to 5; preferably, the polyglycolic acid has a weight-average molecular weight of 100,000 to 500,000 g / mol and a molecular weight distribution index (PDI) of 2 to 3.

[0012] The intrinsic viscosity of the polyglycolic acid is 0.9 to 7 dl / g. For example, the intrinsic viscosity can be any value among 0.9 dl / g, 1 dl / g, 2 dl / g, 2.5 dl / g, 3 dl / g, 3.5 dl / g, 4 dl / g, 4.5 dl / g, 5 dl / g, 5.5 dl / g, 6 dl / g, 6.5 dl / g, and 7 dl / g, or any value within any two of the above ranges. Preferably, the intrinsic viscosity of the polyglycolic acid is 1 to 5 dl / g.

[0013] The melt flow rate of the polyglycolic acid measured at 230°C and 2.16 kg is 1–200 g / 10 min. For example, the melt index of the polyglycolic acid is any value among 1 g / 10 min, 5 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, 100 g / 10 min, 150 g / 10 min, and 200 g / 10 min, or any value within any two of the above ranges. Preferably, the melt flow rate of the polyglycolic acid measured at 230°C and 2.16 kg is 20–100 g / 10 min.

[0014] The second objective of this invention is to provide a method for preparing the above-mentioned high-strength and high-toughness polyglycolic acid graft copolymer, comprising: melting and reacting components including polyglycolic acid and graft copolymer monomers under the action of a free radical initiator to obtain the high-strength and high-toughness polyglycolic acid graft copolymer.

[0015] According to the present invention, in the preparation method of the high-strength and high-toughness polyglycolic acid graft copolymer:

[0016] The polyglycolic acid needs to be pre-dried. The drying can be carried out using drying equipment and conditions commonly used in the art, such as vacuum drying or hot air drying. Preferably, the pre-drying temperature is 50-150°C, and more preferably 80-120°C. The water content of the dried polyglycolic acid is less than 100 ppm, and more preferably less than 80 ppm.

[0017] The melt reaction extrusion operation can be implemented using a twin-screw extruder. Specifically, the conditions for the melt reaction are: a reaction temperature of 150–280°C and an extruder speed of 50–1200 rpm; preferably, the reaction temperature is 170–250°C and the extruder speed is 100–500 rpm. After melt reaction extrusion, the obtained material can be cooled, granulated, and packaged using conventional operations, wherein cooling can be achieved by air cooling or water cooling.

[0018] According to the present invention, in the preparation method of the high-strength and high-toughness polyglycolic acid graft copolymer:

[0019] The amount of the grafted comonomer is 1 to 30 wt% of polyglycolic acid, preferably 1 to 12 wt%.

[0020] The ratio of the free radical initiator to the total amount of polyglycolic acid and graft copolymer monomer is less than 0.7:1, preferably (0.01~0.5):1;

[0021] The free radical initiator is selected from at least one of peroxide free radical initiators, sulfide free radical initiators, and azo free radical initiators. Specifically, the peroxide free radical initiator is preferably selected from at least one of acyl peroxides, alkyl peroxides, aromatic substituted alkyl peroxides, peresters, alkyl hydrogen peroxides, and ketone peroxides; the sulfide free radical initiator is preferably selected from at least one of diisopropyl dithiocarbonate and dipropyl dithiocarbonate; and the azo compound is preferably azobisisobutyronitrile (AIBN). Further, the acyl peroxide is more preferably benzoyl peroxide; the alkyl peroxide is more preferably dialkyl peroxide, such as at least one of bis-tert-butyl peroxide, bis-isopropylphenyl peroxide, isopropylphenyl peroxide-butyl, 3,3,5-trimethylcyclohexane-1,1-diperoxy-tert-butyl, and 2,5-di-tert-butylperoxyhexane; the aromatic substituted alkyl peroxide is more preferably aromatic substituted dialkyl peroxide, such as 2,3-dimethyl-2,3-diphenylbutane; the perester is more preferably at least one of trimethylacetic acid-tert-butyl peroxide, 2-ethylhexanoate-tert-butyl peroxide, benzoate-tert-butyl peroxide, and dodecanoic acid peroxide; the alkyl hydrogen peroxide is more preferably at least one of tert-butyl hydrogen peroxide and cumene hydrogen peroxide; and the peroxide ketone is more preferably methyl ethyl ketone peroxide.

