Thioether ester copolymer containing organic silicon flexible chain segment and preparation method thereof

Abstract

The invention relates to the field of high-molecular polymers, in particular to a thioether ester copolymer containing organic silicon flexible chain segments and a preparation method of the thioether ester copolymer. The low-temperature-resistant epoxy resin is prepared from the following raw materials in parts by weight: 100 to 120 parts of a soft-segment prepolymer, 100 to 200 parts of a hard-segment prepolymer, 10 to 25 parts of an unsaturated epoxy compound, 10 to 20 parts of hydrogen-containing silane, 0.5 to 1 part of a first catalyst and 0.5 to 1 part of a second catalyst, the copolymer combines the flexibility and weather resistance of organic silicon and the strength and chemical resistance of thioether ester, and is suitable for the fields of flexible coatings, sealants, electronic packaging, biomedical materials and the like.

Description

Technical Field

[0001] This invention relates to the field of polymers, and more specifically, to a thioether ester copolymer containing organosilicon flexible segments and a method for preparing the same. Background Technology

[0002] Polyester materials, such as PET and PBT, are widely used due to their good mechanical and processing properties. However, their regular main chain structure and high crystallinity result in high brittleness, poor impact resistance, and severe performance degradation under extreme high and low temperature environments.

[0003] Patent CN117700697A discloses a modified polyester polymer and its preparation method, which introduces long-chain alkyl side chains into the polyester backbone to disrupt crystallization and toughen it. However, this approach significantly sacrifices the heat resistance and rigidity of the polyester material. Patent CN111909365A discloses a method for preparing thioether polyester, which improves the performance of thioether polyester by synthesizing an alternating thioether-ester backbone, combining the flexibility of thioether with the strength of ester bonds at the molecular level. However, there is still room for improvement in the low-temperature toughness and elasticity of this material.

[0004] Therefore, it is of great significance to develop a copolymer with low-temperature performance, thioether bond toughness and chemical stability to meet the requirements of aerospace, high-end electronics, special sealing and other fields for materials to maintain high strength and toughness in an extreme wide temperature range (such as -80℃ to 200℃). Summary of the Invention

[0005] The purpose of this invention is to provide a thioether ester copolymer containing flexible organosilicon segments, which combines the flexibility and weather resistance of organosilicon with the strength and chemical resistance of thioether esters, and is suitable for flexible coatings, sealants, electronic packaging, biomedical materials and other fields.

[0006] Another objective of this invention is to provide a method for preparing a thioether ester copolymer containing organosilicon flexible segments, wherein the reaction conditions are mild and the product structure is controllable.

[0007] The technical problem solved by this invention is achieved by the following technical solution.

[0008] On one hand, embodiments of the present invention provide a thioether ester copolymer containing flexible organosilicon segments, comprising the following raw materials by weight: 100-120 parts of soft segment prepolymer, 100-200 parts of hard segment prepolymer, 10-25 parts of unsaturated epoxy compound, 10-20 parts of hydrogen-containing silane, 0.5-1 part of first catalyst, and 0.5-1 part of second catalyst. The soft segment prepolymer is a polysiloxane with active groups at both ends, and the number average molecular weight of the soft segment prepolymer is 3000-6000 g / mol; The hard segment prepolymer is a diphenol monomer containing ether-sulfur bonds, and an aromatic diacid or its derivative, wherein the number average molecular weight of the hard segment prepolymer is 1000-2000 g / mol.

[0009] In some embodiments of the present invention, the unsaturated epoxy compound is at least one of allyl glycidyl ether, glycidyl methacrylate, glycidyl acrylate, and vinylcyclohexene oxide.

[0010] In some embodiments of the present invention, the hydrogen-containing silane is at least one selected from trimethoxysilane, triethoxysilane, methyldimethoxysilane, and phenyldimethoxysilane.

