A macromolecular radiation resistant stabilizer, its preparation method and modified radiation resistant medical polymer material

Abstract

The application provides a macromolecular radiation-resistant stabilizer, a preparation method thereof and a modified radiation-resistant medical polymer material. The preparation raw material of the radiation-resistant stabilizer comprises at least one olefin derivative of thioctic acid and at least one C10-C25 olefin. The radiation-resistant stabilizer can be used to solve the problems of oxidation degradation, discoloration and brittleness of the existing polyolefin medical polymer material after radiation sterilization, and simultaneously reduce the material cost and promote the wide application of radiation sterilization in medical devices. The radiation-resistant medical polymer material modified by the macromolecular radiation-resistant stabilizer can realize long-term radiation resistance, low release and mechanical property regulation.

Description

Technical Field

[0001] This invention belongs to the field of medical polymer materials technology, and particularly relates to a macromolecular radiation-resistant stabilizer, its preparation method, and modified radiation-resistant medical polymer materials. Background Technology

[0002] Currently, most medical devices are sterilized using ethylene oxide. However, ethylene oxide is carcinogenic, and the residues left after sterilization are harmful to the health of medical staff and patients. Irradiation sterilization, due to its advantages such as high efficiency, environmental friendliness, and no residue, is gradually showing its potential to replace traditional ethylene oxide sterilization technology. However, conventional medical polymer materials are prone to oxidative degradation, discoloration, and embrittlement after irradiation, leading to a decline in their performance and failure to meet the requirements for use in medical devices. Furthermore, small molecule additives may be released during the irradiation process, threatening the safety of medical devices.

[0003] Most current radiation-resistant materials use hindered amine (HALS) or phenolic antioxidants to improve their radiation resistance, but they still have drawbacks such as residual precipitates and insufficient radiation resistance. These problems limit their widespread application in radiation sterilization. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a macromolecular radiation-resistant stabilizer, its preparation method, and a modified radiation-resistant medical polymer material. When applied to medical polymer materials, this radiation-resistant stabilizer can achieve long-term radiation resistance, low precipitation, and controllable mechanical properties.

[0005] This invention provides a macromolecular radiation-resistant stabilizer, the raw materials of which include at least one olefinic derivative of lipoic acid and at least one C10-C25 olefin.

[0006] Preferably, the olefinic derivative of the lipoic acid is selected from any one of formulas 101 to 106:

[0007] Formula 101; Equation 102;

[0008] Formula 103; Equation 104;

[0009] Formula 105; Equation 106;

[0010] In Equations 103 to 106, n is an integer greater than 0.

[0011] Preferably, the C10-C25 olefins are selected from one or more of formulas 201-204:

[0012] Formula 201; Equation 202;

[0013] Equation 203; Equation 204;

[0014] In Equations 201 to 204, m is independently selected from 8 to 20.

[0015] Preferably, the molecular weight of the macromolecular radiation-resistant stabilizer is 5000~10000 g / mol.

[0016] This invention provides a method for preparing the macromolecular radiation-resistant stabilizer described in the above-mentioned technical solution, comprising the following steps:

[0017] Under a nitrogen atmosphere, the alkylated derivative of thioctic acid is copolymerized with a C10-C25 olefin initiator, precipitated, and dried to obtain a macromolecular radiation-resistant stabilizer.

[0018] Preferably, the copolymerization reaction is carried out at a temperature of 70-85°C for 5-24 hours.

[0019] This invention provides a modified radiation-resistant medical polymer material, which, by mass, comprises 100 parts of a polyolefin thermoplastic elastomer, 3-10 parts of the macromolecular radiation-resistant stabilizer described in the above technical solution, and 3-10 parts of other additives.

[0020] Preferably, the molecular weight of the polyolefin thermoplastic elastomer is 100,000 to 250,000.