[0022] A third objective of this invention is to provide a high-strength, high-toughness polyglycolic acid graft copolymer composition, comprising a mixture of the high-strength, high-toughness polyglycolic acid graft copolymer and processing aids and / or reaction products, wherein the high-strength, high-toughness polyglycolic acid graft copolymer is the high-strength, high-toughness polyglycolic acid graft copolymer described in one objective of this invention or the high-strength, high-toughness polyglycolic acid graft copolymer obtained by the preparation method described in another objective of this invention.

[0023] According to the present invention, in the high-strength and high-toughness polyglycolic acid graft copolymer composition, the processing aid is selected from at least one of chain extenders, antioxidants, and anti-hydrolysis agents.

[0024] The chain extender is one or more of the following: a compound with a group that is reactive with a carboxyl or hydroxyl group, a polymer with a group that is reactive with a carboxyl or hydroxyl group, and a compound containing at least two epoxy functional groups. Preferably, the chain extender is selected from at least one of a difunctional isocyanate compound and a difunctional epoxy compound, more preferably from at least one of toluene diisocyanate, hexamethylene diisocyanate, and a copolymer containing polyepoxy groups (e.g., BASF ADR 4370). The weight-average molecular weight of the copolymer containing polyepoxy groups is 3000-9000 g / mol, and the epoxy equivalent is 200-500 g / mol.

[0025] The antioxidant is selected from at least one of hindered phenolic antioxidants, hindered amine antioxidants, phosphite antioxidants, and thiol antioxidants; preferably, the hindered phenolic antioxidant is selected from 2,6-di-tert-butyl-4-methylphenol, pentaerythritol [β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and N,N'-bis[β-(3,5-di-tert-butyl] At least one of [β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]hydrazine, 2,6-di-tert-butyl-p-cresol, and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, more preferably pentaerythritol ester of [β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], n-octadecyl ester of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and N,N'-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]hydrazine. At least one of the following: the phosphite antioxidant is selected from at least one of tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-dicumylphenyl) pentaerythritol diphosphite, bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite, and pentaerythritol diphosphite bisoctadecyl ester, more preferably tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-dicumylphenyl) pentaerythritol diphosphite, and bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite. At least one of pentaerythritol diphosphite (phenol); the thiol antioxidant is selected from at least one of dilauryl 3,3-thiodipropionate, dioctadecyl thiodipropionate, dimyristyl 3,3'-thiodipropionate, ditridecyl 3,3'-thiodipropionate, 4,4'-thiobis(6-tert-butyl-3-methylphenol), and thiodi-2,1-ethylene glycol 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate.

[0026] The anti-hydrolysis agent is selected from at least one of carbodiimide type, isocyanate, epoxy compound, oxazoline, and acid anhydride, preferably at least one of bis(2,6-diisopropylbenzene)carbodiimide, polycarbodiimide, 2,2-bis(2-oxazoline), 2-propyl-2-oxazoline, and 4,4-dimethyl-2-oxazoline;

[0027] The processing aid in the composition is 0.1-10 wt%, preferably 0.1-5 wt%, by mass percentage. The amounts of chain extender, antioxidant, and anti-hydrolysis agent in the processing aid can be added according to commonly used amounts in the prior art, based on actual needs. For example, the amount of chain extender can be 0.01-2 wt%, the amount of antioxidant can be 0.01-3 wt%, and the amount of anti-hydrolysis agent can be 0.01-5 wt%.

