Preparation method of polyglycolic acid composite material as well as composite material and application thereof

Abstract

The invention discloses a preparation method of a polyglycolic acid composite material as well as the composite material and application thereof, and relates to the technical field of polymer synthesis. The preparation method of the polyglycolic acid composite material comprises the following steps: carrying out esterification reaction on a hydroxy acid ester monomer, a micromolecular initiator, a macromolecular initiator and an esterification catalyst; obtaining a pre-esterified polymer; and carrying out condensation polymerization on the pre-esterified polymer and a condensation polymerization catalyst to prepare the polyglycolic acid composite material, optionally, the polycondensation reaction is followed by a chain propagation reaction. The polyglycolic acid composite material provided by the invention can be prepared in a simple, green and low-cost manner by introducing a macromolecular initiator into a polymerization system, the overall molecular weight and melt viscosity of the polyglycolic acid composite material are greatly improved compared with those of an existing one-step polyglycolic acid preparation technology, and the application requirements in the fields of injection molding, film bags, foaming and the like can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer synthesis, and more particularly to a method for preparing a polyglycolic acid composite material, the composite material and applications thereof. Background Art

[0002] Polyglycolic acid (PGA), also known as polyglycolide or polyglycolic acid, is a fully biodegradable material that degrades completely within 1-3 months under natural conditions. PGA also exhibits excellent mechanical properties, strong barrier properties to O2 and CO2, and is non-toxic, harmless, and environmentally friendly. It has been certified as a safe biodegradable plastic material in the United States, the European Union, and Japan.

[0003] There are two routes for the preparation of polyglycolic acid. One is to obtain it by direct polycondensation of glycolic acid (or its derivatives), which is called the one-step method. Since the esterification process is an equilibrium reaction, in order to shift the reaction towards polycondensation as much as possible, it is necessary to continuously remove the small molecules generated by the reaction. However, as the polycondensation reaction proceeds, the viscosity of the system increases, and the removal of small molecules becomes increasingly difficult. Therefore, the polyglycolic acid obtained by this method has a low molecular weight, usually less than 20,000 Mw, and low melt strength during molding and processing, making it difficult to use for subsequent processing. The other method is to first polycondense glycolic acid (or its derivatives) to obtain a low molecular weight prepolymer, then heat and control the decomposition of the prepolymer to obtain two molecules of glycolic acid (or its derivatives) after removing the small molecules to form a six-membered cyclic glycolide. Then, by ring-opening polymerization of glycolide, polyglycolic acid with a molecular weight greater than 100,000 can be obtained. This is also called the two-step method. The current mainstream method for the preparation of polyglycolic acid is the two-step method. However, the two-step method is technically complex and requires high equipment. In particular, it is difficult to obtain polymerization-grade high-purity glycolide monomer, which has greatly limited the expansion of the polyglycolic acid industry and the reduction of costs.

[0004] Chinese patent CN112469761 provides a method for producing a product containing polyglycolic acid and glycolide from methyl glycolate. Also provided are a product produced by this method and a method for varying the amount of polyglycolic acid in the product by varying the amount of esterification catalyst and / or adjusting the reaction temperature. Under optimal conditions, the resulting polyglycolic acid can have a molecular weight of 90,000 to 200,000 and an intrinsic viscosity of 0.8 to 1.3 dL / g through a multi-step reaction. However, this method remains difficult to apply in applications requiring higher molecular weights and melt strengths, such as extrusion and blown film.

[0005] Chinese patent CN101616907 discloses a method for preparing glycolide from glycolic acid, and a method for preparing polyglycolic acid having a weight-average molecular weight (Mw) greater than 200,000 by ring-opening polymerization of glycolide. The two-step process for preparing polyglycolic acid is significantly more complex than the one-step process, and the polymerization process uses a large amount of high-boiling-point solvent, increasing energy consumption and placing high demands on solvent recovery.

[0006] Chinese patent CN112513133 discloses a novel polyglycolic acid (PGA) that is modified with isocyanate chain extension after polymerization, resulting in a melt strength of 5-30 cN at 230°C. However, isocyanate modification is associated with high toxicity, and the biodegradability of the resulting PGA is reduced. Furthermore, this method requires post-polymerization modification, resulting in complex process steps and demanding reaction conditions.

[0007] In summary, how to overcome the problems of low molecular weight of polyglycolic acid obtained by the one-step route and complex technology and high cost of the two-step route, and to prepare polyglycolic acid with performance that meets application requirements in a simple, green and low-cost manner is an urgent problem to be solved. Summary of the Invention

[0008] To address the problems existing in the prior art, the present invention provides a method for preparing a polyglycolic acid composite material, the composite material, and its applications. The polyglycolic acid composite material provided by the present invention can be prepared simply, environmentally friendly, and cost-effectively by introducing a macromolecular initiator into the polymerization system. Its overall molecular weight and melt viscosity are significantly improved compared to existing one-step polyglycolic acid preparation technologies, meeting the application requirements of injection molding, film bagging, foaming, and other fields.

[0009] One of the purposes of the present invention is to provide a method for preparing a polyglycolic acid composite material.

[0010] The preparation method of the polyglycolic acid composite material of the present invention comprises subjecting a hydroxy acid ester monomer, a small molecule initiator, a macromolecular initiator and an esterification catalyst to an esterification reaction to obtain a pre-esterified polymer; subjecting the pre-esterified polymer to a polycondensation reaction with a polycondensation catalyst to obtain the polyglycolic acid composite material; and optionally, performing a chain growth reaction after the polycondensation reaction.

[0011] The following solutions can be adopted:

[0012] (1) a hydroxy acid ester monomer, a small molecule initiator, and a macromolecular initiator are subjected to an esterification reaction in the presence of an esterification catalyst to obtain a pre-esterified polymer;

[0013] (2) The pre-esterified polymer undergoes a polycondensation reaction in the presence of a polycondensation catalyst to obtain the novel polyglycolic acid composite material; optionally, the polycondensation reaction is followed by a chain growth reaction.

[0014] Preferably, the chain growth reaction can be specifically carried out in the following manner:

[0015] If a higher molecular weight is desired, the polycondensation reaction product can undergo chain extension in an optimized reactor. In a reactor equipped with strong stirring, the resulting polyglycolic acid composite can be further treated to remove small molecules to increase molecular weight. Alternatively, the product can be reacted with active substances such as polyisocyanates and multifunctional epoxides to achieve chain extension and viscosity enhancement. The reactor can include at least one of a falling strip devolatilizer, a twin-screw devolatilizer, a belt-stirred reactor, a horizontal disk-and-loop reactor, or a biaxial self-cleaning reactor (such as a coaxial twin-screw extruder). The molecular weight of the polyglycolic acid composite after the chain extension reaction is higher than that before the reaction.