[0021] Preferably, the other additives include one or more of auxiliary antioxidants, plasticizers, and auxiliary mixing agents;

[0022] The auxiliary antioxidant is selected from one or more of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris[2,4-di-tert-butylphenyl] phosphite, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite, cerium dioxide nanoparticles, and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid;

[0023] The plasticizer is selected from one or more of dioctyl phthalate, dioctyl sebacate, tricresyl phosphate, and diisononyl ester;

[0024] The auxiliary mixture is selected from at least one of glyceryl stearate, polydimethylsiloxane, and polyethylene wax.

[0025] This invention provides a method for preparing the modified radiation-resistant medical polymer material described in the above technical solution, comprising the following steps:

[0026] 100 parts of polyolefin thermoplastic elastomer, 3-10 parts of macromolecular radiation-resistant stabilizer, and 3-10 parts of other additives are mixed, granulated, and dried to obtain a modified radiation-resistant medical polymer material.

[0027] This invention provides a macromolecular radiation-resistant stabilizer, prepared from raw materials including at least one olefinic derivative of lipoic acid and at least one C10-C25 olefin. This radiation-resistant stabilizer can address the problems of oxidative degradation, discoloration, and brittleness that easily occur in existing polyolefin-based medical polymers after radiation sterilization, while simultaneously reducing material costs and promoting the widespread application of radiation sterilization in medical devices. Compared to other radiation-resistant modification strategies, the radiation-resistant medical polymer materials modified with this novel macromolecular radiation-resistant stabilizer can achieve long-lasting radiation resistance, low precipitation, and regulated mechanical properties. Attached Figure Description

[0028] Figure 1 The 1H NMR spectrum of the macromolecular radiation-resistant agent prepared in Example 1 of this invention;

[0029] Figure 2 The 1H NMR spectrum of the macromolecular radiation-resistant agent prepared in Example 2 of this invention;

[0030] Figure 3 The 1H NMR spectrum of the macromolecular radiation-resistant agent prepared in Example 3 of this invention;

[0031] Figure 4 The 1H NMR spectrum of the macromolecular radiation-resistant agent prepared in Example 4 of this invention;

[0032] Figure 5 The nuclear magnetic resonance hydrogen spectrum of the macromolecular radiation-resistant agent prepared in Example 5 of this invention. Detailed Implementation

[0033] This invention provides a macromolecular radiation-resistant stabilizer, the raw materials of which include at least one olefinic derivative of lipoic acid and at least one C10-C25 olefin.

[0034] This invention relates to a strategy for radiation-resistant modification of polyolefin-based medical polymers based on the aforementioned macromolecular radiation-resistant stabilizer, and its application, suitable for radiation sterilization of medical devices. It can solve problems such as oxidative degradation, discoloration, and brittleness that easily occur in existing medical polymers after radiation sterilization, while reducing material costs and promoting the widespread application of radiation sterilization in medical devices. Compared to other radiation-resistant modification strategies, the radiation-resistant medical polymer based on thioctic acid modification provided by this invention can achieve long-lasting radiation resistance, low precipitation, and tunable mechanical properties.

[0035] The radiation-resistant stabilizer provided by this invention possesses excellent biocompatibility. The macromolecular radiation-resistant stabilizer, rich in long alkyl chains, can form chain entanglements with the matrix. Its large volume also results in a small migration free path, thus exhibiting low precipitation characteristics. No harmful substances are released after irradiation, meeting the safety standards for medical devices and suitable for medical devices that come into contact with blood and implantable medical devices. The disulfide bonds contained in the radiation-resistant stabilizer of this invention can be dynamically and reversibly regenerated, enabling it to function stably for a long period during irradiation, inhibiting oxidative degradation and discoloration reactions of polymer materials. The radiation-resistant stabilizer can significantly improve the radiation resistance of materials even at low addition levels.

[0036] The olefinic derivatives of lipoic acid described in this invention are selected from any one of formulas 101 to 106:

[0037] Formula 101; Equation 102;

[0038] Formula 103; Equation 104;

[0039] Formula 105; Equation 106;

[0040] In Equations 103 to 106, n is an integer greater than 0.