[0028] The fourth objective of this invention is to provide a method for preparing the above-mentioned high-strength and high-toughness polyglycolic acid graft copolymer composition, comprising the step of mixing the high-strength and high-toughness polyglycolic acid graft copolymer with a processing aid; preferably, it comprises: melting and extruding the components including polyglycolic acid, graft copolymer monomer, free radical initiator, and processing aid to obtain the high-strength and high-toughness polyglycolic acid graft copolymer composition.

[0029] According to the present invention, in the preparation method of the high-strength and high-toughness polyglycolic acid graft copolymer composition:

[0030] The free radical initiator is selected from at least one of peroxide free radical initiators, sulfide free radical initiators, and azo free radical initiators;

[0031] Based on a total mass percentage of 100 wt% for all materials, the polyglycolic acid comprises 65–98.89 wt%, preferably 82–98.89 wt%; the graft copolymer monomer comprises 1–20 wt%, preferably 1–10 wt%; the free radical initiator comprises 0.01–5 wt%, preferably 0.01–3 wt%; and the processing aid comprises 0.1–10 wt%, preferably 0.1–5 wt%.

[0032] The conditions for the melting reaction are: temperature of 150-280℃ and rotation speed of 50-1200 rpm; preferably, temperature of 170-250℃ and rotation speed of 100-500 rpm.

[0033] The fifth objective of this invention is to provide an application of the above-mentioned high-strength, high-toughness polyglycolic acid graft copolymer or the above-mentioned high-strength, high-toughness polyglycolic acid graft copolymer composition in blown film, cast film, multilayer film, sheet, fiber, and injection-molded products. The application fields are not specifically limited, including but not limited to applications in pharmaceuticals, daily necessities, oil extraction, etc., and more specifically, it can be applied to products such as film bags, sheets, injection-molded parts, straws, and lunch boxes.

[0034] According to the present invention, the blown film and cast film can be processed into films using equipment and processes commonly used in the art, and then cooled, shaped, stretched and wound into thin films; the injection molded parts can be processed using commonly used injection molding machines, and obtained through injection molding and demolding.

[0035] The polyglycolic acid (PGA) used in this invention, also known as polyhydroxyacetic acid, is the simplest thermoplastic linear aliphatic polyester. PGA can be prepared by methods such as glycolic acid melt polycondensation or glycolide ring-opening polymerization. It is a typical highly crystalline polymer with a stable crystal lattice, a high melting point, and advantages in mechanical strength. However, due to its high crystallinity, its high brittleness limits its application in more flexible scenarios during processing and use. This invention involves melt grafting modification of PGA. Under specific process conditions and the action of functional monomers, the resulting PGA graft copolymer composition significantly improves impact toughness while maintaining high mechanical strength. Detailed Implementation

[0036] 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.

[0037] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0038] Source of raw materials

[0039] All raw materials used in the examples and comparative examples are commercially available.

[0040] Polyglycolic acid (PGA), manufactured by Shenzhen Boli Biomaterials Co., Ltd., had a melt flow rate of 96 g / 10 min measured at 230°C and 2.16 kg. In the examples and comparative examples, the PGA was pre-dried at 80°C, resulting in a water content of less than 100 ppm.

[0041] Butyl methacrylate, Chinese pharmaceutical reagent grade.

[0042] Vinyl propionate, Chinese pharmaceutical reagent grade.

[0043] Vinyl butyrate, Chinese pharmaceutical reagent grade.

[0044] Vinyl cinnamate, Chinese pharmaceutical reagent grade.

[0045] Cumene hydroperoxide, Chinese pharmaceutical reagent grade.

[0046] 1,3-Bis(tert-butylperoxyisopropyl)benzene, Chinese pharmaceutical reagent grade.

[0047] Antioxidant 1010, Nanjing Jingtianwei Chemical Co., Ltd.

[0048] Chain extender ADR 4370, BASF.

[0049] The performance of this invention was determined using the following method:

[0050] Melt flow rate test: Measured using an Instron CEAST melt flow indexer according to ISO 1133 standard. The barrel temperature was 230℃, the weight load was 2.16 kg, the die diameter was 2.095 mm and the length was 8 mm, the preheating time was 240 s, and samples were automatically cut at set intervals. Five samples were taken and the average value was calculated. The result was expressed as grams per 10 minutes (g / 10 min).