[0016] Preferably,

[0017] The hydroxy acid ester monomer is at least one of α-hydroxy acid ester and β-hydroxy acid ester; preferably, the hydroxy acid ester monomer is at least one of methyl glycolate and methyl lactate; and / or,

[0018] The small molecule initiator described in the present invention can be selected from a wide range. The small molecule initiator is a small molecule substance containing hydroxyl and / or amino groups with a boiling point greater than 160° C. at normal pressure; preferably, the molecular weight of the small molecule initiator is not greater than 1000 g / mol, preferably 60-300 g / mol, including but not limited to: at least one of ethylene glycol, butanediol, glycerol, serinol, leucinol, pentaerythritol, sorbitol, xylitol, amino acids, phenol, hydroquinone, resorcinol, benzyl alcohol, aniline, benzylamine, p-phenylenediamine, m-phenylenediamine, hexamethylenediamine, and dodecanediamine; and / or,

[0019] The macroinitiator is a polymer containing hydroxyl groups in the repeating unit; preferably at least one of polyvinyl alcohol and ethylene-vinyl alcohol copolymer; and / or,

[0020] The esterification catalyst is at least one of tin salts, zinc salts, titanium salts, sulfur salts, tin oxide, zinc oxide, titanium oxide, and sulfur oxide; for example, it can be stannous chloride dihydrate, stannous octoate, tetrabutyl titanate, etc.; and / or,

[0021] The polycondensation catalyst is a compound of a rare earth element, for example, a compound of cerium (Ce), dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), holmium (Ho), lanthanum (La), lutetium (Lu), neodymium (Nd), praseodymium (Pr), promethium (Pm), samarium (Sm), scandium (Sc), terbium (Tb), thulium (Tm), ytterbium (Yb), or yttrium (Y), preferably an oxide of a rare earth element or a complex of a rare earth element. The polycondensation catalyst specifically used in the present invention can be, for example, lanthanum trioxide, Ce2(CO3)3, or the like.

[0022] Preferably,

[0023] The alcoholysis degree of the polyvinyl alcohol described in the present invention can be selected in a wide range, and the alcoholysis degree of the polyvinyl alcohol is 68-99%. And / or, the polymerization degree of the polyvinyl alcohol described in the present invention can be selected in a wide range, and the polymerization degree is 100-6000, preferably 300-2000, for example, it can be 300, 500, 1000, 1500, 2000, and any value within the limited range and the interval between any two values; and / or,

[0024] The ethylene-vinyl alcohol copolymer described in the present invention can be selected from a wide range. The content of ethylene segments in the ethylene-vinyl alcohol copolymer is 0 mol% to 50 mol%, preferably 25-50 mol%, for example, 25 mol%, 35 mol%, 45 mol%, 50 mol%, and any numerical value and any interval within the limited interval. And / or, the degree of polymerization of the ethylene-vinyl alcohol copolymer is 50-6000, preferably 300-2000, for example, 300, 500, 1000, 1500, 2000, and any numerical value and any interval within the limited interval. And / or, the melt flow rate of the ethylene-vinyl alcohol copolymer described in the present invention can be selected from a wide range. The melt flow rate of the ethylene-vinyl alcohol copolymer at 190°C / 2.16kg is 0.1-50 g / 10min.

[0025] Preferably,

[0026] Based on 100 parts by weight of the hydroxy acid ester monomer:

[0027] The amount of the small molecule initiator can be selected within a wide range. The amount of the small molecule initiator is 0-10 parts by weight, preferably 0.001-1 parts by weight, and more preferably 0.05-0.5 parts by weight.

[0028] The amount of the macroinitiator can be selected within a wide range, and the amount of the macroinitiator is 0.01-10 parts by weight, preferably 0.1-5 parts by weight, and more preferably 0.5-2 parts by weight;

[0029] The amount of the esterification catalyst can be selected within a wide range. The amount of the esterification catalyst is 0.001-1 parts by weight, preferably 0.01-0.1 parts by weight, and more preferably 0.025-0.05 parts by weight.

[0030] The amount of the polycondensation catalyst can be selected within a wide range. The amount of the polycondensation catalyst is 0.001-1 part by weight, preferably 0.01-0.1 part by weight, and more preferably 0.0125-0.05 part by weight.

[0031] During the preparation of the polyglycolic acid composite material of the present invention, an antioxidant may be added in steps (1) and (2). Since the reaction temperature of step (2) is higher and the effect is more obvious, the antioxidant may be selected from a wider range. In a preferred embodiment of the present invention, the antioxidant is selected from hindered phenol antioxidants and / or phosphite antioxidants, that is, it may be hindered phenols and phosphite antioxidants and any combination thereof, including but not limited to 2,6-di-tert-butyl-p-cresol, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 2,2'-methylenebis(6-tert-butyl-4-methylphenol), hexanediol bis[β-(3,5-dibutyl-4-hydroxyphenyl)propionate], tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester (such as BASF's antioxidant Irganox 1010), N,N'-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (such as antioxidant 1024), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine (such as antioxidant 1098), β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid n-octadecyl ester (such as BASF's antioxidant Irganox 1076), at least one of 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, triphenyl phosphite, tris(4-nonphenyl) phosphite, diphenyl isooctyl phosphite, diphenyl isodecyl phosphite, diphenyl di(2-ethylhexyl) phosphite, phenyl diisodecyl phosphite, tris(2-ethylhexyl) phosphite, triisodecyl phosphite, tridodecyl phosphite, pentaerythritol diisodecyl diphosphite, tris[2,4-di-tert-butylphenyl] phosphite (such as antioxidant 168), bis(2,4-dicumylphenyl) pentaerythritol diphosphite (such as antioxidant 686) and bis(2,4-di-tert-butylphenyl) propionic acid] pentaerythritol diphosphite (such as antioxidant 626).

[0032] The amount of the antioxidant used in the present invention can be selected within a wide range. In a preferred embodiment of the present invention, based on 100 parts by weight of the hydroxy acid ester monomer, the amount of the antioxidant used is 0-2 parts by weight, preferably 0.01-1 part by weight.

[0033] Preferably,

[0034] The conditions of the esterification reaction can be selected within a wide range. In a preferred embodiment of the present invention, the reaction temperature of the esterification reaction is 110-200° C., and / or the reaction time is 10 minutes to 10 hours; and / or,

[0035] The conditions of the polycondensation reaction can be selected in a wide range. In a preferred embodiment of the present invention, the reaction temperature of the polycondensation reaction is 200-250° C., and / or the reaction time is 2-100 hours, preferably 2-100 hours; and / or the vacuum degree is 10-5000 Pa; and / or,

[0036] The chain extension reaction conditions can be selected within a wide range. In a preferred embodiment of the present invention, the chain extension reaction temperature is 200-250°C, and / or the reaction time is 2-100 hours, and / or the vacuum degree is 10-5000Pa.