[0011] On the other hand, embodiments of the present invention provide a method for preparing a thioether ester copolymer containing organosilicon flexible segments, comprising the following steps: S1. Mix the soft segment prepolymer and the hard segment prepolymer with the first solvent respectively; under an inert atmosphere, mix the soft segment prepolymer solution and the hard segment prepolymer solution, add an acid absorbent, heat to 80-90℃, stir and react for 8-12 hours, precipitate, filter, and dry the precipitate to constant weight to obtain the block prepolymer. S2. Mix the block prepolymer, unsaturated epoxy compound and first catalyst from step S1, heat to 90-110℃ under an inert atmosphere, stir and react for 4-8 hours, precipitate, filter, wash and dry to constant weight to obtain an intermediate with unsaturated bonds at both ends. S3. Mix the intermediate from step S2, the second solvent, and acetic acid, then add the second catalyst, heat to 30-40℃, and stir for 0.5-1h; keep the temperature at 35-45℃, add the hydrogen-containing silane dropwise to the reaction system, and stir the reaction for 3-6h; heat the system to 60-70℃, distill under reduced pressure, recover the unreacted hydrogen-containing silane and byproducts, and purify to obtain the thioether ester copolymer.

[0012] In some embodiments of the present invention, the method for preparing the hard segment prepolymer includes the following steps: The bisphenol monomer, aromatic diacid or its derivative, and a third catalyst are added to a reactor. Under continuous nitrogen purging, the mixture is heated to 150-160°C. After the materials melt, stirring is started, and the reaction is maintained at this temperature until the methanol distillation reaches 92-95% of the theoretical amount. The temperature is then raised to 240-250°C, and the reaction continues under vacuum for 0.5-1.5 hours to obtain the hard segment prepolymer.

[0013] In some embodiments of the present invention, in step S1, the first solvent is N-methylpyrrolidone or N,N-dimethylacetamide; the acid absorbent is pyridine or triethylamine.

[0014] In some embodiments of the present invention, the first catalyst is dibutyltin dilaurate.

[0015] In some embodiments of the present invention, the second catalyst is a platinum-vinylsiloxane complex, and the second solvent is anhydrous toluene or isopropanol.

[0016] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: The copolymer provided by this invention combines the flexibility and weather resistance of organosilicon with the strength and chemical resistance of thioether esters, making it suitable for applications such as flexible coatings, sealants, electronic packaging, and biomedical materials.

[0017] Specifically, polysiloxanes with active groups at both ends (number average molecular weight 3000–6000) are used as the soft segment of the copolymer to improve the material's flexibility, low-temperature resistance, hydrophobicity, and biocompatibility. Aromatic diacid derivative prepolymers containing ether-sulfur bonds (number average molecular weight 1000–2000) are used as the hard segment to improve the material's mechanical strength, heat resistance, and chemical stability. The two components form a microphase-separated structure through block copolymerization, synergistically enhancing the material's overall performance. Unsaturated bonds are introduced at both ends of the molecular chain through the ring-opening reaction of unsaturated epoxy compounds with the block prepolymer, enhancing the material's adhesion, reactivity, and compatibility with other polar materials. Crosslinkable siloxane side chains are introduced into the molecular chain through the hydrosilylation reaction of hydrogen-containing silanes, further improving the material's weather resistance, hydrophobicity, and surface properties.

[0018] The preparation method provided by this invention first couples soft and hard segment prepolymers in a solvent to form a well-defined block structure. The use of an acid absorbent ensures efficient reaction. In step S2, through the introduction of epoxy groups and unsaturated bonds, the active hydrogen in the block prepolymer undergoes a ring-opening reaction with the epoxy groups of the unsaturated epoxy compound, introducing unsaturated bonds at both ends of the molecular chain, providing reaction sites for subsequent hydrosilylation, and enhancing the functionality of the molecular chain. In step S3, hydrosilylation is carried out under mild conditions (30-45℃) to avoid high-temperature degradation. Acetic acid acts as a catalyst regulator: at low temperatures, it temporarily coordinates with the platinum catalyst to reduce its activity, avoiding violent exothermic reactions during the addition of hydrogen-containing silanes; upon heating, acetic acid desorbs, restoring catalytic activity and ensuring a stable reaction.

