Low-density polyglycolic acid-based porous modified material as well as preparation method and application thereof

Abstract

The invention provides a low-density polyglycolic acid-based porous modified material as well as a preparation method and application thereof. With the total weight of the low-density polyglycolic acid-based porous modified material as 100 parts by weight, the modified material comprises the following components: 92-99.5 parts by weight of a polyglycolic acid-based polymer; preferably 94 to 98 parts by weight; 0.5-8 parts by weight of a foaming modification aid; preferably 1-5 parts by weight; 0-5 parts by weight of a thermoplastic compatilizer; preferably, 0.5-4 parts by weight; and 0-5 parts by weight of other additives. And preferably 0.5-4 parts by weight. The preparation method comprises the following steps: extruding and foaming the components including the polyglycolic acid-based polymer, the foaming modification additive, the thermoplastic compatilizer and other additives to obtain the low-density polyglycolic acid-based polymer modified material. The obtained modified material is lighter in weight and lower in cost.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and more particularly to a low-density polyglycolic acid-based porous modified material and a preparation method and application thereof. Background Art

[0002] Polyglycollide (PGA), also known as polyglycolic acid or polyglycolic acid, is a polymer material with excellent biocompatibility and unique biodegradability. Its high crystallinity imparts high strength, enabling its application in applications requiring high strength, such as surgical drug delivery, orthopedic fixation, and tissue repair. However, its high crystallinity also results in a high density, limiting its expanded use cases.

[0003] Methods for reducing material density include foaming modification of the material, adding low-density materials for blending, etc. Among them, there are foam materials prepared for low-density modification of PGA, including a preparation method using supercritical carbon dioxide for twin-screw extrusion. However, this method has problems such as expensive equipment and harsh production conditions, and its industrial application is relatively complicated.

[0004] The existing technology has the problems that the density of polyglycolide-based polymer materials is high, it is difficult to reduce the density, and commonly used foaming agents are difficult to apply. Therefore, it is necessary to develop a low-density PGA modified material and a simple preparation method to solve the corresponding technical problems. Summary of the Invention

[0005] In order to solve the technical problems existing in the prior art, the present invention provides a low-density polyglycolic acid-based porous modified material and a preparation method and application thereof.

[0006] The polyglycolide-based polymer materials in the existing technology have high density, difficulty in reducing the density, and difficulty in applying commonly used foaming agents. The porous polyglycolic acid material is prepared using supercritical carbon dioxide, has low yield, and is not stable enough.

[0007] The present invention prepares a low-density polyglycolic acid-based modified material by adding a foaming modification agent to a polyglycolic acid-based raw material, overcoming the defects of commonly used foaming agents, reducing the density of the PGA material, making it lighter and less costly. The material can be used in surgical drug carriers, orthopedic fixation, tissue repair materials, and foamed disposable products.

[0008] One of the purposes of the present invention is to provide a low-density polyglycolic acid-based porous modified material, which comprises the following components, based on the total weight of the low-density polyglycolic acid-based porous modified material being 100 parts by weight:

[0009]

[0010] In a preferred embodiment of the present invention,

[0011] The polyglycolic acid-based polymer is at least one of a linear polyglycolide homopolymer, a polyglycolide graft copolymer, and a branched polyglycolide homopolymer;

[0012] The foaming modification aid is at least one of foaming microsphere modification aid powder and foaming microsphere modification aid masterbatch;

[0013] The molecular structure of the thermoplastic compatibilizer comprises a hard segment polyglycolide polymer at one end and a soft segment at the other end, wherein the soft segment is a hydroxyl-terminated polymer containing an ester group, an ether group or a butene group; the soft segment is preferably a hydroxyl-terminated polyester, a hydroxyl-terminated polyether or a hydroxyl-terminated conjugated olefin polymer, more preferably polytetrahydrofuran, polycaprolactone or hydroxyl-terminated polybutadiene; the thermoplastic compatibilizer can be prepared by referring to the prior art, for example, by referring to Chinese invention patent CN105175676A (invention title: "Polylactic acid-based polyurethane elastomer material for medical infusion sets and preparation method thereof");

[0014] The other additives are at least one of an antioxidant, white oil, and an anti-hydrolysis agent;

[0015] The polyglycolic acid-based polymer has a melt flow rate of 0.1 to 60 g / 10 min at 230° C. / 2.16 kg;

[0016] The overall weight average molecular weight of the polyglycolic acid-based polymer is 100,000 to 1,000,000 g / mol, preferably 120,000 to 200,000 g / mol.

[0017] In a preferred embodiment of the present invention,

[0018] The weight average molecular weight of the linear polyglycolide homopolymer is greater than 100,000 g / mol;

[0019] The main chain of the polyglycolide graft copolymer is ethylene-vinyl alcohol copolymer, and the side chain includes polyglycolic acid. The structural formula is shown in formula (I):

[0020]

[0021] Where x, y, z, and p are all integers, and the sum of x+y+z is not less than 100;

[0022] The structural formula of the branched polyglycolide homopolymer is shown in formula (II):

[0023]

[0024] Among them, M1, M2, ..., M iare the same or different and are independently selected from imino, nitro or ether bonds; R is a hydrogen atom or an alkane or aromatic hydrocarbon group with a molecular weight of 14 to 1000 g / mol; n1, n2, ..., n i The sum is not less than 40; and / or, i is 1 to 20, preferably 4 to 8.