[0037] The second object of the present invention is to provide a method for preparing a polyglycolic acid composite material and the polyglycolic acid composite material prepared.

[0038] The polyglycolic acid composite material prepared by the preparation method of the present invention includes a polyester graft copolymer and a polyester homopolymer, and its molecular weight distribution is multimodal, including a polyester graft copolymer with a higher molecular weight and a polyester homopolymer with a lower molecular weight; wherein the molecular weight of the polyester graft copolymer is higher than that of the polyester homopolymer; the structural formula of the polyester graft copolymer is:

[0039]

[0040] wherein x, y1, y2 and z each independently represent a degree of polymerization, PM represents a polyester chain and the degree of polymerization of the polyester chain is p, wherein x and p each independently represent a positive integer, and y1, y2 and z each independently represent an integer of zero or greater than zero.

[0041] Preferably,

[0042] The polyester graft copolymer and the polyester homopolymer are simultaneously polymerized in situ; and / or,

[0043] The sum of x, y1, y2 and z is not less than 50, preferably 50-6000, more preferably 200-2500; and / or,

[0044] The p is not less than 40, preferably 44-2000; and / or,

[0045] The ratio of z to the sum of x, y1, y2 and z is 0%-50%; and / or,

[0046] The ratio of y1 to the sum of x, y1 and y2 is 0%-32%.

[0047] In the present invention, the sum of x+y1+y2+z is the degree of polymerization of polyvinyl alcohol and ethylene-vinyl alcohol copolymer, which can be calculated based on the number average molecular weight of the raw materials polyvinyl alcohol and ethylene-vinyl alcohol copolymer; and the ratio of z to the sum of x+y1+y2+z can be calculated based on the integrated area of the corresponding characteristic peaks of the nuclear magnetic hydrogen spectrum; the ratio of x+y2 to the sum of x+y1+y2 (i.e., 100% - the ratio of y1 to the sum of x+y1+y2) is the alcoholysis degree of the ethylene-vinyl alcohol copolymer, which is a known parameter of the raw materials before leaving the factory and can also be detected by various detection methods known in the art such as nuclear magnetic resonance and near infrared.

[0048] In the present invention, if the structure of the starting ethylene-vinyl alcohol copolymer macroinitiator is known, then p = (number average molecular weight of the high molecular weight portion PGA - number average molecular weight of the macroinitiator) / (number of vinyl alcohol structures in one ethylene-vinyl alcohol copolymer molecule * molecular weight of the PGA repeating unit). If the high molecular weight PGA of the graft copolymer structure described in the present invention is obtained directly, it can be fully hydrolyzed first, the initiator can be collected, and its structure analyzed. Calculations show that the p values in the polymers of the present invention are all greater than 40. According to the above technical solution, the GPC curve of the polyglycolic acid composite material of the present invention has the characteristics of a multimodal molecular weight distribution, which contains two polyglycolic acid components with different chemical structures: the higher molecular weight is the polyglycolic acid graft copolymer, and the lower molecular weight is the polyglycolic acid homopolymer.

[0049] Preferably,

[0050] The polyester homopolymer and the polyester chain are independently derived from hydroxy acid ester monomers; preferably, the polyester homopolymer and the polyester chain are independently derived from at least one of α-hydroxy acid ester and β-hydroxy acid ester; more preferably, the polyester homopolymer and the polyester chain are independently derived from at least one of methyl glycolate and methyl lactate.

[0051] Preferably,

[0052] Based on 100 parts by weight of the polyester chains in the polyester graft copolymer and the polyester homopolymer (the polyester chains in the polyester graft copolymer and the polyester homopolymer include all polyester homopolymers and PM polyester chains in the polyester graft copolymer), the copolymer main chain derived from the macroinitiator in the polyester graft copolymer is 0.01-10 parts by weight, preferably 0.1-5 parts by weight; and / or

[0053] Based on the total weight of the polyester graft copolymer and the polyester homopolymer as 100%, the content of the polyester graft copolymer is 0.1wt%-90.0wt%, preferably 1.0wt%-80.0wt%; the content of the polyester homopolymer is 10wt%-99.9wt%, preferably 20.0wt%-99.0wt%.

[0054] Preferably,

[0055] The total weight average molecular weight of the polyglycolic acid composite material is 100,000-1.5 million g / mol, preferably 120,000-1 million g / mol; and / or,

[0056] The polyglycolic acid composite material has an overall molecular weight polydispersity index of 1.5-20.0, preferably 2-15; and / or,

[0057] The number of peaks in the molecular weight distribution of the polyglycolic acid composite material is at least 2; and / or,

[0058] The weight average molecular weight of the polyester graft copolymer is 500,000-10 million g / mol, preferably 800,000-6 million g / mol; and / or,

[0059] The weight average molecular weight of the polyester homopolymer is 5,000-150,000 g / mol, preferably 10,000-100,000 g / mol.

[0060] Preferably,

[0061] The polyester graft copolymer is a polyglycolic acid graft copolymer, and the structural formula of the polyglycolic acid graft copolymer is:

[0062]

[0063] In formula (I), x, y1, y2, z and p each independently represent a degree of polymerization, wherein x and p each independently represent a positive integer, and y1, y2 and z each independently represent an integer of zero or greater.

[0064] Preferably,

[0065] The sum of x, y1, y2 and z is not less than 50, preferably 50-6000, more preferably 200-2500; and / or,

[0066] The p is not less than 40, preferably 44-2000; and / or,

[0067] The ratio of z to the sum of x, y1, y2 and z is 0%-50%; and / or,

[0068] The ratio of y1 to the sum of x, y1 and y2 is 0%-32%.

[0069] Preferably,

[0070] When the main chain of the polyglycolic acid graft copolymer is an ethylene-vinyl alcohol copolymer segment, the ratio of z to the sum of x+y1+y2+z is 1%-50%, preferably 20%-45%; the ratio of y1 to the sum of x+y1+y2 is 0.1%-6%; and / or,

[0071] When the main chain of the polyglycolic acid graft copolymer is a polyvinyl alcohol segment, z is 0, and the proportion of y1 to the sum of x+y1+y2 is 1%-32%.