[0019] In summary, the organosilicon-thioether ester block copolymer and its preparation method provided by this invention possess flexibility, strength, heat resistance, weather resistance, and reactivity, and have good application prospects in the field of high-performance polymer materials. The preparation method involves mild process conditions and controllable product structure. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0022] A thioether ester copolymer containing organosilicon flexible segments, comprising, by weight, the following raw materials: 100-120 parts of soft segment prepolymer, 100-200 parts of hard segment prepolymer, 10-25 parts of unsaturated epoxy compound, 10-20 parts of hydrogen-containing silane, 0.5-1 part of first catalyst, and 0.5-1 part of second catalyst. The soft segment prepolymer is a polysiloxane with active groups at both ends, and the number average molecular weight of the soft segment prepolymer is 3000-6000 g / mol; the hard segment prepolymer is a bisphenol monomer containing ether-sulfur bonds, and an aromatic diacid or its derivative, and the number average molecular weight of the hard segment prepolymer is 1000-2000 g / mol.

[0023] The unsaturated epoxy compound is at least one selected from allyl glycidyl ether, glycidyl methacrylate, glycidyl acrylate, and vinylcyclohexene oxide. The hydrogen-containing silane is at least one selected from trimethoxysilane, triethoxysilane, methyldimethoxysilane, and phenyldimethoxysilane.

[0024] The preparation method of the above-mentioned thioether ester copolymer includes the following steps: S1. Mix the soft segment prepolymer and the hard segment prepolymer with the first solvent respectively; under an inert atmosphere, mix the soft segment prepolymer solution and the hard segment prepolymer solution, add an acid absorbent, heat to 80-90℃, stir and react for 8-12 hours, precipitate, filter, and dry the precipitate to constant weight to obtain the block prepolymer. S2. Mix the block prepolymer, unsaturated epoxy compound and first catalyst from step S1, heat to 90-110℃ under an inert atmosphere, stir and react for 4-8 hours, precipitate, filter, wash and dry to constant weight to obtain an intermediate with unsaturated bonds at both ends. S3. Mix the intermediate from step S2, the second solvent, and acetic acid, then add the second catalyst, heat to 30-40℃, and stir for 0.5-1h; keep the temperature at 35-45℃, add the hydrogen-containing silane dropwise to the reaction system, and stir the reaction for 3-6h; heat the system to 60-70℃, distill under reduced pressure, recover the unreacted hydrogen-containing silane and byproducts, and purify to obtain the thioether ester copolymer. In step S1, the soft-segment prepolymer (polysiloxane) has hydroxyl groups (-OH) at both ends, while the hard-segment prepolymer has carboxyl groups (-COOH) or their derivatives (such as acyl chlorides) at both ends. In a polar aprotic solvent (NMP / DMAC), both undergo esterification or acylation to form a block copolymer. The role of the acid absorbent (pyridine / triethylamine) is: a) to neutralize small-molecule acids (such as HCl) in the reaction byproducts, promoting a rightward shift of the reaction equilibrium; b) to act as a catalyst or acid-binding agent, improving the reaction rate and purity.

[0025] The soft segments provide elasticity, while the hard segments provide physical crosslinking points and strength. They are linked by chemical bonds, avoiding excessive phase separation and performance degradation that can occur with simple blending. By controlling the feed ratio and molecular weight of the soft and hard segment prepolymers, the soft and hard segment ratio of the final copolymer can be precisely controlled, allowing for the design of the material's modulus, elasticity, and strength over a wide range.

[0026] In step S2, under the catalysis of dibutyltin dilaurate (a Lewis acid catalyst), these active hydrogens undergo a ring-opening reaction with the epoxy groups of unsaturated epoxy compounds (such as allyl glycidyl ether) to form ether or ester bonds, thereby introducing carbon-carbon double bonds (C=C) to both ends of the molecular chain. This provides sites for subsequent reactions: the introduced C=C double bonds provide functional groups for the next hydrosilylation reaction, enabling side chain grafting. The unsaturated groups themselves can also participate in free radical crosslinking (such as peroxide curing), providing the material with additional curing pathways. The secondary hydroxyl groups or ether bonds formed after the epoxy groups open the ring can slightly improve the polymer's hydrophilicity and adhesion.