[0041] In a specific embodiment of the present invention, the olefinic derivative of lipoic acid is of formula 103 and n=2; or of formula 104 and n=2; or of formula 105 and n=6; or of formula 106 and n=6; or of formula 103 and n=1.

[0042] The C10-C25 olefins described in this invention are selected from one or more of formulas 201-204:

[0043] Formula 201; Equation 202;

[0044] Equation 203; Equation 204;

[0045] In Equations 201 to 204, m is independently selected from 8 to 20; specifically, the value of m is 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20.

[0046] In a specific embodiment of the present invention, the C10 to C25 olefins are selected from C18 long-chain olefins of formula 201; or C12 long-chain olefins of formula 203; or C20 long-chain olefins of formula 202; or C16 long-chain olefins of formula 204; or C14 long-chain olefins of formula 201.

[0047] The preparation method of the macromolecular radiation-resistant stabilizer described in this invention includes the following steps:

[0048] Under a nitrogen atmosphere, the alkylated derivative of thioctic acid is copolymerized with a C10-C25 olefin initiator, precipitated, and dried to obtain a macromolecular radiation-resistant stabilizer.

[0049] In this invention, the initiator is a peroxide; the peroxide is benzoyl peroxide (BPO); the initiator accounts for 1 to 3 wt% of the total amount of the thioctic acid alkylation derivative and olefin; specifically, it can be 1 wt%, 1.2 wt%, 1.4 wt%, 1.6 wt%, 1.8 wt%, 2.0 wt%, 2.2 wt%, 2.4 wt%, 2.6 wt%, 2.8 wt%, or 3 wt%.

[0050] In this invention, the molar ratio of the thioctic acid alkylation derivative to the C10-C25 olefin is 1:(0.5-3); in specific embodiments, the molar ratio of the thioctic acid alkylation derivative to the C10-C25 olefin is 1:2 or 1:3.

[0051] In this invention, the temperature of the copolymerization reaction is 70~85℃, specifically 70℃, 75℃, 80℃ or 85℃; the time is 5~24h, specifically 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h or 24h.

[0052] This invention requires controlling the temperature of the copolymerization reaction and the amount of initiator to avoid excessively high molecular weight (>10,000), which would result in poor dispersibility.

[0053] In this invention, the reaction product is preferably precipitated with ethanol, vacuum dried, and then pulverized to a particle size ≤100μm.

[0054] This invention provides a modified radiation-resistant medical polymer material, the raw materials of which include 100 parts of polyolefin thermoplastic elastomer, 3-10 parts of the macromolecular radiation-resistant stabilizer described in the above technical solution, and 3-10 parts of other additives.

[0055] The macromolecular radiation-resistant stabilizer provided by this invention, when applied to medical polymer materials, can effectively inhibit oxidative degradation and discoloration reactions during irradiation, solving the problem of performance degradation of existing materials after irradiation. This macromolecular radiation-resistant stabilizer has multiple long alkyl side chains, which can enhance the compatibility between the macromolecular radiation-resistant stabilizer and the matrix through chain entanglement, achieving low precipitation. Furthermore, the mechanical properties of the composite material can be adjusted by controlling the amount added. This modified radiation-resistant medical polymer material is low-cost, promoting the widespread application of radiation sterilization in medical devices.

[0056] During irradiation, medical polymer materials generate a large number of free radicals, leading to oxidative degradation. The dynamic cyclic disulfide in the stabilizer possesses excellent reducing properties, enabling it to capture these free radicals and inhibit chain oxidation reactions. The dynamic cyclic disulfide structure can absorb irradiation energy and release it as heat through exchange reactions, reducing damage to the polymer backbone. The cyclic disulfide structure can generate various non-covalent interactions with other auxiliaries, improving interfacial issues and synergistically enhancing antioxidant properties. During irradiation, the sulfur ring can react with carbon free radicals generated by macromolecular chain breakage to achieve cross-linking, thereby preventing a decline in mechanical properties. After irradiation sterilization, medical polymer materials can effectively dissipate energy and undergo internal cross-linking for secondary reinforcement, thus maintaining excellent mechanical properties and appearance, without significant oxidative degradation, discoloration, or brittleness.