[0051] Thermogravimetric analysis (TGA): Tests were performed on a THERMALAYSIS Discovery series thermogravimetric analyzer using TA Instruments Trios version 3.1.4 software. Before testing, the analyzer was preheated until the balance chamber temperature stabilized at 40°C. During testing, 5–10 mg of sample was weighed and placed in a ceramic crucible. The test was conducted in an air atmosphere with a flow rate of 20 mL / min, with a heating range of 30–600°C and a heating rate of 10°C / min. The weight loss curves of the samples were recorded.

[0052] Mechanical tensile testing: Tests were conducted according to ISO 527-3 standards using an INSTRON 3344 universal testing machine with Bluehill version 2.31 software. Standard specimens of type 5-A and 80×10×4mm dimensions from ISO 527-2 were injection molded using a micro-injection molding machine. Before testing, specimens were placed in a BluepADR BPS-100CB constant temperature and humidity chamber (23℃, 50% relative humidity) at Shanghai Yiheng Scientific Instruments Co., Ltd. for 24 hours. During testing, the initial clamp spacing was 50mm, the tensile rate was 50mm / min, and each sample was tested 5 times, with the average value taken.

[0053] Impact strength test: In accordance with ISO 179 / 1e standard, the samples were placed in a BluepADR BPS-100CB constant temperature and humidity chamber (temperature 23℃, relative humidity 50%) of Shanghai Yiheng Scientific Instruments Co., Ltd. for 24 hours before the test. A 2J pendulum was used for the test, and each sample was tested 5 times, and the average value was taken.

[0054] Comparative Example 1

[0055] Polyglycolic acid (PGA) was extruded into a co-rotating twin-screw extruder from Labtech, Sweden, at 200 rpm. The extrusion temperatures were 190°C, 220°C, 230°C, 240°C, 240°C, 240°C, 240°C, 240°C, 230°C, and 225°C. The extruder was equipped with a 3mm diameter circular die. After extrusion and air cooling, the sample was pelletized into cylindrical yellow particles approximately 3mm in length, known as PGA particles A. At 230°C and 2.16kg, the melt flow rate was extremely high, and the melt flow index could not be measured. The particles were collected, packaged, and stored for later use.

[0056] Comparative Example 2

[0057] Polyglycolic acid (PGA), antioxidant 1010, and chain extender ADR 4370 were premixed at a mass fraction of 99.7:0.2:0.1. The mixture was extruded using a co-rotating twin-screw extruder from Labtech (Sweden) at 200 rpm at the following temperatures: 190℃, 220℃, 230℃, 240℃, 240℃, 240℃, 240℃, 240℃, 230℃, and 225℃. The extruder was equipped with a 3mm diameter circular die. After extrusion and air cooling, the samples were pelletized into cylindrical yellow particles approximately 3mm in length, known as PGA-modified particles B. Static analysis at 230℃ and 2.16kg showed a melt flow rate of 62.8g / 10min. The particles were collected and packaged for later use.

[0058] Comparative Example 3

[0059] Polyglycolic acid, butyl methacrylate, cumene hydroperoxide, and antioxidant 1010 were premixed thoroughly at a mass fraction of 97.5:2.2:0.1:0.2 and polymerized using a co-rotating twin-screw extruder from Labtech, Sweden. The extrusion speed was 200 rpm, and the extrusion temperatures were 190℃, 220℃, 230℃, 240℃, 240℃, 240℃, 240℃, 240℃, 230℃, and 225℃. The extruder was equipped with a 3mm diameter circular die. After extrusion and air cooling, the samples were pelletized into cylindrical yellow particles approximately 3mm in length, known as PGA-modified particles C. The melt flow rate at 230℃ and 2.16kg was measured to be 56.3g / 10min. The particles were collected and packaged for later use.