[0072] Preferably,

[0073] The polyester homopolymer is a polyglycolic acid homopolymer, and the structural formula of the polyglycolic acid homopolymer is:

[0074]

[0075] Where n1, ..., ni are the degrees of polymerization; i is the number of atoms directly connected to R. , i≥1; Mi is an imino group, a secondary amino group or an ether bond; R is at least one of hydrogen, an aliphatic group or an aromatic group; when i>1, M1, M2, ..., Mi are different or the same, and n1, n2, ..., ni are different or the same;

[0076] Preferably, i is any integer from 1 to 20, preferably any integer from 2 to 6, for example, 2, 3, 4, 5, or 6; n is the degree of polymerization. The selection range of n on each branch is relatively wide, and it is difficult to calculate the respective values. The sum of all n values can be calculated by dividing the number average molecular weight of the lower molecular weight peak in the GPC results by the molecular weight of the PGA repeating unit. After calculation, the sum of all n values in the polyglycolic acid homopolymer obtained in the present invention is not less than 66; R is an alkane group or an aromatic hydrocarbon group having a molecular weight of 14 to 1000 g / mol.

[0077] The average degree of polymerization (x, y1, y2, z, p and n) obtained by calculation in the present invention needs to be rounded off during calculation.

[0078] Preferably,

[0079] The content of each polymer segment in the novel polyglycolic acid composite material of the present invention can be selected in a wide range. For 100 parts by weight ( Present in polyglycolic acid graft copolymer and polyglycolic acid homopolymer middle),

[0080] The polyglycolic acid composite material 0.01-10 parts by weight, preferably 0.1-5 parts by weight;

[0081] The polyglycolic acid composite material The content of the active ingredient is 0.001-10 parts by weight, preferably 0.01-1 part by weight.

[0082] The weight content of each of the above segments can be measured using methods known in the art, or calculated based on the amount of material added during the preparation process.

[0083] Preferably,

[0084] The total weight average molecular weight of the polyglycolic acid composite material of the present invention can be selected in a wide range. The total weight average molecular weight of the polyglycolic acid composite material is 100,000-1.5 million g / mol, preferably 120,000-1 million g / mol, for example, 120,000 g / mol, 200,000 g / mol, 300,000 g / mol, 500,000 g / mol, 800,000 g / mol, 1 million g / mol, and any other numerical value or interval within the specified range; and / or,

[0085] The overall molecular weight distribution index of the polyglycolic acid composite material of the present invention has a wide selection range, and the overall molecular weight polydispersity index of the polyglycolic acid composite material is 1.5-20.0, preferably 2-15; and / or,

[0086] The polyglycolic acid composite material of the present invention has a wide range of selection for the number of molecular weight distribution peaks. The number of molecular weight distribution peaks can be detected by gel permeation chromatography (GPC). The molecular weight distribution peak can be detected by finding the peak at the weight average molecular weight (M w ) is greater than 5000 g / mol (i.e. lg(M w ) is greater than 3.7) and the first-order derivative is zero and the second-order derivative is less than zero. The number of molecular weight distribution peaks of the polyglycolic acid composite material is at least 2, for example, including but not limited to 2, 3; and the peak molecular weight M p Greater than 500,000 (i.e., the peak value in the GPC curve lg (M w ) greater than 5.7) and the peak molecular weight M pLess than 500,000 (i.e., the peak value in the GPC curve lg (M w ) is less than 5.7) is at least 1; and / or,

[0087] The weight average molecular weight of the polyglycolic acid graft copolymer of the present invention has a wide range of selection. The weight average molecular weight of the polyglycolic acid graft copolymer is 500,000-10 million g / mol, preferably 800,000-6 million g / mol, for example, 800,000 g / mol, 1.2 million g / mol, 2 million g / mol, 3 million g / mol, 4 million g / mol, 5 million g / mol, 6 million g / mol, and any other numerical value or interval within the specified range; and / or,

[0088] The weight average molecular weight of the polyglycolic acid homopolymer of the present invention can be selected in a wide range. The weight average molecular weight of the polyglycolic acid homopolymer is 5,000-150,000 g / mol, preferably 10,000-100,000 g / mol, for example, 10,000 g / mol, 20,000 g / mol, 30,000 g / mol, 50,000 g / mol, 80,000 g / mol, 100,000 g / mol, and any other value or interval within the specified range.

[0089] Preferably,

[0090] The content of the polyglycolic acid graft copolymer and the polyglycolic acid homopolymer in the polyglycolic acid composite material of the present invention can be selected in a wide range. Based on the total weight of the polyglycolic acid composite material as 100%, the content of the polyglycolic acid graft copolymer is 0.1wt%-90.0wt%, preferably 1.0wt%-80.0wt%; the content of the polyglycolic acid homopolymer is 10wt%-99.9wt%, preferably 20.0wt%-99.0wt%. The proportion of the polyglycolic acid graft copolymer in the whole can be calculated from the ratio of the peak area of the portion with a molecular weight greater than 500,000 in the GPC curve to the total peak area; and / or,

[0091] The total weight average molecular weight of the polyglycolic acid composite material, the overall molecular weight distribution index of the polyglycolic acid composite material, the number of molecular weight distribution peaks of the polyglycolic acid composite material, the weight average molecular weight of the polyglycolic acid graft copolymer, the molecular weight polydispersity index of the polyglycolic acid graft copolymer, the molecular weight polydispersity index of the polyglycolic acid homopolymer, the mass fraction of the polyglycolic acid graft copolymer, the mass fraction of the polyglycolic acid homopolymer, and other parameters can be detected by gel permeation chromatography (GPC). The specific detection method can adopt conventional detection parameters in the field. For example, the following method can be used, but not limited to: the test instrument is a PL-GPC50 gel permeation chromatograph from Angilent, USA, and the processing software is GPC offline. During the test, the mobile phase is hexafluoroisopropanol containing 5 mmol / L sodium trifluoroacetate, the flow rate is 1 mL / min, the column temperature is 40°C, the injection volume is 100 μL, the standard sample is PMMA, and the sample concentration is 1 mg / mL. According to the analytical methods known to those skilled in the art, the specific values of the above parameters are obtained;

[0092] The melt flow rate (MFR) of the polyglycolic acid composite material at 230°C / 2.16kg is 0.5-50g / 10min, preferably 1-20g / 10min, for example, it can be 1g / 10min, 1.5g / 10min, 2.0g / 10min, 3.0g / 10min, 4.0g / 10min, 5.0g / 10min, 6.0g / 10min, 7.0g / 10min, 8.0g / 10min, 9.0g / 10min, 10.0g / 10min, 12.0g / 10min, 15.0g / 10min, 20.0g / 10min, and any numerical value and any interval within the limited range.