[0057] In this invention, the molecular weight of the polyolefin thermoplastic elastomer is 100,000 to 250,000. The polyolefin thermoplastic elastomer is selected from polypropylene, polyvinyl chloride, SEBS resin, and other polyolefin thermoplastic elastomers.

[0058] In this invention, the other additives include one or more of auxiliary antioxidants, plasticizers, and auxiliary mixing agents;

[0059] The auxiliary antioxidant is selected from one or more of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris[2,4-di-tert-butylphenyl] phosphite, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite, cerium dioxide nanoparticles, and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid; the auxiliary antioxidant can synergistically scavenge free radicals with macromolecular radiation-resistant stabilizers.

[0060] The plasticizer is selected from one or more of dioctyl phthalate, dioctyl sebacate, tricresyl phosphate, and diisononyl ester;

[0061] The auxiliary mixing agent is selected from at least one of glyceryl stearate, polydimethylsiloxane, and polyethylene wax. This auxiliary mixing agent helps the raw materials mix evenly, also acts as a lubricant, and improves processing performance.

[0062] In this invention, the macromolecular radiation-resistant stabilizer is 3-10 parts, specifically 3, 4, 5, 6, 7, 8, 9, or 10 parts. Specifically, it is prepared by copolymerizing a lipoic acid olefin derivative with the structure shown in Formula 103 with a C18 long-chain olefin, having a molecular weight of 8000; or by copolymerizing a lipoic acid olefin derivative with the structure shown in Formula 104 with a C12 long-chain olefin, having a molecular weight of 6000; or by copolymerizing a lipoic acid olefin derivative with the structure shown in Formula 105 with a C20 long-chain olefin, having a molecular weight of 9000; or by copolymerizing a lipoic acid olefin derivative with the structure shown in Formula 106 with a C16 long-chain olefin, having a molecular weight of 7000; or by copolymerizing a lipoic acid olefin derivative with the structure shown in Formula 103 with a C14 long-chain olefin, having a molecular weight of 7500.

[0063] This invention provides a method for preparing the modified radiation-resistant medical polymer material described in the above technical solution, comprising the following steps:

[0064] 100 parts of polyolefin thermoplastic elastomer, 3-10 parts of macromolecular radiation-resistant stabilizer, and 3-10 parts of other additives are mixed, granulated, and dried to obtain a modified radiation-resistant medical polymer material.

[0065] If the polyolefin thermoplastic elastomer is polyvinyl chloride, the mixing temperature should be below 200℃ to avoid decomposition; the feed section temperature should be 180℃, the melting section temperature should be 195℃, and the die head temperature should be 200℃.

[0066] If the polyolefin thermoplastic elastomer is polypropylene / SEBS resin, the temperature can be appropriately increased to improve fluidity; the feed section temperature is 185℃, the melting section temperature is 200℃, and the die head temperature is 210℃.

[0067] If other additives in this invention are selected from auxiliary mixing agents and / or plasticizers, they need to be added at the initial stage of mixing to ensure that the auxiliary antioxidants and macromolecular radiation-resistant stabilizers uniformly coat the elastomer particles.

[0068] The macromolecular radiation-resistant stabilizer provided by this invention is a macromolecular polymer formed by copolymerizing an olefinic derivative of lipoic acid with a long-chain olefin. Rich in five-membered disulfide rings, it can absorb irradiation energy and scavenge free radicals, effectively inhibiting the oxidative degradation of polymer materials during irradiation. Through disulfide bond exchange reactions, this macromolecular radiation-resistant stabilizer can be reversibly regenerated to achieve long-term radiation resistance. Furthermore, during irradiation, the sulfur rings can react with the terminal carbon free radicals of the broken macromolecules to achieve cross-linking, thereby preventing a decline in mechanical properties. The long alkyl chains can enhance the compatibility between the macromolecular radiation-resistant stabilizer and the matrix through chain entanglement, achieving low precipitation, and the mechanical properties of the composite material can be adjusted by controlling the amount added.