[0060]

Example 1

[0061] Polyglycolic acid, vinyl propionate, 1,3-bis(tert-butylperoxyisopropyl)benzene, and antioxidant 1010 were premixed thoroughly at a mass fraction of 97.5:2.2:0.1:0.2 and polymerized using a co-rotating twin-screw extruder from Labtech, Sweden. The extrusion speed was 200 rpm, and the extrusion temperatures were 190℃, 220℃, 230℃, 240℃, 240℃, 240℃, 240℃, 240℃, 230℃, and 225℃. The extruder was equipped with a 3mm diameter circular die. After extrusion and air cooling, the samples were pelletized into cylindrical yellow particles approximately 3mm in length, known as PGA-modified particles D. The melt flow index was measured to be 92g / 10min at 230℃ and 2.16kg. The particles were collected and packaged for later use.

[0062]

Example 2

[0063] Polyglycolic acid, vinyl propionate, cumene hydroperoxide, and antioxidant 1010 were premixed thoroughly at a mass fraction of 97.5:2.2:0.1:0.2 and polymerized using a co-rotating twin-screw extruder from Labtech, Sweden. The extrusion speed was 200 rpm, and the extrusion temperatures were 190℃, 220℃, 230℃, 240℃, 240℃, 240℃, 240℃, 240℃, 230℃, and 225℃. The extruder was equipped with a 3mm diameter circular die. After extrusion and air cooling, the samples were pelletized into cylindrical yellow particles approximately 3mm in length, i.e., PGA-modified particles E. The melt index was measured to be 46g / 10min at 230℃ and 2.16kg. The particles were collected and packaged for later use.

[0064]

Example 3

[0065] Polyglycolic acid, vinyl butyrate, cumene hydroperoxide, and antioxidant 1010 were premixed thoroughly at a mass fraction of 97.5:2.2:0.1:0.2 and polymerized using a co-rotating twin-screw extruder from Labtech, Sweden. The extrusion speed was 200 rpm, and the extrusion temperatures were 190℃, 220℃, 230℃, 240℃, 240℃, 240℃, 240℃, 240℃, 230℃, and 225℃. The extruder was equipped with a 3mm diameter circular die. After extrusion and air cooling, the samples were pelletized into cylindrical yellow particles approximately 3mm in length, known as PGA-modified particles F. The melt flow index was measured at 230℃ and 2.16kg to be 46g / 10min. The particles were collected and packaged for later use.

[0066]

Example 4

[0067] Polyglycolic acid, vinyl cinnamate, cumene hydroperoxide, and antioxidant 1010 were premixed thoroughly at a mass fraction of 97.5:2.2:0.1:0.2 and polymerized using a co-rotating twin-screw extruder from Labtech, Sweden. The extrusion speed was 200 rpm, and the extrusion temperatures were 190℃, 220℃, 230℃, 240℃, 240℃, 240℃, 240℃, 240℃, 230℃, and 225℃. The extruder was equipped with a 3mm diameter circular die. After extrusion and air cooling, the samples were pelletized into cylindrical yellow particles approximately 3mm in length, known as PGA-modified particles G. The melt flow index was measured at 230℃ and 2.16kg to be 46g / 10min. The particles were collected and packaged for later use.

[0068]

Example 5

[0069] Polyglycolic acid, vinyl propionate, cumene hydroperoxide, antioxidant 1010, and chain extender ADR4370 were premixed at a mass fraction of 98.21:0.98:0.66:0.15 and polymerized using a co-rotating twin-screw extruder from Labtech, Sweden. The extrusion speed was 100 rpm, and the extrusion temperatures were 190℃, 220℃, 230℃, 240℃, 240℃, 240℃, 240℃, 240℃, 230℃, and 225℃. The extruder was equipped with a 3mm diameter circular die. After extrusion and air cooling, the samples were pelletized into cylindrical yellow particles approximately 3mm in length, known as PGA-modified particles H. At 230℃ and 2.16kg, the melt flow index was measured to be 5g / 10min. The particles were collected, packaged, and stored for later use.