[0027] In step S3, under the action of a platinum catalyst (platinum-vinylsiloxane complex, i.e., Karstedt catalyst), the C=C double bond at the end of the intermediate molecular chain undergoes addition with the Si-H bond in a hydrosilane (such as trimethoxysilane, HSi(OCH3)3), forming a stable Si-C bond, thereby grafting silanoxy groups onto the polymer chain end. Acetic acid acts as an inhibitor / stabilizer, temporarily coordinating with the platinum catalyst to reduce its activity at low temperatures and prevent the reaction from being too vigorous when adding the hydrosilane (hydrosilylation is prone to violent exothermic reactions). As the temperature rises to 35-45℃, acetic acid gradually desorbs, the catalytic activity recovers, and the reaction proceeds smoothly and fully. The introduction of crosslinkable side chains: The grafted alkoxysilane (such as -Si(OCH3)3) is the core functional group. In a humid environment, it can hydrolyze to generate silanol (+Si-OH), which then condenses with each other to form a strong Si-O-Si three-dimensional network. This transforms the material from a thermoplastic or thermoplastic elastomer into a moisture-curable thermosetting material, significantly improving its solvent resistance, temperature resistance, and mechanical strength. Organosilicon segments tend to migrate to the material surface, imparting excellent hydrophobicity, weather resistance, stain resistance, and low surface energy to the finished product. Alkoxysilanes can also react with hydroxyl groups on the surface of inorganic substrates (such as glass and metal) to form chemical bonds, thus giving the material excellent adhesion when used as a coating or adhesive.

[0028] The preparation method of the hard segment prepolymer includes the following steps: adding bisphenol monomer, aromatic diacid or its derivative, and catalyst into a reaction vessel, heating under continuous nitrogen gas, raising the temperature to 150-160°C, stirring after the material melts, and maintaining the temperature to ensure that the methanol distillation reaches 92-95% of the theoretical amount; raising the temperature to 240-250°C, and continuing the reaction under vacuum for 0.5-1.5 hours to obtain the hard segment prepolymer.

[0029] In step S1, the first solvent is N-methylpyrrolidone or N,N-dimethylacetamide; the acid absorbent is pyridine or triethylamine. The first catalyst is dibutyltin dilaurate. The second catalyst is a platinum-vinylsiloxane complex, and the second solvent is anhydrous toluene or isopropanol.

[0030] The features and performance of the present invention will be further described in detail below with reference to embodiments. Example 1 1. Preparation of soft segment prepolymer (Cl-PDMS-Cl) Raw materials: α,ω-dihydroxypolydimethylsiloxane (PDMS), molecular weight (Mn) 3000 g / mol (corresponding to m≈27-68), 100 parts by weight. Terephthaloyl chloride, amounted to 3.0-3.2 equivalents of the molar number of hydroxyl groups in PDMS (ensuring complete end-capping with a slight excess). Solvent: anhydrous tetrahydrofuran, amounted to 2-3 times the mass of PDMS (approximately 200-300 mL / 100g PDMS). Inert gas: high-purity nitrogen.

[0031] An inert gas is introduced into a dry three-necked flask equipped with a magnetic stirrer, a drying tube, and a constant-pressure dropping funnel. PDMS and solvent are added and stirred until completely dissolved.

[0032] Cool the system to 0-5°C in an ice-water bath. While stirring, slowly add the dissolved terephthaloyl chloride solution dropwise to the PDMS solution, controlling the dropping rate to keep the reaction temperature below 10°C. After the addition is complete, remove the ice bath and allow the reaction system to naturally rise to room temperature (25°C), then continue stirring for 16 hours.

[0033] The reaction solution was slowly poured into 10 times its volume of cold methanol (-20°C to 0°C) under vigorous stirring to precipitate the product. The product was filtered, and the filter cake was washed three times with cold methanol. The resulting white solid was dried in a vacuum oven at 50°C for 48 hours to constant weight. Cl-PDMS-Cl with acyl chloride groups at both ends was obtained.