[0025] In a preferred embodiment of the present invention,

[0026] In formula (I), the sum of x+y+z is 100 to 6000, preferably 300 to 2000, for example, 300, 500, 1000, 1500, 2000, and any two values or any interval between any two values;

[0027] In formula (I), the ratio of x to the sum of x+y+z is 1% to 32%, for example, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 32%, and any two values or any interval between two values;

[0028] According to the present invention, the sum of x+y+z can be calculated by the number average molecular weight of the raw material polyvinyl alcohol, the ratio of x to the sum of x+y+z is the alcoholysis degree of polyvinyl alcohol, and the ratio of y to z can be calculated by the integrated area of nuclear magnetic hydrogen spectrum.

[0029] According to the present invention, the alcoholysis degree of polyvinyl alcohol is a known parameter of the raw material before leaving the factory, and can also be detected by various detection methods in the art such as nuclear magnetic resonance and near infrared.

[0030] According to the present invention, if the structure of the starting macroinitiator is known, then p = (number average molecular weight of the high molecular weight portion PGA - number average molecular weight of the macroinitiator (polyvinyl alcohol)) / (y*PGA repeating unit molecular weight). 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, its structure can be analyzed, and then tested in the above manner. According to the embodiments of the present invention later, it is calculated that the p values in the obtained polymers are all greater than 10. According to the present invention, the selectable range of the p value is relatively wide. In a preferred embodiment of the present invention, p is greater than 10, and more preferably, p is greater than 50.

[0031] According to the present invention, the average degree of polymerization (x, y, z, p) obtained by calculation needs to be rounded off during calculation.

[0032] According to the present invention, the selection range is relatively wide. In a preferred embodiment of the present invention, n1, n2, ..., n i The sum is not less than 50. According to the present invention, n1, n2, ..., n iThe sum of the values can be calculated by dividing the molecular weight of the lower molecular weight peak in the GPC results by the molecular weight of the PGA repeating unit. According to the embodiments of the present invention, it is calculated that n1, n2, ..., n i The sum of the values is greater than 50.

[0033] According to the present invention, the selectable range of i value is relatively wide. In a preferred embodiment of the present invention, the range of i is 1 to 20, and the preferred range of i is 4 to 8, for example, it can be 4, 5, 6, 7, or 8.

[0034] In a preferred embodiment of the present invention,

[0035] The self-made multimodal PGA particles of the present invention comprise the above polyglycolide graft copolymer and branched polyglycolide homopolymer;

[0036] Polyglycolide segments can be obtained by polymerization The monomer, polyvinyl alcohol, and an optional small molecule co-initiator are subjected to melt polymerization in the presence of a catalyst, and then cooled to obtain a mixture of a polyglycolide graft copolymer and a branched polyglycolide homopolymer; preferably, the raw materials also include an antioxidant.

[0037] In a preferred embodiment of the present invention,

[0038] The monomer is selected from at least one of methyl glycolate, glycolic acid and glycolide, preferably glycolide;

[0039] The alcoholysis degree of the polyvinyl alcohol is 68-99%;

[0040] The degree of polymerization of the polyvinyl alcohol is 100 to 6000, preferably 300 to 2000;

[0041] The small molecule co-initiator is a small molecule substance having a boiling point greater than 160° C. and containing at least one functional group selected from a plurality of hydroxyl groups and an amino group. Preferably, the small molecule co-initiator has a molecular weight of less than 1000 g / mol, preferably 60 to 300 g / mol. The small molecule co-initiator includes, but is 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.

[0042] The catalyst is a salt compound corresponding to at least one of Group IIA-VA metal elements and transition metal elements or an organic guanidine catalyst; preferably, the catalyst is a salt compound corresponding to at least one of Sn, Bi, Mg, Al, Ca, Fe, Mn, Ti and Zn, more preferably a Sn salt;

[0043] The antioxidant is a hindered phenol antioxidant and / or a phosphite antioxidant, for example, 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]pentylene glycol. Tetraethanol esters (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), 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, monophenyl 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 (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).

[0044] The total amount of the antioxidant used is 0 to 2 parts by mass, preferably 0.01 to 1 part, relative to 100 parts by mass of the monomer.

[0045] In a preferred embodiment of the present invention,

[0046] The amount of the polyvinyl alcohol is 0.001 to 10 parts by mass, preferably 0.01 to 1 part, relative to 100 parts by mass of the monomer;

[0047] The amount of the small molecule co-initiator is 0.001 to 10 parts by mass, more preferably 0.01 to 1 part, relative to 100 parts by mass of the monomer;

[0048] The amount of the catalyst used is 0.005 to 0.01 parts by mass, preferably 0.01 to 0.2 parts by mass, relative to 100 parts by mass of the monomer;

[0049] The conditions for the melt polymerization reaction include: a temperature of 160 to 250° C., preferably 200 to 240° C.; a reaction time of 0.5 to 60 minutes, preferably 1 to 10 minutes;

[0050] The melt polymerization reaction is carried out in a melt mixing device; preferably, the melt mixing device is a series combination of one or more of a kettle reactor, a tubular reactor, an internal mixer, a Farrel continuous mixer, a Banbury mixer, a single screw extruder, a multi-screw extruder and a reciprocating single screw extruder, more preferably an internal mixer or a twin-screw extruder; further preferably,

[0051] The melt polymerization reaction is carried out in a continuous twin-screw extruder. Preferably, the processing temperature is 180-250°C, preferably 210-240°C, the screw speed is 5-300rpm, preferably 40-150rpm, and the aspect ratio is 30-80, preferably 40-70.