[0070]

Example 6

[0071] Polyglycolic acid, vinyl propionate, cumene hydroperoxide, antioxidant 1010, and chain extender ADR 4370 were premixed at a mass fraction of 96.22:2.89:0.145:0.6:0.145 and polymerized using a co-rotating twin-screw extruder from Labtech, Sweden. The extrusion speed was 100 rpm, and the extrusion temperatures were 190℃, 220℃, 230℃, 240℃, 240℃, 240℃, 240℃, 240℃, 230℃, and 225℃. The extruder was equipped with a 3mm diameter circular die. After extrusion and air cooling, the samples were pelletized into cylindrical yellow particles approximately 3mm in length, known as PGA modified particles I. The melt flow index was measured at 230℃ and 2.16kg, with a value of 13g / 10min. The particles were collected, packaged, and stored for later use.

[0072]

Example 7

[0073] Polyglycolic acid, vinyl butyrate, cumene hydroperoxide, antioxidant 1010, and chain extender ADR 4370 were premixed at a mass fraction of 98.21:0.98:0.66:0.15 and polymerized using a co-rotating twin-screw extruder from Labtech, Sweden. The extrusion speed was 100 rpm, and the extrusion temperatures were 190℃, 220℃, 230℃, 240℃, 240℃, 240℃, 240℃, 240℃, 230℃, and 225℃. The extruder was equipped with a 3mm diameter circular die. After extrusion and air cooling, the samples were pelletized into cylindrical yellow particles approximately 3mm in length, known as PGA-modified particles G. The melt flow index was measured at 230℃ and 2.16kg, with a value of 18.3g / 10min. The particles were collected, packaged, and stored for later use.

[0074]

Example 8

[0075] Preparation of polyglycolic acid injection molded specimens:

[0076] The particles from Examples 1-7 and Comparative Examples 1-3 were thoroughly dried and then processed at HAAKE manufactured by Thermo Fisher Scientific Inc. in the United States. TM The molding process was performed on a MiniJet II micro injection molding machine. The molds used were Thermo Fisher Scientific models 557-2298 ISO 527-2-5A and 557-2300-80×10×4mm. During the experiment, the cavity temperature and mold temperature were set to 230℃ and 70℃, respectively. The injection pressure was set to 300 bar for 5 seconds, followed by a holding pressure of 100 bar for 20 seconds, after which the molded sample was demolded and collected.

[0077]

Test Example 1

[0078] The polyglycolic acid resin particles prepared in Examples 1-7 and Comparative Examples 1-3 were subjected to thermogravimetric analysis (TGA) according to the steps described above, and the results are shown in Table 1.

[0079] Table 1. Thermogravimetric temperatures of polyglycolic acid resin composition particles obtained in the examples and comparative examples

[0080] Sample TGA (5%) / ℃ Comparative Example 1 263 Comparative Example 2 279 Comparative Example 3 274 Example 1 320 Example 2 312 Example 3 350 Example 4 350 Example 5 346 Example 6 336 Example 7 345

[0081] As shown in Table 1, the introduction of unsaturated functional monomers into PGA through melt grafting significantly improved the thermal stability of the PGA graft copolymer compared to screw-grown PGA (Comparative Example 1) and chain-extended PGA (Comparative Example 2). Compared to screw-grown PGA particles (Comparative Example 1), the thermal stability of the PGA composition after the grafting reaction was significantly improved. d5％The temperature was increased by at least 39°C. With the same amount of reactant and initiator, the functional monomer structures used in Examples 1-7 showed a superior effect on improving the thermal stability of PGA compared to acrylate monomers (Comparative Example 3).

[0082]

Test Example 2

[0083] The PGA injection-molded specimens prepared in Example 8 were subjected to mechanical strength and unnotched impact strength tests as described above, and the values ​​are listed in Table 2.