[0034] 2. Preparation of hard segment prepolymer (OH-hard segment-OH) Diphenol monomer containing thioether bonds: 4,4'-dihydroxydiphenyl sulfide, 21.8 parts by weight (approximately 0.087 mol). Aromatic diacid derivative: dimethyl terephthalate (DMT), 18.6 parts by weight (approximately 0.096 mol, 1.10 equivalents of the diphenol monomer). Third catalyst: tetrabutyl titanate, at 0.03-0.08 wt% of the total monomer mass (approximately 0.012-0.032 parts by weight). Inert gas: nitrogen.

[0035] In a polymerization reactor equipped with a distillation column, stirrer, thermometer, and nitrogen inlet, bisphenol monomer, DMT, and catalyst are added. The air is purged with nitrogen three times, and then slowly heated under continuous micro-nitrogen protection. The temperature is raised to 150-160°C, and stirring begins once the materials have melted. The reaction is maintained at this temperature, and the distilled methanol is collected. When the methanol distillate reaches 92-95% of the theoretical amount, the transesterification is considered essentially complete.

[0036] Gradually increase the reaction temperature to 240-250℃. Turn on the vacuum system and steadily reduce the system pressure to -0.05 MPa (low vacuum) within 60 minutes. Continue the reaction under these conditions for 1.5 hours. During this stage, small molecules are further removed, and the molecular weight (Mn) of the prepolymer increases to approximately 800-1500.

[0037] Stop the reaction and purge with nitrogen to restore atmospheric pressure. Take a sample and determine Mn by gel permeation chromatography (GPC) or end-group titration. The target Mn is 1800-2500 g / mol. If this target is not reached, the reaction can be repeated under vacuum (-0.05 MPa) for a period of time.

[0038] 3. Prepare the copolymer of this embodiment according to the following proportions and steps: 100 parts of soft segment prepolymer, 150 parts of hard segment prepolymer, 20 parts of unsaturated epoxy compound, 15 parts of hydrogen-containing silane, 0.8 parts of first catalyst, and 1 part of second catalyst.

[0039] Solvent: Anhydrous N-methylpyrrolidone (NMP), used in an amount that makes the total solid content 20 wt%. Acid absorbent: Triethylamine, used in an amount that is 2.1-2.2 equivalents of the number of molar acyl chloride groups in Cl-PDMS-Cl.

[0040] S1. Dissolve the soft-segment prepolymer and the hard-segment prepolymer separately in appropriate amounts of solvent. Under inert gas protection, mix the two solutions and add an acid absorbent. Heat the reaction system to 80-90℃ and stir for 12 hours. The HCl generated during the reaction is captured by the acid absorbent. After the reaction is complete, cool the reaction solution and filter to remove the ammonium salt. Add a large amount of deionized water / methanol mixed solvent (1:1) dropwise to precipitate the product while stirring. Filter and wash several times with methanol. Dry the product in a vacuum oven at 50℃ to constant weight to obtain the block prepolymer.

[0041] S2. Add the block prepolymer, allyl glycidyl ether (unsaturated epoxide), and dibutyltin dilaurate (first catalyst) to a reaction flask and mix thoroughly under nitrogen protection. Heat to 100-110℃ and stir for 8 hours. Dissolve the reaction product in an appropriate amount of THF, then add it dropwise to excess methanol to precipitate. Filter, wash, and vacuum dry to obtain an intermediate with allyl ether structures at both ends (ALLYL-hard segment-soft segment-hard segment-ALLYL).

[0042] S3. In a dry reaction flask, add the intermediate, isopropanol, and acetic acid. Adjust the pH to the target range with acetic acid while stirring. Add the platinum-vinylsiloxane complex (second catalyst) and activate at 30-40°C with stirring for 0.5 hours. Maintain the temperature at 35-45°C and slowly add trimethoxysilane (hydrosilane) dropwise to the reaction system. After the addition is complete, continue stirring at this temperature for 6 hours.

[0043] After the reaction is complete, the system temperature is raised to 60-70℃, and the unreacted hydrogen-containing silane and any possible byproducts are recovered by distillation under reduced pressure (above -0.09 MPa). The copolymer is then obtained by thin-film evaporation.