[0069] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, provides a macromolecular radiation-resistant stabilizer, its preparation method, and a modified radiation-resistant medical polymer material provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0070] Example 1

[0071] Synthesis of macromolecular radiation-resistant stabilizers: A lipoic acid olefin derivative (structural formula 103, n=2) was mixed with a C18 long-chain olefin monomer (structural formula 201) at a molar ratio of 1:3. 0.5% benzoyl peroxide (BPO) was added as an initiator, and the reaction was carried out at 80°C for 6 hours under nitrogen protection to obtain a copolymer. The reaction product was precipitated with ethanol, vacuum dried, and then pulverized into a powder with a particle size ≤100 μm for later use.

[0072] Composite material preparation: 100 parts by weight of polypropylene granules (molecular weight 150,000), 5 parts by weight of macromolecular radiation-resistant stabilizer powder (lipoic acid olefin derivative and C18 long-chain olefin copolymer, molecular weight 8,000), 5 parts by weight of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, and 2 parts by weight of white oil (auxiliary mixing agent) were added to a high-speed mixer (800 rpm) and mixed for 15 minutes until homogeneous, ensuring uniform adhesion of the additives. The mixture was then added to a twin-screw extruder (L / D ratio 40:1) with the following temperature settings: feed section 180℃, melt section 195℃, die head 200℃; screw speed 150 rpm) for melt blending and extrusion granulation. The granules were dried in an 80℃ oven for 4 hours and injection molded into test specimens (die temperature 50℃, specimen thickness 2.0 mm). Subsequent performance test results are shown in Table 1. This material can be used to prepare radiation-resistant injectors.

[0073] Example 2

[0074] Synthesis of macromolecular radiation-resistant stabilizers: The alpha-lipoic acid olefin derivative (structural formula 104, n=2) was copolymerized with a C12 long-chain olefin (structural formula 203) at a molar ratio of 1:2, and the rest was the same as in Example 1.

[0075] Composite material preparation: 100 parts by weight of SEBS resin (molecular weight 200,000), 8 parts by weight of macromolecular radiation-resistant stabilizer (lipoic acid olefin derivative and C12 long-chain olefin copolymer, molecular weight 6,000), and 3 parts by weight of cerium dioxide nanoparticles (particle size 30 nm) were mixed in a mixer (temperature 190℃, speed 60 rpm) for 20 minutes. The melt was extruded and granulated using a single-screw extruder (temperature setting: 190℃→200℃→205℃), and subsequent drying and molding were the same as in Example 1. The performance test results are shown in Table 1, indicating that it can be used to prepare radiation-resistant infusion set tubing.

[0076] Example 3

[0077] Synthesis of macromolecular radiation-resistant stabilizers: The alpha-lipoic acid olefin derivative (structural formula 105, n=6) was copolymerized with a C20 long-chain olefin (structural formula 202) at a molar ratio of 1:4, and the rest was the same as in Example 1.

[0078] Composite material preparation: 100 parts by weight of polyvinyl chloride (molecular weight 120,000), 10 parts by weight of macromolecular radiation-resistant stabilizer powder (lipoic acid derivative and C20 long-chain olefin copolymer, molecular weight 9,000), 8 parts by weight of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 5 parts by weight of plasticizer DOP were mixed in a high-speed mixer (temperature 90℃, speed 1000rpm) for 30 minutes. The mixture was then kneaded in a two-roll mill (roll temperature 160℃) for 10 minutes, compressed into tablets, and cut into test samples. The performance test results are shown in Table 1, indicating that the material can be used to prepare radiation-resistant blood bags.

[0079] Example 4

[0080] Synthesis of macromolecular radiation-resistant stabilizers: The alpha-lipoic acid olefin derivative (structural formula 106, n=6) was copolymerized with a C16 long-chain olefin (structural formula 204) at a molar ratio of 1:3, and the rest was the same as in Example 1.