[0084] Table 2. Mechanical properties of PGA specimens in comparative and example studies

[0085]

[0086] The results of tensile mechanics and unnotched impact strength tests on PGA spline show that unmodified PGA is notch-sensitive and brittle, with significantly insufficient tensile and impact toughness. Chain extension can improve the unnotched impact strength of PGA (from the original 6 kJ / m). 2 Increased to 12.9 kJ / m 2 The tensile strength was increased by 32%. However, the elongation at break remained largely unchanged. When only butyl methacrylate monomer was used for graft modification, although the tensile strength and elongation at break of PGA increased by 46% and 400% respectively compared to the unmodified PGA, the impact strength was slightly lower than that of the unmodified PGA. This indicates that the optimal comprehensive mechanical properties cannot be achieved using this monomer. However, after grafting with the unsaturated functional monomer of the structure described in this invention, Examples 1-7 show a synergistic increase in the mechanical tensile strength (tensile strength increased by at least 50%), elongation at break (increased by at least 40%), and unnotched impact strength of PGA. Furthermore, when both the grafted monomer and the chain extender were added simultaneously, the mechanical strength, elongation at break, and unnotched impact strength of the modified PGA were significantly improved compared to the raw material (Comparative Example 1) and when only the chain extender was added (Comparative Example 2). This indicates that the grafting and chain extension processes of the structural monomers described in this invention produce a coupled strengthening and toughening effect, resulting in a significant improvement in tensile properties and impact toughness. This has practical significance for the actual production and application of extended PGA products. Therefore, regardless of whether the modified system contains chain extenders, the structural monomers described in this invention have synergistic strengthening and toughening effects.

Claims

1. A high-strength, high-toughness polyglycolic acid graft copolymer, comprising: A graft copolymer of polyglycolic acid and a graft copolymer monomer, wherein the side chains of the graft copolymer contain Wherein, R3 is a substituted or unsubstituted alkyl, alkoxy, alkenyl, aralkyl, or alkylaryl group, and the substituent group in R3 is a halogen, -OH, -NH2, =O, C1-C. 12 Alkyl groups, C3-C6 cycloalkyl groups, C1-C 12 alkoxy groups, C1-C 12 At least one of the acyl groups.

2. The high-strength, high-toughness polyglycolic acid graft copolymer according to claim 1, characterized in that, The graft copolymer monomer is at least one monomer having the following structure or an oligomer or copolymer containing monomers with the following structure: In formula (1), R1 is one of hydrogen atom, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, R2 is one of hydrogen atom, hydroxyl group, substituted or unsubstituted alkyl group or alkoxy group, and R3 is one of substituted or unsubstituted alkyl group or alkoxy group or alkenyl group or aralkyl group or alkylaryl group.

3. The high-strength, high-toughness polyglycolic acid graft copolymer according to claim 2, characterized in that, In formula (1), R1 is selected from hydrogen atoms, substituted or unsubstituted C1-C atoms. 20 R2 is selected from one of the alkyl or alkoxy groups, and R2 is selected from hydrogen atoms, substituted or unsubstituted C1-C atoms. 20 R3 is one of the alkyl or alkoxy groups, and R3 is selected from substituted or unsubstituted C1-C1 groups. 20 One of alkyl, alkoxy, alkenyl, aralkyl, or alkylaryl; Preferably, R1 is selected from one of hydrogen atoms, substituted or unsubstituted C1-C6 alkyl or alkoxy groups; R2 is selected from one of hydrogen atoms, substituted or unsubstituted C1-C6 alkyl or alkoxy groups; R3 is a substituted or unsubstituted C1-C6 alkyl or alkoxy or alkenyl group, substituted or unsubstituted C6-C 12 One of aryl or alkylaryl; In R1, R2, and R3, the substituents are independently selected from halogens, -OH, -NH2, =O, and C1-C. 12 Alkyl groups, C3-C6 cycloalkyl groups, C1-C 12 alkoxy groups, C1-C 12 One of the acyl groups.

4. A method for preparing the high-strength, high-toughness polyglycolic acid graft copolymer according to any one of claims 1 to 3, comprising: The components, including polyglycolic acid and graft copolymer monomers, are melted and reacted under the action of a free radical initiator to obtain the high-strength and high-toughness polyglycolic acid graft copolymer.