[0044] Example 2 The difference from Example 1 is that the proportions of the raw materials in the copolymer are as follows: 120 parts of soft segment prepolymer, 200 parts of hard segment prepolymer, 25 parts of unsaturated epoxy compound, 20 parts of hydrogen-containing silane, 0.8 parts of first catalyst, and 1 part of second catalyst.

[0045] The preparation method is the same as in Example 1.

[0046] Example 3 The difference from Example 1 is that the proportions of the raw materials in the copolymer are as follows: 120 parts of soft segment prepolymer, 150 parts of hard segment prepolymer, 10 parts of unsaturated epoxy compound, 10 parts of hydrogen-containing silane, 1 part of first catalyst, and 1 part of second catalyst.

[0047] The preparation method is the same as in Example 1.

[0048] Comparative Example 1 The difference from Example 1 is that no hydrogen-containing silane is added during the preparation process, while the other raw materials and steps are the same as in Example 1.

[0049] Comparative Example 2 The difference from Example 1 is that no unsaturated epoxy compound is added during the preparation process, while the other raw materials and steps are the same as in Example 1.

[0050] Experimental Example The materials obtained from the above examples and comparative examples were used to prepare standard test strips (curing conditions: the strips from examples and comparative example 2 were cured at 23±2℃ and 50±5% RH for 7 days, and comparative example 1 was cured at 120℃ for 2 hours), and performance tests were conducted. The results are shown in Table 1.

[0051] The number-average molecular weight was determined using gel permeation chromatography (GPC). Tensile strength and elongation at break are tested on a universal testing machine at a constant tensile rate (usually 50-500 mm / min, commonly 500 mm / min) until the specimen breaks.

[0052] The glass transition temperature Tg was measured using differential scanning calorimetry (DSC) to obtain Tg values ​​at low and high temperatures. Heat distortion temperature: A constant bending stress of 0.45 MPa is applied to the sample, and the temperature is increased at a rate of 120 °C / h. The temperature at which the bending deformation of the sample reaches the specified amount (0.34 mm) is recorded.

[0053] Volume swelling ratio was tested using the equilibrium swelling method. 1. The sample was prepared into small pieces of the specified shape and mass. 2. The pieces were immersed in an excess of a good solvent (toluene) and sealed for 7 days at a constant temperature (25℃) to ensure swelling equilibrium was reached. 3. The sample was removed, the surface solvent was quickly blotted dry with filter paper, and then weighed. 4. Calculation: Swelling ratio Q = (Swelled mass - Dry mass) / Dry mass × 100%.

[0054] Table 1

[0055] Table 1 shows that the thioether ester copolymers provided in the embodiments of the present invention have hard segments that provide rigidity, and crosslinked networks that bear stress. The thioether ester copolymer of Example 2 has many hard segments, high crosslinking density, and high strength. Soft segments provide ductility, but excessively high crosslinking density restricts chain segment movement. The thioether ester copolymer of Example 3 has many soft segments, low crosslinking density, and high elongation. The higher the crosslinking density of the trimethoxysilane crosslinking network introduced by hydrosilylation, the lower the swelling rate.

[0056] In Comparative Example 1, the hydrosilylation reaction of S3 was missing, and the final product did not contain a trimethoxysilane end group, thus preventing moisture-curing crosslinking. Therefore, the material was a linear thermoplastic polymer that dissolved in toluene.

[0057] Comparative Example 2 lacked the S2 step, and the terminal hydroxyl groups of the block prepolymer failed to be chain-extended by allyl glycidyl ether and introduce allyl groups. Therefore, the subsequent S3 hydrosilylation could not proceed. The final product was essentially an unmodified block prepolymer with a molecular weight only that of the basic block (soft segment + hard segment), far lower than the examples where chain extension and functionalization were achieved through S2 and S3. The low molecular weight resulted in significantly increased material brittleness (extremely low elongation at break). The higher tensile strength may stem from the relatively high hard segment content and the material's brittle fracture characteristics.