[0052] In a more preferred embodiment of the present invention,

[0053] The melt polymerization reaction is carried out in at least two twin-screw extruders connected in series. Preferably, the processing conditions of each twin-screw extruder in series include:

[0054] The processing temperature is 180-250°C, preferably 210-240°C;

[0055] The screw speed is 5 to 300 rpm, preferably 40 to 150 rpm;

[0056] The aspect ratio is 30-80, preferably 40-70.

[0057] In a preferred embodiment of the present invention,

[0058] The particle size of the foamed microsphere modification auxiliary agent powder is 10 to 40 μm, preferably 15 to 25 μm;

[0059] The initial foaming temperature of the foaming microsphere modification auxiliary agent powder is 165-220°C, preferably 190-215°C;

[0060] The foaming peak temperature of the foaming microsphere modification auxiliary agent powder is 210-290°C, preferably 235-245°C;

[0061] The minimum foaming density of the foaming microsphere modified auxiliary powder is less than 0.06g / cm 3 , the minimum foaming density refers to the minimum density that the sphere of the foaming agent can reach under the foaming condition;

[0062] The initial foaming temperature of the foaming microsphere modified auxiliary agent masterbatch is 125-210°C, preferably 185-205°C;

[0063] The foaming peak temperature of the foaming microsphere modified auxiliary agent masterbatch is 190 to 250°C, preferably 220 to 240°C.

[0064] In a preferred embodiment of the present invention,

[0065] The shell of the foamed microsphere modified auxiliary agent powder is thermoplastic plastic, and the interior is wrapped with liquid alkane; preferably,

[0066] The thermoplastic plastic is at least one of polybutylene adipate, butylene terephthalate, polylactic acid, polybutylene succinate, polystyrene, and polymethyl methacrylate;

[0067] The thickness of the shell is 8 to 20 μm, more preferably 13 to 14 μm;

[0068] The diameter of the liquid alkane contained inside is 1 to 6 μm, more preferably 2 to 4 μm;

[0069] The foaming microsphere modification auxiliary agent powder is, for example, DU308 foaming microsphere modification auxiliary agent powder produced by Cresray Technology (Shanghai) Co., Ltd.

[0070] In a preferred embodiment of the present invention,

[0071] The foaming microsphere modification auxiliary agent masterbatch is prepared by blending the foaming microsphere modification auxiliary agent powder with ethylene-vinyl acetate copolymer; preferably,

[0072] The vinyl acetate content of the ethylene-vinyl acetate copolymer is 10 to 28%, preferably 15 to 25%;

[0073] The mass of the ethylene-vinyl acetate copolymer is 40-60% of the total mass of the foaming microsphere modification auxiliary agent masterbatch, preferably 45-55%;

[0074] The foaming microsphere modification auxiliary agent masterbatch is, for example, EV330 foaming modification auxiliary agent masterbatch produced by Crestron Technologies (Shanghai) Co., Ltd.

[0075] In a preferred embodiment of the present invention,

[0076] The density of the low-density polyglycolic acid-based porous modified material is 0.7 to 1.5 g / cm 3 ;

[0077] The foaming ratio of the low-density polyglycolic acid-based porous modified material is 1.1 to 2.3, preferably 1.2 to 1.9.

[0078] Foaming ratio = density of raw material polyglycolic acid-based polymer / density of low-density polyglycolic acid-based porous modified material product.

[0079] A second object of the present invention is to provide a method for preparing a low-density polyglycolic acid-based porous modified material, comprising:

[0080] The components including polyglycolic acid-based polymer, foaming modification aid, thermoplastic compatibilizer, and other additives are extruded and foamed to obtain the low-density polyglycolic acid-based polymer modified material; preferably, the extrusion foaming is carried out in a single-screw extruder or a twin-screw extruder.

[0081] In a preferred embodiment of the present invention,

[0082] The temperature of extrusion foaming is 210-250°C, preferably 220-245°C;

[0083] The rotation speed of the single-screw extruder or the twin-screw extruder is 10 to 120 rpm, preferably 15 to 60 rpm.

[0084] The third object of the present invention is to provide an application of the above-mentioned low-density polyglycolic acid-based porous modified material in surgical drug carriers, orthopedic fixation, tissue repair materials, and foamed disposable products.

[0085] Compared with the prior art, the present invention has the following beneficial effects:

[0086] The present invention has developed a suitable process when using screw foaming extrusion. When the screw speed is too fast, the shear rate is too high, which will cause the foaming agent to break in the screw and lose the foaming effect. Therefore, the speed of the screw extruder should be set below 120 rpm, preferably below 60 rpm.

[0087] The polyglycolic acid-based polymer modified material prepared by the present invention significantly reduces the density of the polyglycolic acid-based polymer by adding a foaming modification agent for screw foaming extrusion. At the same time, the foaming agent does not cause degradation during PGA processing, broadens the application scenarios of PGA, and provides more possible application markets. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 Density curves of the PGA modified materials of Examples 1 to 3 and Examples 8 to 13 under different formulations and processing techniques;

[0089] Figure 2 This is an electron microscope photograph of the PGA modified material prepared in Example 1;

[0090] Figure 3 This is an electron microscope photograph of the PGA modified material prepared in Example 2;

[0091] Figure 4 This is an electron microscope photograph of the PGA modified material prepared in Example 3;

[0092] Figure 5 This is an electron microscope photograph of the PGA modified material prepared in Example 10;

[0093] Figure 6 This is an electron microscope photograph of the PGA modified material prepared in Example 11;

[0094] Figure 7 This is an electron microscope photograph of the PGA modified material prepared in Example 12;

[0095] Figure 8 This is an electron microscope photograph of the PGA modified material prepared in Example 13;

[0096] Figure 9 This is a photo of the appearance of the PGA modified material prepared in Comparative Example 3;

[0097] Figure 10 This is a photo of the appearance and morphology of the PGA modified material prepared in Example 13. DETAILED DESCRIPTION

[0098] The present invention will be described in detail below with reference to specific drawings and embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some 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.