[0081] Composite material preparation: 100 parts by weight of polypropylene (molecular weight 180,000), 10 parts by weight of macromolecular radiation-resistant stabilizer (lipoic acid derivative and C16 long-chain olefin copolymer, molecular weight 7,000), and 5 parts by weight of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate were extruded and granulated in a twin-screw extruder (temperature 185℃→200℃→210℃), with the remaining steps the same as in Example 1. Performance test results are shown in Table 1. It can be used to prepare radiation-resistant transparent medicine bottles.

[0082] Example 5

[0083] Synthesis of macromolecular radiation-resistant stabilizers: The alpha-lipoic acid olefin derivative (structural formula 103, n=1) was copolymerized with a C14 long-chain olefin (structural formula 201) at a molar ratio of 1:2, and the rest was the same as in Example 1.

[0084] Composite material preparation: 100 parts by weight of SEBS resin (molecular weight 220,000), 6 parts by weight of macromolecular radiation-resistant stabilizer (lipoic acid derivative and C14 long-chain olefin copolymer, molecular weight 7,500), and 7 parts by weight of pentaerythritol diphosphite were mixed in a Banbury mixer (temperature 195℃, speed 70 rpm) for 25 minutes. Subsequent processes were the same as in Example 2. Performance test results are shown in Table 1. It can be used to prepare radiation-resistant elastic seals.

[0085] Blank example (without stabilizer):

[0086] 100 parts by weight of polypropylene (molecular weight 150,000) and 3 parts by weight of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester were mixed in a high-speed mixer (800 rpm) for 15 minutes. The mixture was then extruded and granulated using a twin-screw extruder (temperature 180℃→195℃→200℃), with the rest of the process the same as in Example 1.

[0087] Comparative Example 1 (long-chain olefins only):

[0088] 100 parts by weight of polypropylene (molecular weight 150,000), 3 parts of C18 long-chain polyolefin (not copolymerized with thioctic acid derivatives), and 3 parts of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate were directly mixed (without a stabilizer synthesis step). The mixture was extruded and granulated using a twin-screw extruder (temperature 180℃→195℃→200℃), with the rest of the process the same as in Example 1.

[0089] Test metrics:

[0090] Irradiation conditions: Electron beam or gamma ray irradiation, dose of 25~50 kGy;

[0091] Tensile property test: The tensile properties of the samples were tested according to GB / T 1040-2006, with a tensile speed of 50 mm / min and a temperature of 25℃.

[0092] Transparency test: The transmittance and haze of the sample were tested according to GB / T 2410-2008, and the sample thickness was 2.0 mm.

[0093] Color difference value ΔE test: The test is conducted using a colorimeter. Based on the degree and level of color change of the five gray sample cards, it is determined whether the required level is met.

[0094] Yellowness index (Yi) test: assessed according to the color change grading range of GB / T 1766-1995;

[0095] Oxidation Induction Time (OIT): The antioxidant properties of the material are evaluated according to GB / T 19466.6-2009;

[0096] Biocompatibility: Cytotoxicity, sensitization, and other tests were conducted according to ISO 10993 standard;

[0097] Leachable analysis: Detects whether the stabilizer releases harmful substances after irradiation.

[0098] Table 1

[0099]

[0100] As shown in Table 1, Examples 1-5 all added a macromolecular radiation-resistant stabilizer copolymerized with lipoic acid derivatives and long-chain olefins, and combined with different inorganic nanoparticle additives. The performance parameters showed that the mechanical properties were well retained after irradiation (tensile strength decreased by ≤15%), light transmittance was ≥75%, ΔE≤1.5, and the leachable matter was extremely low, and the biocompatibility was excellent.

[0101] Blank example: Without the addition of radiation-resistant stabilizers, the tensile strength decreased significantly (35.7%) after irradiation, the light transmittance was low, the ΔE was as high as 4.5, and the leachable matter exceeded the standard, and the biocompatibility did not meet the standard.