[0058] A single heat distortion temperature (Tg) of 105 °C indicates severe miscibility between the soft segment (PDMS) and the hard segment, restricting the movement of the soft segment and causing it to lose its characteristic low-temperature elasticity. This is because the lack of long-chain allyl ether linkers and silane end caps worsens the compatibility between the soft and hard segments, leading to the disruption of the microphase separation structure. The high heat distortion temperature is also related to the dominance of the hard segment phase. The extremely low swelling ratio may stem from the fact that its low molecular weight linear molecules are more likely to precipitate from the solvent rather than form a swelling network.

[0059] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A thioether copolymer containing organosilicon flexible segments, characterized in that, By weight, it includes the following ingredients: 100-120 parts of soft segment prepolymer, 100-200 parts of hard segment prepolymer, 10-25 parts of unsaturated epoxy compound, 10-20 parts of hydrogen-containing silane, 0.5-1 part of first catalyst, and 0.5-1 part of second catalyst. The soft segment prepolymer is a polysiloxane with active groups at both ends, and the number average molecular weight of the soft segment prepolymer is 3000-6000 g / mol; The hard segment prepolymer is a diphenol monomer containing ether-sulfur bonds, and an aromatic diacid or its derivative, wherein the number average molecular weight of the hard segment prepolymer is 1000-2000 g / mol.

2. The thioether copolymer containing organosilicon flexible segments according to claim 1, characterized in that, The unsaturated epoxy compound is at least one of allyl glycidyl ether, glycidyl methacrylate, glycidyl acrylate, and vinylcyclohexene oxide.

3. The thioether copolymer containing organosilicon flexible segments according to claim 1, characterized in that, The hydrogen-containing silane is at least one of trimethoxysilane, triethoxysilane, methyldimethoxysilane, and phenyldimethoxysilane.

4. A method for preparing a thioether ester copolymer containing organosilicon flexible segments as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Mix the soft segment prepolymer and the hard segment prepolymer with the first solvent respectively; under an inert atmosphere, mix the soft segment prepolymer solution and the hard segment prepolymer solution, add an acid absorbent, heat to 80-90℃, stir and react for 8-12 hours, precipitate, filter, and dry the precipitate to constant weight to obtain the block prepolymer. S2. Mix the block prepolymer, unsaturated epoxy compound and first catalyst from step S1, heat to 90-110℃ under an inert atmosphere, stir and react for 4-8 hours, precipitate, filter, wash and dry to constant weight to obtain an intermediate with unsaturated bonds at both ends. S3. Mix the intermediate from step S2, the second solvent, and acetic acid, then add the second catalyst, heat to 30-40℃, and stir for 0.5-1h; keep the temperature at 35-45℃, add the hydrogen-containing silane dropwise to the reaction system, and stir the reaction for 3-6h; heat the system to 60-70℃, distill under reduced pressure, recover the unreacted hydrogen-containing silane and byproducts, and purify to obtain the thioether ester copolymer.

5. The method for preparing the thioether ester copolymer containing organosilicon flexible segments according to claim 4, characterized in that, The method for preparing the hard segment prepolymer includes the following steps: The bisphenol monomer, aromatic diacid or its derivative, and a third catalyst are added to a reactor. Under continuous nitrogen purging, the mixture is heated to 150-160°C. After the materials melt, stirring is started, and the reaction is maintained until the methanol distillation reaches 92-95% of the theoretical amount. The temperature is then raised to 240-250°C, and the reaction is continued under vacuum for 0.5-1.5 hours to obtain the hard segment prepolymer.

6. The method for preparing the thioether ester copolymer containing organosilicon flexible segments according to claim 4, characterized in that, In step S1, the first solvent is N-methylpyrrolidone or N,N-dimethylacetamide; the acid absorbent is pyridine or triethylamine.

7. The method for preparing the thioether copolymer containing organosilicon flexible segments according to claim 4, characterized in that, The first catalyst is dibutyltin dilaurate.

8. The method for preparing the thioether copolymer containing organosilicon flexible segments according to claim 4, characterized in that, The second catalyst is a platinum-vinylsiloxane complex, and the second solvent is anhydrous toluene or isopropanol.

Images