[0099] The multimodal PGA particles and compatibilizer used in the examples were homemade, and the other raw materials were conventional commercially available raw materials;

[0100] Main commercially available raw materials:

[0101] Polyglycolic acid-based polymer (PGA) was produced by Shenzhen Boli Biotechnology Co., Ltd. (brand PGA-03) and was oven-warmed at 45°C for 2 h before use. PGA-03 is a linear polyglycolide homopolymer with a weight-average molecular weight of approximately 150,000 g / mol.

[0102] The foaming modifier powder is produced by Crestry Technology (Shanghai) Co., Ltd., with the brand name DU308;

[0103] The foaming modification additive masterbatch is produced by Crestron Technologies (Shanghai) Co., Ltd., with the brand name EV330;

[0104] Table 1

[0105]

[0106] Glycolide: purity ≥99.5%, purchased from Shenzhen Boli Biomaterial Co., Ltd.;

[0107] Ethylene-vinyl alcohol copolymer: alcoholysis degree 95%, purchased from Kuraray Co., Ltd., Japan;

[0108] Stannous octoate: purity AR, purchased from Sinopharm Group Co., Ltd.;

[0109] The homemade multimodal PGA particles were returned to temperature in an oven at 45 °C for 2 h before use;

[0110] The preparation method of multimodal PGA particles is:

[0111] The raw materials were mixed uniformly in a mass ratio of 100:0.1:0.005:0.045:0.5:0.3 for glycolide (GA), stannous octoate, ethylene-vinyl alcohol copolymer (EVOH), 1,4-butanediol, antioxidant 1010, and antioxidant 626. The mixture was then fed via a feeder into a Labtech parallel, co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40) for reaction extrusion, cooling, and pelletization. The feed rate was 3 kg / h and the screw speed was 150 rpm. The extruder had 11 sections from the feed port to the die, numbered 1-11. Section 1 served only for feeding and did not heat the extruder. The temperatures of extruder sections 2-11 were 160°C, 200°C, 220°C, 220°C, 220°C, 220°C, 220°C, 230°C, 235°C, and 240°C, respectively. The material residence time in the extruder was approximately 8 minutes on average. The extruder was then pelletized to obtain homemade multimodal PGA particles. The homemade multimodal PGA particles contained glycolic acid graft polymers and polyglycolic acid branched homopolymers.

[0112] The structural formula of polyglycolic acid graft polymer is:

[0113]

[0114] Among them, x, y, z, and p are all integers, and the sum of x+yy+z is approximately 200.

[0115] The structural formula of polyglycolic acid branched homopolymer is:

[0116]

[0117] M1, M2, and M3 are all ether bonds, and the overall weight-average molecular weight of the self-made multimodal PGA particles is 530,000.

[0118] Preparation of thermoplastic compatibilizer: prepared with reference to Chinese invention patent CN105175676A (invention title: “Polylactic acid-based polyurethane elastomer material for medical infusion sets and preparation method thereof”);

[0119] The specific preparation method is as follows: Under nitrogen protection, 80g of polyglycolide diol with a molecular weight of 1000 (Wuhan Haishan Technology Co., Ltd.) and 50ml of tetrahydrofuran are added to a three-necked flask. Then, 8g of toluene diisocyanate and dibutyltin dilaurate are added, and 1g of butanediol is added. The reaction temperature is 65°C and the reaction time is 3 hours. After cooling, the thermoplastic compatibilizer is obtained.

[0120] The soft segment of the prepared thermoplastic compatibilizer is polytetrahydrofuran, and the hard segment is polyglycolide.

[0121] The test instruments and test conditions used in the examples are as follows:

[0122] Melt flow rate (MFR) was determined in accordance with ISO 1133 using an Instron CEAST MF20 melt indexer. The test was performed at a barrel temperature of 230°C, a load of 2.16 kg, a die diameter of 2.095 mm, and a length of 8 mm. The preheating time was 4 minutes. Samples were automatically cut at set intervals, and the average of five cuts was calculated. The results were expressed in grams per 10 minutes (g / 10 min).

[0123] Thermal performance analysis (DSC): The test was carried out on a Discovery series differential scanning calorimeter (DSC) produced by TA Instruments. The processing software was TA Instruments Trios version 3.1.5. The DSC instrument was equipped with a TA Refrigerated Cooling System 90 mechanical refrigeration accessory. The test atmosphere was nitrogen at 50 mL / min, and the sample amount required for the test was 5 to 10 mg. The test procedure was as follows: first stabilize the temperature at -50°C, then increase the temperature to 250°C at 10°C / min and keep the temperature constant for 2 minutes to remove the thermal history, then cool it to -50°C at 10° / min, and then increase the temperature to 250°C at 10°C / min. Record the cooling process and the second heating process to study the thermal properties of the sample. Through DSC testing, the glass transition (T g ), melting temperature (T m ), melting enthalpy (ΔH) and other information.