[0093] The melt flow rate can be measured using methods known to those skilled in the art, such as, but not limited to, the following method: The test is conducted on a CEAST MF20 melt flow tester (Instron, USA). The test temperature is 230°C, the load is 2.16 kg, and the preheating time is 4 minutes.

[0094] The third object of the present invention is to provide a polyglycolic acid composite material for use in tableware, lunch boxes, film bags, temporary blocking balls, foaming materials, and barrier materials.

[0095] Compared with the prior art, the present invention has the following advantages:

[0096] The polyglycolic acid composite material in the present invention can be obtained by directly polymerizing hydroxy acid ester monomers without going through the glycolide step, with a short process route, low technical difficulty and low equipment requirements; the raw materials (hydroxy acid ester monomers) of the present invention are more primary, easy to obtain and lower in cost, so the cost of the polymer composite material finally obtained is also lower; and the polyglycolic acid composite material has a higher overall molecular weight, a lower melt flow rate and higher toughness, which can meet the application requirements in the fields of film bags, injection molding, foaming, etc., overcomes the problems of the existing technology, and has extremely high promotion and application value.

[0097] The inventors of the present invention believe that the above advantages are due to the following reasons:

[0098] (1) The present invention uses polyhydroxylated polyvinyl alcohol or ethylene-vinyl alcohol copolymer as an initiator to initiate the ring-opening polymerization of the monomers, thereby increasing the hydroxyl content and improving the reaction efficiency. Furthermore, since most of the excess hydroxyl groups are located on the same main chain, the problem of molecular weight reduction caused by excessive initiator in conventional preparation methods is avoided, and an ultra-high molecular weight polyglycolic acid that is difficult to directly obtain using conventional preparation methods can be obtained.

[0099] (2) The presence of the polyglycolic acid homopolymer in the present invention improves the processability of the obtained product, while obtaining a polymer with a wide molecular weight distribution, thereby making it have better mechanical properties.

[0100] (3) The polyglycolic acid composite material of the present invention comprises at least two polyglycolic acids of different molecular weights. The high molecular weight portion provides higher melt strength and good mechanical properties, while the low molecular weight portion provides higher toughness and sufficient processing performance. Therefore, the two components of the present invention have a synergistic effect, and obtain comprehensive properties that are difficult for a single-component polyglycolic acid to have.

[0101] (4) Compared with the prior art thickening process using chain extenders such as isocyanates for post-chain extension modification, the polyglycolic acid composite material of the present invention is a multimodal molecular weight distribution polyglycolic acid material obtained by in situ polymerization. The raw materials do not contain highly toxic substances such as isocyanates, and thus are more environmentally friendly, efficient, and low-cost. DETAILED DESCRIPTION

[0102] The present invention will be described in detail below with reference to specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art to the present invention based on the contents of the present invention still fall within the scope of protection of the present invention.

[0103] The endpoints of the ranges and any values 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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0104] The raw materials used in the examples and comparative examples of the present invention are all commercially available products, and their specific information is as follows:

[0105] Methyl glycolate was purchased from AVIC New Materials Co., Ltd. with a purity of 99%.

[0106] Stannous chloride dihydrate, stannous octoate, Ce2(CO3)3, 1,4-butanediol (BDO, molecular weight 90 g / mol, boiling point about 228 °C at normal pressure), glycerol (molecular weight 92 g / mol, boiling point about 290 °C at normal pressure), pentaerythritol (molecular weight 136 g / mol, boiling point about 380 °C at normal pressure), tetra-n-butyl titanate, and lanthanum trioxide were all purchased from Sinopharm Chemical Reagent Co., Ltd., and all were reagent grade.

[0107] The chain extender is produced by BASF, Germany, with the brand ADR4468.

[0108] Antioxidant 1010 is CP grade.

[0109] The white oil is a CP grade product produced by Shanghai Sinopharm Chemical Testing Co., Ltd.

[0110] Polyvinyl alcohol (PVA) was purchased from Chongqing Chuanwei Chemical Co., Ltd. of Sinopec Group with a brand name of 0388, a degree of polymerization of about 300, a degree of alcoholysis of 88%, and a number average molecular weight of about 13,200.

[0111] Ethylene-vinyl alcohol copolymer (EVOH) was purchased from Kuraray Co., Ltd., Japan, with the brand name EVAL TM H171B has an ethylene segment content of 38 mol% and a melt flow rate of 1.7 g / 10 min at 190°C / 2.16 kg. GPC testing indicates a number average molecular weight of approximately 18,000 g / mol and a degree of polymerization of approximately 480. EVOH is typically prepared by alcoholysis of vinyl acetate units in ethylene-vinyl acetate copolymers, with the degree of alcoholysis generally exceeding 99%. Therefore, the number of vinyl acetate units per EVOH molecule used in the present invention (i.e., the value of y1 in formula (I)) is an integer between 0 and 4. For ease of calculation, y1 is assumed to be 1 in the present invention.

[0112] The present invention performs performance measurement according to the following method:

[0113] Melt flow rate measurement: Tests were conducted on a CEAST MF20 melt flow tester (Instron, USA). The test temperature was 230°C, the load was 2.16 kg, and the preheating time was 4 minutes.

[0114] Gel Permeation Chromatography (GPC): Testing was performed on a PL-GPC50 gel permeation chromatograph (Angilent, USA), using GPC offline software. The mobile phase consisted of hexafluoroisopropanol containing 5 mmol / L sodium trifluoroacetate, at a flow rate of 1 mL / min, a column temperature of 40°C, and an injection volume of 100 μL. The standard sample was PMMA, with a sample concentration of 1 mg / mL.

[0115] [Example 1]

[0116] In a 5L esterification reactor, 1000g of methyl glycolate, 1g of BDO, 10g of PVA, and 0.5g of stannous chloride dihydrate were added. The mixture was heated to 140°C under atmospheric pressure and stirred continuously to thoroughly mix the materials. The temperature was then raised from 140°C to 180°C over 1 hour and allowed to react at this temperature for 3 hours. The contents of the esterification reactor were transferred to a 5L polycondensation reactor set at 210°C, and 0.25g of Ce2(CO3)3 was added. The mixture was stirred continuously under a vacuum of 100 Pa for 6 hours to produce a polyglycolic acid composite material.

[0117] The GPC results obtained according to the above gel permeation chromatography test method showed that it had two molecular weight distribution peaks, and the overall M w The molecular weight distribution is 149,000 g / mol, and the molecular weight distribution is 8.4, among which the M w is 23900 g / mol, accounting for about 43%, and the high molecular weight part of M w The melt flow rate of the product of this embodiment is 875300 g / mol, accounting for about 57%. The result obtained by the melt flow rate determination method described above is 9.1 g / 10 min. According to the structural formula shown in formula (I), in the high molecular weight portion of the product of this embodiment, x+y2 is about 264, y1 is about 36, z is 0, and p is about 56.