[0102] Comparative Example 1: Only long-chain olefins were added (without thioctic acid derivatives). The radiation resistance was slightly better than the blank example (tensile strength decreased by 20%), but far inferior to the example, indicating that the chemical stabilization mechanism of thioctic acid derivatives is crucial for performance improvement.

[0103] As shown in the above embodiments, this invention provides a macromolecular radiation-resistant stabilizer, the raw materials of which include at least one olefinic derivative of lipoic acid and at least one C10-C25 olefin. This radiation-resistant stabilizer can solve the problems of oxidative degradation, discoloration, and brittleness that easily occur in existing polyolefin medical polymer materials after radiation sterilization, while reducing material costs and promoting the widespread application of radiation sterilization in medical devices. Compared with other radiation-resistant modification strategies, the radiation-resistant medical polymer materials modified with the novel macromolecular radiation-resistant stabilizer can achieve long-term radiation resistance, low precipitation, and controllable mechanical properties. Experimental results show that the tensile strength of the irradiated medical polymer material is 23-40 MPa, the light transmittance is 78-90%, the oxidation induction time is 48-60 min, and the yellowness index is ≤1.8.

[0104] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A macromolecular radiation-resistant stabilizer, characterized in that, The raw materials for preparation include at least one olefinic derivative of thioctic acid and at least one C10-C25 olefin.

2. The macromolecular radiation-resistant stabilizer according to claim 1, characterized in that, The olefinic derivative of the lipoic acid is selected from any one of formulas 101 to 106: Formula 101; Equation 102; Formula 103; Equation 104; Formula 105; Equation 106; In Equations 103 to 106, n is an integer greater than 0.

3. The macromolecular radiation-resistant stabilizer according to claim 1, characterized in that, C10 to C25 olefins are selected from one or more of formulas 201 to 204: Formula 201; Equation 202; Equation 203; Equation 204; In Equations 201 to 204, m is independently selected from 8 to 20.

4. The macromolecular radiation-resistant stabilizer according to claim 1, characterized in that, The molecular weight of the macromolecular radiation-resistant stabilizer is 5000~10000 g / mol.

5. A method for preparing the macromolecular radiation-resistant stabilizer according to any one of claims 1 to 4, comprising the following steps: Under a nitrogen atmosphere, the alkylated derivative of thioctic acid is copolymerized with a C10-C25 olefin initiator, precipitated, and dried to obtain a macromolecular radiation-resistant stabilizer.

6. The preparation method according to claim 5, characterized in that, The copolymerization reaction is carried out at a temperature of 70-85℃ for 5-24 hours.

7. A modified radiation-resistant medical polymer material, characterized in that, The raw materials for preparation, by mass, include 100 parts of polyolefin thermoplastic elastomer, 3-10 parts of macromolecular radiation-resistant stabilizer as described in any one of claims 1 to 4, and 3-10 parts of other additives.

8. The modified radiation-resistant medical polymer material according to claim 7, characterized in that, The molecular weight of the polyolefin thermoplastic elastomer is 100,000 to 250,000.

9. The modified radiation-resistant medical polymer material according to claim 5, characterized in that, The other additives include one or more of auxiliary antioxidants, plasticizers, and auxiliary mixing agents; The auxiliary antioxidant is selected from one or more of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris[2,4-di-tert-butylphenyl] phosphite, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite, cerium dioxide nanoparticles, and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid; The plasticizer is selected from one or more of dioctyl phthalate, dioctyl sebacate, tricresyl phosphate, and diisononyl ester; The auxiliary mixture is selected from at least one of glyceryl stearate, polydimethylsiloxane, and polyethylene wax.

10. A method for preparing the modified radiation-resistant medical polymer material according to claim 7, comprising the following steps: 100 parts of polyolefin thermoplastic elastomer, 3-10 parts of macromolecular radiation-resistant stabilizer, and 3-10 parts of other additives are mixed, granulated, and dried to obtain a modified radiation-resistant medical polymer material.

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