[0124] Particle density test method: The test is conducted using an SD-200L electronic hydrometer manufactured by Alfa Mirage, Japan. The test method utilizes the Archimedes principle and complies with JIS K6530 for rubber and JIS K7112 for plastics. The test method is as follows: First, measure the particle's weight in air (m1), then measure its weight in a liquid (water, ethanol, etc.) (m2). The particle density is calculated using the following formula:

[0125]

[0126] The parts in the following examples and comparative examples are all parts by weight.

[0127] [Example 1]

[0128] To 96 parts of polyglycolic acid-based polymer PGA-03, one part of foaming modifier powder, two parts of thermoplastic compatibilizer, and one part of white oil additive were added. The mixture was mixed in a high-speed mixer for 10 minutes and then extruded into pellets using a PolyLab single-screw extruder manufactured by Thermo Fisher Scientific Inc. (USA). The extruder had four sections, numbered 1 to 4, from the feed port to the die. Section 1 served only for feeding and was not heated. The temperatures of sections 2 to 4 were 235°C, 240°C, and 230°C, respectively, and the screw speed was set at 25 rpm. The extruder was equipped with a circular die with a diameter of 3 mm. After extrusion, the extruded strips were air-cooled and then cut into cylindrical pellets with a set diameter of approximately 3 mm using a pelletizer. This yielded a low-density polyglycolic acid-based porous modified material. The extruder was then dried in a vacuum oven at 60°C for 4 hours before packaging for later use.

[0129] [Example 2]

[0130] The difference from Example 1 is that the dosage of components is different; specifically:

[0131] Add 1.5 parts of foaming modifier powder, 2 parts of thermoplastic compatibilizer, and 1 part of white oil additive to 95.5 parts of polyglycolic acid-based polymer PGA-03;

[0132] Except for the above differences, other conditions in Example 2 are the same as those in Example 1. A low-density polyglycolic acid-based porous modified material is obtained, which is then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0133] [Example 3]

[0134] The difference from Example 1 is that the dosage of components is different; specifically:

[0135] Add 2 parts of foaming modifier powder, 2 parts of thermoplastic compatibilizer, and 1 part of white oil additive to 95 parts of polyglycolic acid-based polymer PGA-03;

[0136] Except for the above differences, other conditions in Example 3 are the same as those in Example 1. A low-density polyglycolic acid-based porous modified material is obtained, which is then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0137] [Example 4]

[0138] The difference from Example 1 is that the dosage of components is different; specifically:

[0139] Add 0.5 parts of foaming modifier powder, 0.5 parts of thermoplastic compatibilizer, and 1 part of white oil additive to 98 parts of polyglycolic acid-based polymer PGA-03;

[0140] Except for the above differences, other conditions in Example 4 were the same as those in Example 1. A low-density polyglycolic acid-based porous modified material was obtained, which was then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0141] [Example 5]

[0142] The difference from Example 1 is that the dosage of components is different; specifically:

[0143] Add 2 parts of foaming modifier powder, 4 parts of thermoplastic compatibilizer, and 2 parts of white oil additive to 92 parts of polyglycolic acid-based polymer PGA-03;

[0144] Except for the above differences, other conditions in Example 5 are the same as those in Example 1. A low-density polyglycolic acid-based porous modified material is obtained, which is then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0145] [Example 6]

[0146] The difference from Example 1 is that the dosage of components is different; specifically:

[0147] Add 1 part of foaming modifier powder, 4 parts of thermoplastic compatibilizer, 1 part of white oil additive, and 2 parts of anti-hydrolysis agent to 92 parts of polyglycolic acid-based polymer PGA-03;

[0148] Except for the above differences, other conditions in Example 6 are the same as those in Example 1. A low-density polyglycolic acid-based porous modified material is obtained, which is then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0149] [Example 7]

[0150] The difference from Example 1 is that the dosage of components is different; specifically:

[0151] Add 6 parts of foaming modifier powder, 1 part of thermoplastic compatibilizer, and 1 part of white oil additive to 92 parts of polyglycolic acid-based polymer PGA-03;

[0152] Except for the above differences, other conditions in Example 7 are the same as those in Example 1. A low-density polyglycolic acid-based porous modified material is obtained, which is then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0153] [Example 8]

[0154] The difference from Example 1 is that the components and amounts are different; specifically:

[0155] Polyglycolic acid-based polymer was used (homemade multimodal PGA);

[0156] To 96 parts of polyglycolic acid-based polymer (self-made multimodal PGA), add 1 part of DU308 foaming modification additive powder, 2 parts of thermoplastic compatibilizer, and 1 part of white oil additive;

[0157] Except for the above differences, other conditions in Example 8 are the same as those in Example 1. A low-density polyglycolic acid-based porous modified material is obtained, which is then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0158] [Example 9]

[0159] The difference from Example 1 is that the components and amounts are different; specifically:

[0160] Polyglycolic acid-based polymer was used (homemade multimodal PGA);

[0161] 2 parts of DU308 foaming modifier powder, 2 parts of thermoplastic compatibilizer, and 1 part of white oil additive were added to 95 parts of polyglycolic acid-based polymer (self-made multimodal PGA);

[0162] Except for the above differences, other conditions in Example 9 are the same as those in Example 1. A low-density polyglycolic acid-based porous modified material is obtained, which is then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0163] [Example 10]