[0118] [Example 2]

[0119] In a 5L esterification reactor, 1000g of methyl glycolate, 2g of BDO, 20g of PVA, and 0.5g of stannous chloride dihydrate were added. The mixture was heated to 140°C under atmospheric pressure and stirred continuously to thoroughly mix the materials. The temperature was then raised from 140°C to 200°C over 1 hour, and the reaction was maintained at this temperature for 3 hours. The contents of the esterification reactor were transferred to a 5L polycondensation reactor set at 220°C, and 0.25g of Ce2(CO3)3 was added. The reaction was continued with stirring under a vacuum of 100 Pa for 6 hours to produce a polyglycolic acid composite material.

[0120] The GPC results obtained according to the above gel permeation chromatography test method showed that it had two molecular weight distribution peaks, and the overall M w The molecular weight distribution is 188,000 g / mol, and the molecular weight distribution is 10.7, among which the M w is 18900 g / mol, accounting for about 34%, and the high molecular weight part of M w The melt flow rate of the product of this embodiment is 681900 g / mol, accounting for about 66%. The result obtained by the melt flow rate determination method described above is 6.7 g / 10 min. According to the structural formula shown in formula (I), in the high molecular weight portion of the product of this embodiment, x+y2 is about 264, y1 is about 36, z is 0, and p is about 44.

[0121] [Example 3]

[0122] In a 5L esterification reactor, 1000g of methyl glycolate, 1g of BDO, 10g of EVOH, and 0.5g of stannous chloride dihydrate were added. The mixture was heated to 140°C under atmospheric pressure and stirred continuously to thoroughly mix the materials. The temperature of the system was then raised from 140°C to 180°C over 1 hour and allowed to react at this temperature for 3 hours. The contents of the esterification reactor were transferred to a 5L polycondensation reactor set at 210°C, and 0.25g of Ce2(CO3)3 was added. The reaction was stirred continuously under a vacuum of 100 Pa for 8 hours to produce a polyglycolic acid composite material.

[0123] The GPC results obtained according to the above gel permeation chromatography test method showed that it had two molecular weight distribution peaks, and the overall M w The molecular weight distribution is 193,000 g / mol, and the molecular weight distribution is 9.4, among which the M w is 28300 g / mol, accounting for about 44%, and the high molecular weight part of M w The melt flow rate of the product of this embodiment is 1378900 g / mol, accounting for about 56%. The result obtained by the melt flow rate determination method described above is 4.3 g / 10 min. According to the structural formula shown in formula (I), in the high molecular weight portion of the product of this embodiment, x+y2 is about 297, y1 is 1, z is 182, and p is about 79.

[0124] [Example 4]

[0125] In a 5L esterification reactor, 1000g of methyl glycolate, 2g of BDO, 20g of EVOH, and 0.5g of stannous chloride dihydrate were added. The mixture was heated to 140°C under atmospheric pressure and stirred continuously to thoroughly mix the materials. The temperature of the system was then raised from 140°C to 200°C over 1 hour and allowed to react at this temperature for 3 hours. The contents of the esterification reactor were transferred to a 5L polycondensation reactor set at 220°C, and 0.25g of Ce2(CO3)3 was added. The reaction was continued with stirring under a vacuum of 100 Pa for 8 hours to produce a polyglycolic acid composite material.

[0126] The GPC results obtained according to the above gel permeation chromatography test method showed that it had two molecular weight distribution peaks, and the overall M w The molecular weight distribution is 7.2, of which the M w is 21900 g / mol, accounting for about 38%, and the high molecular weight part of M w The melt flow rate of the product of this embodiment is 1,086,700 g / mol, accounting for about 62%. The melt flow rate obtained by the above method is 2.7 g / 10 min. According to the structural formula shown in formula (I), in the high molecular weight portion of the product of this embodiment, x+y2 is about 297, y1 is 1, z is 182, and p is about 62.

[0127] [Example 5]

[0128] In a 5L esterification reactor, 1000g of methyl glycolate, 0.5g of BDO, 5g of EVOH, and 0.5g of stannous chloride dihydrate were added. The mixture was heated to 140°C under normal pressure and stirred continuously to thoroughly mix the materials. The temperature of the system was then raised from 140°C to 200°C over 1 hour and allowed to react at this temperature for 3 hours. The contents of the esterification reactor were transferred to a 5L polycondensation reactor set at 230°C, and 0.25g of Ce2(CO3)3 was added. The reaction was continued with stirring under a vacuum of 100 Pa for 10 hours to obtain a polyglycolic acid composite material.

[0129] The GPC results obtained according to the above gel permeation chromatography test method showed that it had two molecular weight distribution peaks, and the overall M w The molecular weight distribution is 166,000 g / mol, and the molecular weight distribution is 9.2, among which the molecular weight of the low molecular weight part is M w is 37800 g / mol, accounting for about 61%, and the high molecular weight part of M wThe melt flow rate of the product of this embodiment is 1664500 g / mol, accounting for about 39%. The melt flow rate obtained by the above method is 11.7 g / 10 min. According to the structural formula shown in formula (I), in the high molecular weight portion of the product of this embodiment, x+y2 is about 297, y1 is 1, z is 182, and p is about 96.

[0130] [Example 6]

[0131] In a 5L esterification reactor, 1000g of methyl glycolate, 1g of BDO, 10g of PVA, and 0.25g of stannous chloride dihydrate were added. The mixture was heated to 140°C under atmospheric pressure and stirred continuously to thoroughly mix the materials. The temperature was then raised from 140°C to 200°C over 1 hour and allowed to react at this temperature for 3 hours. The contents of the esterification reactor were transferred to a 5L polycondensation reactor set at 220°C, to which 0.125g of Ce2(CO3)3 was added. The reaction was continued with stirring under a vacuum of 100 Pa for 15 hours to produce a polyglycolic acid composite material.

[0132] The GPC results obtained according to the above gel permeation chromatography test method showed that it had two molecular weight distribution peaks, and the overall M w The molecular weight distribution is 156,000 g / mol, and the molecular weight distribution is 12.8, among which the molecular weight of the low molecular weight part is M w is 20900 g / mol, accounting for about 41%, and the high molecular weight part of M w The melt flow rate of the product of this embodiment is 873,300 g / mol, accounting for about 59%. The melt flow rate obtained by the above method is 8.4 g / 10 min. According to the structural formula shown in formula (I), in the high molecular weight portion of the product of this embodiment, x+y2 is about 264, y1 is about 36, z is 0, and p is about 56.