5. The preparation method according to claim 4, characterized in that, The polyglycolic acid, measured at 230°C and 2.16 kg, has a melt flow rate of 1–200 g / 10 min, preferably 20–100 g / 10 min; and / or, The polyglycolic acid described herein needs to be pre-dried. Preferably, the pre-drying temperature is 50–150°C, more preferably 80–120°C; the water content of the dried polyglycolic acid is less than 100 ppm, preferably less than 80 ppm; and / or, The melt reaction is achieved using a twin-screw extruder. Preferably, the conditions for the melt reaction are: a reaction temperature of 150–280°C and an extruder speed of 50–1200 rpm; more preferably, the conditions for the melt reaction are: a reaction temperature of 170–250°C and an extruder speed of 100–500 rpm.

6. The preparation method according to claim 4, characterized in that, The amount of the grafted comonomer is 1-30 wt% of polyglycolic acid, preferably 1-12 wt%; and / or, The free radical initiator is selected from at least one of peroxide free radical initiators, sulfide free radical initiators, and azo free radical initiators; and / or, The ratio of the free radical initiator to the total amount of polyglycolic acid and graft copolymer monomer is less than 0.7:1, preferably (0.01~0.5):

1.

7. A high-strength, high-toughness polyglycolic acid graft copolymer composition, comprising a mixture of a high-strength, high-toughness polyglycolic acid graft copolymer and a processing aid and / or a reaction product, wherein the high-strength, high-toughness polyglycolic acid graft copolymer is the high-strength, high-toughness polyglycolic acid graft copolymer according to any one of claims 1 to 3 or the high-strength, high-toughness polyglycolic acid graft copolymer obtained by the preparation method according to any one of claims 4 to 6.

8. The high-strength, high-toughness polyglycolic acid graft copolymer composition according to claim 7, characterized in that, The processing aid is selected from at least one of chain extenders, antioxidants, and anti-hydrolysis agents; and / or, The composition contains 0.1 to 10 wt% of processing aids, preferably 0.1 to 5 wt%, by weight percentage.

9. The high-strength, high-toughness polyglycolic acid graft copolymer composition according to claim 8, characterized in that, The chain extender is selected from at least one of difunctional isocyanate compounds and difunctional epoxy compounds, preferably from at least one of toluene diisocyanate, hexamethylene diisocyanate, and copolymers containing polyepoxy groups; and / or, The antioxidant is selected from at least one of hindered phenolic antioxidants, hindered amine antioxidants, phosphite antioxidants, and thiol antioxidants; and / or, The anti-hydrolysis agent is selected from at least one of carbodiimide type, isocyanate, epoxy compound, oxazoline, and acid anhydride.

10. A method for preparing the high-strength, high-toughness polyglycolic acid graft copolymer composition according to any one of claims 7 to 9, comprising the step of mixing the high-strength, high-toughness polyglycolic acid graft copolymer with a processing aid; preferably, comprising: The components, including polyglycolic acid, graft copolymer monomer, free radical initiator, and processing aid, are melt-reacted and extruded to obtain the high-strength and high-toughness polyglycolic acid graft copolymer composition.

11. The preparation method according to claim 10, characterized in that, Based on a total mass percentage of 100 wt% for all materials, the polyglycolic acid comprises 65–98.89 wt%, preferably 82–98.89 wt%; the graft copolymer comprises 1–20 wt%, preferably 1–10 wt%; the free radical initiator comprises 0.01–5 wt%, preferably 0.01–3 wt%; the processing aid comprises 0.1–10 wt%, preferably 0.1–5 wt%; and / or, The conditions for the melting reaction are: temperature of 150-280℃ and rotation speed of 50-1200 rpm; preferably, temperature of 170-250℃ and rotation speed of 100-500 rpm.

12. The application of a high-strength, high-toughness polyglycolic acid graft copolymer composition according to any one of claims 1 to 4 or according to any one of claims 7 to 9 in blown film, cast film, multilayer film, sheet, fiber, and injection molded products.

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