[0164] To 96 parts of polyglycolic acid-based polymer PGA-03, one part foaming modifier masterbatch EV330, two parts of thermoplastic compatibilizer, and one part of white oil additive were added and mixed in a high-speed mixer for 10 minutes. The mixture was then extruded into pellets using a Eurolab 16 co-rotating twin-screw extruder (screw diameter 16 mm, aspect ratio L / D = 40) manufactured by Thermo Fisher Scientific Inc. (USA). 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. The temperatures in sections 2-11 were 225°C, 230°C, 230°C, 235°C, 240°C, 240°C, 240°C, 240°C, and 235°C, respectively. The screw speed was set at 50 rpm. During stable operation, the torque was 60% of its maximum value. The extruder is equipped with a circular die with a diameter of 3 mm. After the specimen is extruded from the die and air-cooled, it is cut into cylindrical particles with a set diameter of about 3 mm using a pelletizer to obtain a low-density polyglycolic acid-based polymer modified material. The material is then dried in a vacuum drying oven at 60°C for 4 hours and packaged for use.

[0165] [Example 11]

[0166] The difference from Example 10 is that the dosage of components is different; specifically:

[0167] Add 2 parts of foaming modification additive masterbatch EV330, 2 parts of thermoplastic compatibilizer, and 1 part of white oil additive to 95 parts of polyglycolic acid-based polymer PGA-03;

[0168] Except for the above differences, other conditions in Example 11 are the same as those in Example 10, and a low-density polyglycolic acid-based porous modified material is obtained. The material is then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0169] [Example 12]

[0170] The difference from Example 10 is that the dosage of components is different; specifically:

[0171] Add 3 parts of foaming modification additive masterbatch EV330, 2 parts of thermoplastic compatibilizer, and 1 part of white oil additive to 94 parts of polyglycolic acid-based polymer PGA-03;

[0172] Except for the above differences, other conditions of Example 12 are the same as those of Example 10, and a low-density polyglycolic acid-based porous modified material is obtained, which is then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0173] [Example 13]

[0174] The difference from Example 10 is that the dosage of components is different; specifically:

[0175] Add 5 parts of foaming modification additive masterbatch EV330, 2 parts of thermoplastic compatibilizer, and 1 part of white oil additive to 92 parts of polyglycolic acid-based polymer PGA-03;

[0176] Except for the above differences, other conditions of Example 13 are the same as those of Example 10, and a low-density polyglycolic acid-based porous modified material is obtained, which is then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0177] Density test of low-density polyglycolic acid-based polymer modified materials:

[0178] The low-density polyglycolic acid-based porous modified materials obtained in Examples 1 to 13, as well as the raw material polyglycolic acid-based polymer PGA-03 and the homemade multimodal PGA were subjected to density tests according to the above method. The obtained density data are listed in Table 2.

[0179] Table 2 Density of each particle obtained by the drainage method

[0180]

[0181] As can be seen from Table 2, with the addition of the foaming modification additive, the density of the PGA polymers prepared in Examples 1 to 13 is reduced to a certain extent. Due to the differences in processing conditions, additive types, and additive content, the density and foaming ratio of the final PGA polymer will vary, but the density is significantly reduced.

[0182] Thermal performance test of low-density polyglycolic acid-based polymer modified materials:

[0183] Differential scanning calorimetry (DSC) was performed on the four low-density polyglycolic acid-based polymer modified materials of Examples 6 to 9 to obtain the melting temperatures (T m ), glass transition (T g ), enthalpy change (ΔH), and other information, the values of which are listed in Table 2.

[0184] Table 3 Thermal performance parameters of Examples 10 to 13 and PGA-03 obtained by DSC test

[0185]

[0186] As shown in Table 3, the thermal properties of the low-density polyglycolic acid polymer modified materials prepared in Examples 10 to 13 are not significantly different from those of the raw material PGA-03 before modification, and reducing the density has no significant effect on the thermal parameters of the materials, such as Tg, Tm, and ΔH.

[0187] Melt index determination of low-density polyglycolic acid-based polymer modified materials:

[0188] The low-density polyglycolic acid-based porous modified materials obtained in Examples 1 to 3 and 8 to 13, as well as the raw material polyglycolic acid-based polymer PGA-03 and the homemade multimodal PGA were subjected to melt index measurement using an Instron CEAST MF20 melt indexer. The results are shown in Table 4.

[0189] Table 4 Melt index of various materials under 250℃ and 5kg conditions

[0190] Sample name Melt flow rate / g / 10min Example 1 38.52 Example 2 26.74 Example 3 21.38 Example 8 0.30 Example 9 0.32 Example 10 40.21 Example 11 37.70 Example 12 24.99 Example 13 17.78 PGA-03 48.27 Multimodal PGA 0.26

[0191] Table 4 shows that the flow properties of PGA polymer foamed and modified materials were tested at 230°C and 2.16 kg. The addition of a foaming agent decreased the melt flow rate (MFR), and the higher the additive content, the lower the MFR. However, the MFR of multimodal PGA itself is relatively low, and the addition of a foaming agent did not significantly change the MFR.

[0192] Scanning electron microscopy characterization of low-density polyglycolic acid-based polymer modified materials:

[0193] The three low-density polyglycolic acid-based polymer modified materials of Examples 1 to 3 with different densities were characterized by scanning electron microscopy to study their microscopic morphologies.

[0194] pass Figures 2 to 8 It can be found that with the addition of the foaming modifier, obvious holes appeared in the material, with a size of about 30 to 60 μm. This proves that the foaming modifier creates holes through the foaming of the material, thereby effectively reducing the density of the PGA material.