[0133] [Example 7]

[0134] In a 5L esterification reactor, 1000g of methyl glycolate, 1g of glycerol, 10g of PVA, and 0.5g of stannous chloride dihydrate were added. The mixture was heated to 140°C under normal pressure and stirred continuously to thoroughly mix the materials. The system temperature was then raised from 140°C to 180°C within 1 hour and allowed to react at this temperature for 3 hours. The contents of the esterification reactor were transferred to a 5L polycondensation reactor set at 210°C, and 0.25g of Ce2(CO3)3 was added. The mixture was stirred continuously under a vacuum of 100 Pa for 6 hours to obtain a polyglycolic acid composite material.

[0135] The GPC results obtained according to the above gel permeation chromatography test method showed that it had two molecular weight distribution peaks, and the overall M wThe molecular weight distribution is 145,000 g / mol, and the molecular weight distribution is 9.8, among which the molecular weight of the low molecular weight part is M w is 21800 g / mol, accounting for about 48%, and the high molecular weight part of M w The melt flow rate of the product of this embodiment is 817000 g / mol, accounting for about 52%. The result obtained by the melt flow rate determination method described above is 12.3 g / 10 min. According to the structural formula shown in formula (I), it can be calculated that in the high molecular weight portion of the product of this embodiment, x+y2 is about 264, y1 is about 36, z is 0, and p is about 52.

[0136] [Example 8]

[0137] In a 5L esterification reactor, 1000g of methyl glycolate, 1g of BDO, 10g of PVA, and 0.5g of stannous octoate were added. The mixture was heated to 140°C under atmospheric pressure and stirred continuously to thoroughly mix the materials. The temperature was then raised from 140°C to 180°C over 1 hour and allowed to react at this temperature for 3 hours. The contents of the esterification reactor were transferred to a 5L polycondensation reactor set at 210°C, and 0.25g of Ce2(CO3)3 was added. The mixture was stirred continuously under a vacuum of 100 Pa for 6 hours to produce a polyglycolic acid composite material.

[0138] The GPC results obtained according to the above gel permeation chromatography test method showed that it had two molecular weight distribution peaks, and the overall M w The molecular weight distribution is 167,000 g / mol, and the molecular weight distribution is 8.3, among which the molecular weight of the low molecular weight part is M w is 24200 g / mol, accounting for about 42%, and the high molecular weight part of M w The melt flow rate of the product of this embodiment is 948600 g / mol, accounting for about 58%. The result obtained by the melt flow rate determination method described above is 5.8 g / 10 min. According to the structural formula shown in formula (I), it can be calculated that in the high molecular weight portion of the product of this embodiment, x+y2 is about 264, y1 is about 36, z is 0, and p is about 61.

[0139] [Example 9]

[0140] In a 5L esterification reactor, 1000g of methyl glycolate, 1g of pentaerythritol, 10g of PVA, and 0.5g of tetra-n-butyl titanate were added. The mixture was heated to 140°C under atmospheric pressure and stirred continuously to thoroughly mix the materials. The temperature was then raised from 140°C to 180°C over 1 hour and allowed to react at this temperature for 3 hours. The contents of the esterification reactor were transferred to a 5L polycondensation reactor set at 210°C, and 0.25g of lanthanum trioxide was added. The mixture was stirred continuously under a vacuum of 100 Pa for 6 hours to produce a polyglycolic acid composite material.

[0141] The GPC results obtained according to the above gel permeation chromatography test method showed that it had two molecular weight distribution peaks, and the overall M w The molecular weight distribution is 143,000 g / mol, and the molecular weight distribution is 10.1, among which the molecular weight of the low molecular weight part is M w is 20900 g / mol, accounting for about 47%, and the high molecular weight part of M w The melt flow rate of the product of this embodiment is 808900 g / mol, accounting for about 53%. The result obtained by the melt flow rate determination method described above is 11.4 g / 10 min. According to the structural formula shown in formula (I), in the high molecular weight portion of the product of this embodiment, x+y2 is about 264, y1 is about 36, z is 0, and p is about 52.

[0142] [Example 10]

[0143] The polyglycolic acid composite material prepared in Example 6, ADR 4468, antioxidant 1010, and white oil were fully premixed in a mass ratio of 1000:3:5:5. The blend was prepared using PolyLabHAAKE from Thermo Fisher Scientific, USA. TM A Rheomex OS PTW16 co-rotating twin-screw extruder (screw diameter 16 mm, L / D = 40) was used for extrusion granulation. The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and was not heated. A calibrated feeder fed the blend into the twin screws at a rate of 2000 g / hr. The temperatures in sections 2-11 of the extruder were 220°C, 220°C, 230°C, 230°C, 240°C, 250°C, 250°C, 240°C, 230°C, and 220°C, respectively. The screw speed was set at 200 rpm, with a torque range of 27-33 Nm. The extruder was equipped with a circular die with a diameter of 3 mm. The extruded strips were air-cooled and then cut into cylindrical pellets approximately 3 mm in length using a pelletizer. The pellets were collected and packaged for later use. The melt index was determined to be 1.5 g / 10 min according to the melt flow rate determination method.

[0144] [Comparative Example 1]

[0145] In a 5L esterification reactor, 1000g of methyl glycolate, 1g of BDO, and 0.5g of stannous chloride dihydrate were added. The mixture was heated to 140°C under atmospheric pressure and stirred continuously to thoroughly mix the materials. The temperature was then raised from 140°C to 200°C over 1 hour, and the reaction was maintained at this temperature for 3 hours. The contents of the esterification reactor were transferred to a 5L polycondensation reactor set at 210°C, and 0.25g of Ce2(CO3)3 was added. The reaction was continued with stirring under a vacuum of 100 Pa for 6 hours to produce the polyglycolic acid product.

[0146] The GPC results obtained according to the above gel permeation chromatography test method showed that it had only one molecular weight distribution peak, M w The melt flow rate was 36800 g / mol and the molecular weight distribution was 1.9. The melt flow rate was >100 g / 10 min according to the above method.

[0147] A total of 11 pellets from Examples 1-10 and Comparative Example 1 were used in an injection molding feasibility test on an M55 injection molding machine from German company BOY. The injection molding process was as follows: fully dried materials were added to the injection molding machine, melted, injected, and cooled to obtain the target part. The temperatures of sections 1 to 3 and the injection port of the injection molding machine were 200°C, 230°C, 240°C, and 240°C, respectively, and the mold temperature was 60°C. The results showed that during the backward feeding process of the injection screw, the melt viscosity of the pellets from Comparative Example 1 was too low, resulting in a large amount of melt flowing out of the nozzle, making it difficult to complete the entire injection molding process. However, the 10 pellets from Examples 1-10 were able to complete the injection molding process well and obtain the target part.