[0195] [Comparative Example 1]

[0196] The differences from Example 10 are: different components and amounts; different screw speeds; specifically:

[0197] To 96 parts of polyglycolic acid-based polymer PGA-03, add 1 part of foaming modification additive masterbatch EV330, 2 parts of thermoplastic compatibilizer, and 1 part of white oil additive; the screw speed is 150 rpm;

[0198] Except for the above differences, other conditions of Comparative Example 1 were the same as those of Example 10 to obtain a polyglycolic acid-based modified material, which was then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0199] [Comparative Example 2]

[0200] The differences from Comparative Example 1 are: different components and dosages; different screw speeds; specifically:

[0201] Add 2 parts of foaming modification additive masterbatch EV330, 2 parts of thermoplastic compatibilizer, and 1 part of white oil additive to 95 parts of polyglycolic acid-based polymer PGA-03; the screw speed is 150 rpm;

[0202] Except for the above differences, other conditions of Comparative Example 2 were the same as those of Comparative Example 1 to obtain a polyglycolic acid-based modified material, which was then dried in a vacuum drying oven at 60° C. for 4 hours and packaged for later use.

[0203] The density of the samples was tested, and the density of Comparative Example 1 was about 1.58 g / cm 3 , the density of comparative example 2 is about 1.57g / cm 3 Since the screw speed in Comparative Examples 1 to 2 is 150 rpm, the speed is too fast and the shear rate is too high, resulting in the foaming aid rupturing in the screw and losing the foaming effect.

[0204] Figures 9-10 The appearance morphology photos of the PGA modified materials prepared in Comparative Example 3 and Example 13 are respectively shown. It can be seen that the surface of the product obtained in Comparative Example is rough and the uniformity is poor, while the surface of the product obtained in Example 9 is smooth and the uniformity is good.

[0205] [Comparative Example 3]

[0206] The difference from Comparative Example 1 is that the components and dosages are different; specifically:

[0207] Add 2 parts of traditional inorganic foaming agent sodium bicarbonate (NaHCO3) and 1 part of white oil additive to 97 parts of polyglycolic acid-based polymer PGA-03;

[0208] Except for the above differences, the other conditions of Comparative Example 3 are the same as those of Comparative Example 1. During the experiment, it was found that the PGA product was obviously black in color, confirming that the decomposition product of NaHCO3 did not achieve a foaming effect, but instead caused the polymer to decompose in the twin-screw extruder, and the use of inorganic foaming aids could not achieve the foaming effect.

[0209] [Comparative Example 4]

[0210] Critical carbon dioxide was used for twin-screw foaming at a speed of 150 rpm. The foamed material prepared had poor uniformity of foam cells and a low foaming ratio of about 1.09, which was significantly different from the effect of using foaming additives.

[0211] The polyglycolic acid-based polymer modified materials prepared in Examples 1 to 13 significantly reduce the density of the polyglycolic acid-based polymer by adding a foaming modification agent for screw foaming extrusion. At the same time, the foaming agent does not cause degradation during PGA processing, broadens the application scenarios of PGA, and provides more possible application markets.

Claims

1. A low-density polyglycolic acid-based porous modified material, comprising the following components, based on 100 parts by weight of the total weight of the low-density polyglycolic acid-based porous modified material:

2. The low-density polyglycolic acid-based porous modified material according to claim 1, wherein: The polyglycolic acid-based polymer is at least one of a linear polyglycolide homopolymer, a polyglycolide graft copolymer, and a branched polyglycolide homopolymer; and / or, The foaming modification aid is at least one of foaming microsphere modification aid powder and foaming microsphere modification aid masterbatch; and / or, The molecular structure of the thermoplastic compatibilizer comprises a hard segment polyglycolide polymer at one end and a soft segment at the other end, wherein the soft segment is a hydroxyl-terminated polymer containing an ester group, an ether group or a butene group; the soft segment is preferably a hydroxyl-terminated polyester, a hydroxyl-terminated polyether or a hydroxyl-terminated conjugated olefin polymer, more preferably polytetrahydrofuran, polycaprolactone or hydroxyl-terminated polybutadiene; and / or, The other additives are at least one of an antioxidant, white oil, and an anti-hydrolysis agent; and / or, The polyglycolic acid-based polymer has a melt flow rate of 0.1 to 60 g / 10 min at 230° C. / 2.16 kg; and / or The overall weight average molecular weight of the polyglycolic acid-based polymer is 100,000 to 1,000,000 g / mol, preferably 120,000 to 200,000 g / mol.

3. The low-density polyglycolic acid-based porous modified material according to claim 2, wherein: The weight average molecular weight of the linear polyglycolide homopolymer is above 100,000 g / mol; and / or, The main chain of the polyglycolide graft copolymer is ethylene-vinyl alcohol copolymer, and the side chain includes polyglycolic acid. The structural formula is shown in formula (I): Wherein, x, y, z, and p are all integers, and the sum of x+y+z is not less than 100; and / or, The structural formula of the branched polyglycolide homopolymer is shown in formula (II): Among them, M1, M2, ..., M i are the same or different and are independently selected from imino, nitro or ether bonds; R is a hydrogen atom or an alkane or aromatic hydrocarbon group with a molecular weight of 14 to 1000 g / mol; n1, n2, ..., n i The sum is not less than 40; and / or, i is 1 to 20, preferably 4 to 8.

4. The low-density polyglycolic acid-based porous modified material according to claim 3, wherein: In formula (I), the sum of x+y+z is 100 to 6000, preferably 300 to 2000; and / or, In formula (I), the ratio of x to the sum of x+y+z is 1% to 32%, and / or p is greater than 10, preferably greater than 50.

5. The low-density polyglycolic acid-based porous modified material according to claim 3 or 4, characterized in that: Polyglycolide segments can be obtained by polymerization The monomer, polyvinyl alcohol, and an optional small molecule co-initiator are subjected to melt polymerization in the presence of a catalyst, and then cooled to obtain a mixture of a polyglycolide graft copolymer and a branched polyglycolide homopolymer; preferably, the raw materials also include an antioxidant.

6. The low-density polyglycolic acid-based porous modified material according to claim 5, wherein: The monomer is selected from at least one of methyl glycolate, glycolic acid and glycolide, preferably glycolide; and / or, The alcoholysis degree of the polyvinyl alcohol is 68 to 99%, and / or the polymerization degree of the polyvinyl alcohol is 100 to 6000, preferably 300 to 2000; and / or, The small molecule co-initiator is a small molecule substance having a boiling point greater than 160° C. and containing at least one of a plurality of hydroxyl and amino functional groups; preferably, the molecular weight of the small molecule co-initiator is less than 1000 g / mol, preferably 60 to 300 g / mol; and / or, The catalyst is a salt compound corresponding to at least one of Group IIA-VA metal elements and transition metal elements or an organic guanidine catalyst; preferably, the catalyst is a salt compound corresponding to at least one of Sn, Bi, Mg, Al, Ca, Fe, Mn, Ti and Zn, more preferably a Sn salt; and / or, The antioxidant is selected from hindered phenol antioxidants and / or phosphite antioxidants; and / or, The total amount of the antioxidant used is 0 to 2 parts by mass, preferably 0.01 to 1 part, relative to 100 parts by mass of the monomer.

7. The low-density polyglycolic acid-based porous modified material according to claim 5, wherein: The amount of the polyvinyl alcohol is 0.001 to 10 parts by mass, preferably 0.01 to 1 part by mass, relative to 100 parts by mass of the monomer; and / or The amount of the small molecule co-initiator is 0.001 to 10 parts by mass, more preferably 0.01 to 1 part by mass, relative to 100 parts by mass of the monomer; and / or The amount of the catalyst used is 0.005 to 0.01 parts by mass, preferably 0.01 to 0.2 parts by mass, relative to 100 parts by mass of the monomer; and / or, The conditions for the melt polymerization reaction include: a temperature of 160 to 250° C., preferably 200 to 240° C.; a reaction time of 0.5 to 60 minutes, preferably 1 to 10 minutes; and / or, The melt polymerization reaction is carried out in a melt mixing device; preferably, the melt mixing device is a series combination of one or more of a kettle reactor, a tubular reactor, an internal mixer, a Farrel continuous mixer, a Banbury mixer, a single screw extruder, a multi-screw extruder and a reciprocating single screw extruder, more preferably an internal mixer or a twin-screw extruder; further preferably, The melt polymerization reaction is carried out in a continuous twin-screw extruder. Preferably, the processing temperature is 180-250°C, preferably 210-240°C, the screw speed is 5-300rpm, preferably 40-150rpm, and the aspect ratio is 30-80, preferably 40-70.

8. The low-density polyglycolic acid-based porous modified material according to claim 2, wherein: The particle size of the foamed microsphere modification auxiliary agent powder is 10 to 40 μm, preferably 15 to 25 μm; and / or, The initial foaming temperature of the foaming microsphere modification auxiliary agent powder is 165 to 220° C., preferably 190 to 215° C.; and / or, The foaming peak temperature of the foaming microsphere modification auxiliary agent powder is 210-290° C., preferably 235-245° C.; and / or, The minimum foaming density of the foaming microsphere modified auxiliary powder is less than 0.06g / cm 3 and / or, The initial foaming temperature of the foaming microsphere modified auxiliary agent masterbatch is 125 to 210° C., preferably 185 to 205° C.; and / or, The foaming peak temperature of the foaming microsphere modified auxiliary agent masterbatch is 190 to 250°C, preferably 220 to 240°C.

9. The low-density polyglycolic acid-based porous modified material according to any one of claims 1 to 8, characterized in that: The density of the low-density polyglycolic acid-based porous modified material is 0.7 to 1.5 g / cm 3 and / or, The foaming ratio of the low-density polyglycolic acid-based porous modified material is 1.1 to 2.3, preferably 1.2 to 1.

9.

10. A method for preparing the low-density polyglycolic acid-based porous modified material according to any one of claims 1 to 9, comprising: The components including polyglycolic acid-based polymer, foaming modification aid, thermoplastic compatibilizer, and other additives are extruded and foamed to obtain the low-density polyglycolic acid-based polymer modified material; preferably, the extrusion foaming is carried out in a single-screw extruder or a twin-screw extruder.

11. The method for preparing a low-density polyglycolic acid-based porous modified material according to claim 10, wherein: The extrusion foaming temperature is 210 to 250° C., preferably 220 to 245° C.; and / or, The rotation speed of the single-screw extruder or the twin-screw extruder is 10 to 120 rpm, preferably 15 to 60 rpm.

12. Use of the low-density polyglycolic acid-based porous modified material according to any one of claims 1 to 9 or the low-density polyglycolic acid-based porous modified material obtained by the preparation method according to claim 10 or 11 in surgical drug carriers, orthopedic fixation, tissue repair materials, and foamed disposable products.

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