Claims

1. A method for preparing a polyglycolic acid composite material, comprising subjecting a hydroxy acid ester monomer, a small molecule initiator, a macromolecular initiator, and an esterification catalyst to an esterification reaction to obtain a pre-esterified polymer; subjecting the pre-esterified polymer to a polycondensation reaction with a polycondensation catalyst to obtain the polyglycolic acid composite material; and optionally, performing a chain extension reaction after the polycondensation reaction.

2. The preparation method according to claim 1, wherein: The hydroxy acid ester monomer is at least one of α-hydroxy acid ester and β-hydroxy acid ester; preferably, the hydroxy acid ester monomer is at least one of methyl glycolate and methyl lactate; and / or, The small molecule initiator is a small molecule substance containing hydroxyl groups and / or amino groups with a boiling point greater than 160° C. at normal pressure; preferably, the molecular weight of the small molecule initiator is not greater than 1000 g / mol, preferably 60-300 g / mol; and / or, The macroinitiator is a polymer containing hydroxyl groups in the repeating unit; preferably at least one of polyvinyl alcohol and ethylene-vinyl alcohol copolymer; and / or, The esterification catalyst is at least one of tin salts, zinc salts, titanium salts, sulfur salts, tin oxide, zinc oxide, titanium oxide, and sulfur oxide; and / or The polycondensation catalyst is a compound of a rare earth element, preferably an oxide of a rare earth element or a complex of a rare earth element.

3. The preparation method according to claim 2, wherein: The polyvinyl alcohol has an alcoholysis degree of 68-99%, and / or a polymerization degree of 100-6000, preferably 300-2000; and / or, The content of ethylene segments in the ethylene-vinyl alcohol copolymer is 0 mol% to 50 mol%, and / or the degree of polymerization of the ethylene-vinyl alcohol copolymer is 50-6000, preferably 300-2000, and / or the melt flow rate of the ethylene-vinyl alcohol copolymer at 190°C / 2.16kg is 0.1-50 g / 10min.

4. The preparation method according to claim 1, wherein: Based on 100 parts by weight of the hydroxy acid ester monomer: The amount of the small molecule initiator is 0-10 parts by weight, preferably 0.001-1 parts by weight; and / or, The amount of the macroinitiator is 0.01-10 parts by weight, preferably 0.1-5 parts by weight; and / or, The esterification catalyst is used in an amount of 0.001-1 parts by weight, preferably 0.01-0.1 parts by weight; and / or, The polycondensation catalyst is used in an amount of 0.001-1 part by weight, preferably 0.01-0.1 part by weight.

5. The preparation method according to claim 1, wherein: The reaction temperature of the esterification reaction is 110-200° C., and / or the reaction time is 10 minutes to 10 hours; and / or, The reaction temperature of the polycondensation reaction is 200-250° C.; and / or, the reaction time is 2-200 hours, preferably 2-100 hours; and / or, the vacuum degree is 10-5000 Pa; and / or, The reaction temperature of the chain extension reaction is 200-250° C., and / or the reaction time is 2-100 hours, and / or the vacuum degree is 10-5000 Pa.

6. A polyglycolic acid composite material prepared by the preparation method according to any one of claims 1 to 5; The polyglycolic acid composite material comprises a polyester homopolymer and a polyester graft copolymer; wherein, The molecular weight of the polyester homopolymer is lower than that of the polyester graft copolymer.

7. The polyglycolic acid composite material according to claim 6, characterized in that: The polyester graft copolymer and the polyester homopolymer are simultaneously polymerized in situ.

8. The polyglycolic acid composite material according to claim 6, wherein: The polyester chains in the polyester homopolymer and the polyester graft copolymer are independently derived from hydroxy acid ester monomers; preferably, the polyester homopolymer and the polyester chains are independently derived from at least one of α-hydroxy acid ester and β-hydroxy acid ester; more preferably, the polyester homopolymer and the polyester chains are independently derived from at least one of methyl glycolate and methyl lactate.

9. The polyglycolic acid composite material according to claim 6, wherein: Based on 100 parts by weight of the polyester chain in the polyester graft copolymer and the polyester homopolymer, the copolymer main chain derived from the macroinitiator in the polyester graft copolymer is 0.01-10 parts by weight, preferably 0.1-5 parts by weight; and / or Based on the total weight of the polyester graft copolymer and the polyester homopolymer as 100%, the content of the polyester graft copolymer is 0.1wt%-90.0wt%, preferably 1.0wt%-80.0wt%; the content of the polyester homopolymer is 10wt%-99.9wt%, preferably 20.0wt%-99.0wt%.

10. The polyglycolic acid composite material according to any one of claims 6 to 9, characterized in that: The weight average molecular weight of the polyester graft copolymer is 500,000-10 million g / mol, preferably 800,000-6 million g / mol; and / or, The weight average molecular weight of the polyester homopolymer is 5,000-150,000 g / mol, preferably 10,000-100,000 g / mol.

11. The polyglycolic acid composite material according to claim 6, characterized in that: The polyester graft copolymer is a polyglycolic acid graft copolymer; and the polyester homopolymer is a polyglycolic acid homopolymer.

12. The polyglycolic acid composite material according to claim 11, characterized in that: The total weight average molecular weight of the polyglycolic acid composite material is 100,000-1.5 million g / mol, preferably 120,000-1 million g / mol; and / or, The polyglycolic acid composite material has an overall molecular weight polydispersity index of 1.5-20.0, preferably 2-15; and / or, The polyglycolic acid composite material has at least 2 molecular weight distribution peaks; and / or, The weight average molecular weight of the polyglycolic acid graft copolymer is 500,000-10 million g / mol, preferably 800,000-6 million g / mol; and / or, The weight average molecular weight of the polyglycolic acid homopolymer is 5000-150,000 g / mol, preferably 10,000-100,000 g / mol.

13. The polyglycolic acid composite material according to claim 11, characterized in that: Based on the total weight of the polyglycolic acid composite material as 100%, the content of the polyglycolic acid graft copolymer is 0.1wt%-90.0wt%, preferably 1.0wt%-80.0wt%; the content of the polyglycolic acid homopolymer is 10wt%-99.9wt%, preferably 20.0wt%-99.0wt%; and / or, The polyglycolic acid composite material has a melt flow rate of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, at 230° C. / 2.16 kg.

14. Use of the polyglycolic acid composite material prepared by the preparation method according to any one of claims 1 to 5 or the polyglycolic acid composite material according to any one of claims 6 to 13 in tableware, lunch boxes, film bags, temporary blocking balls, foam materials, and barrier materials.

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