Shape memory molecule enhanced high-elasticity insole material and preparation method thereof

Abstract

The invention discloses a shape memory molecule enhanced high-elasticity insole material and a preparation method thereof, belongs to the technical field of insole preparation, and is used for solving the technical problem that the rebound resilience and antibacterial property of an insole material in the prior art need to be further improved. The preparation method specifically comprises the following steps: carrying out surface modification and post-treatment on memory foam to obtain the composite memory foam, carrying out a reaction on a prepared modified polyamide acid terminated anhydride group and a prepared amino group modified on fiber sponge, tightly combining the two groups, carrying out amidation on the material by using acetic anhydride, and carrying out low-temperature freezing foaming to obtain the composite memory foam. The preparation method comprises the following steps: preparing memory foam, complexing imidazole groups modified on the surface of the memory foam with zinc ions, carrying out quaternization to obtain composite memory foam, filling silica sol into the foam by utilizing vacuum, and hydrolyzing by taking an organic metal framework as a matrix to finally prepare the high-elasticity insole material.

Description

Technical Field

[0001] The present invention relates to the technical field of insole preparation, and in particular to a high-elasticity insole material reinforced with shape memory molecules and a preparation method thereof. Background Art

[0002] High-elasticity insole materials enhanced with shape memory molecules have experienced significant development in terms of resilience and antibacterial properties. Early insoles mainly used EVA or PU foam, which had basic cushioning functions but insufficient resilience and were prone to collapse after long-term use. With the advancement of materials science, researchers have introduced shape memory polymers such as PU modified copolymers, which achieve rapid rebound and lasting deformation recovery after stress release through cross-linked structures, significantly improving dynamic cushioning and rebound efficiency. The introduction of nanomaterials further optimizes the elastic modulus and energy feedback performance. In terms of antibacterial properties, traditional additives have problems of precipitation and drug resistance. In recent years, the use of block antibacterial polymers or SMP-loaded natural antibacterial agents has become a trend. They have broad-spectrum antibacterial properties and are long-lasting and biosafe, promoting their widespread application in sports, medical treatment and personalized wear.

[0003] For example, the prior art CN113185666B discloses a highly elastic insole and a production process. Specifically, the insole is made of raw materials such as polytetrahydrofuran diol, polyether-modified diphenylmethane diisocyanate, a catalyst, a chain extender, and water. The polytetrahydrofuran diol, catalyst, chain extender, and water are uniformly stirred to obtain a stock, polyether-modified diphenylmethane diisocyanate is added to the stock, and stirred to obtain an intermediate material. The intermediate material is injected into a mold to form the insole, and then cut to obtain the insole. The insole has both good elasticity and tensile properties, is comfortable to wear, and has a long service life.

[0004] However, the above invention utilizes polyether-modified diphenylmethane diisocyanate and tetrahydrofuran to polymerize, extend the chain to obtain an intermediate material, and inject it into a mold for molding to obtain an elastic insole. However, the single cross-linked network and simple porous structure of polyurethane foam are used, and there is a lack of support from a multi-level composite system, resulting in limited improvement in rebound rate, antibacterial properties and tensile strength. The elastic structure generated only by the reaction of polytetrahydrofuran diol and modified diisocyanate is relatively simple, making it difficult to achieve efficient deformation recovery and mechanical stability. Moreover, only adding antibacterial powder lacks a deep chemical synergistic mechanism, resulting in limited antibacterial effect and insufficient durability, which leads to the need for further improvement in the composite performance of the insole material. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-elasticity insole material reinforced with shape memory molecules and a preparation method thereof, so as to solve the technical problem that the rebound performance and antibacterial properties of the insole material in the prior art need to be further improved.

[0006] The object of the present invention can be achieved by the following technical solution: A method for preparing a high-elasticity insole material reinforced with shape memory molecules comprises the following steps:

[0007] S1. Mixing composite polystyrene and o-xylene to obtain a spinning solution, performing air-spinning on the spinning solution, and post-treating to obtain a fiber sponge;

[0008] S2, adding fiber sponge, modified polyamic acid and N,N-dimethylformamide into a reactor, lowering the temperature of the reactor to 0-5°C, keeping the temperature for reaction for 20-30 minutes, raising the temperature of the vacuum reactor to 70-80°C, adding acetic anhydride and triethylamine, keeping the temperature for reaction for 10-20 minutes, and post-processing to obtain memory foam;

[0009] The reaction principle for preparing memory foam is as follows: the amino groups on the fiber sponge and the anhydride groups at the ends of the modified polyamic acid are mixed in N,N-dimethylformamide. After pretreatment at 0-5°C, acetic anhydride and triethylamine are added as dehydrating agents and catalysts to promote the imidization reaction of the polyamic acid to form a polyimide structure. The gel structure is solidified through low-temperature aging, and the solvent is removed by freeze-drying to generate a porous memory foam. The fiber sponge serves as a reinforcing skeleton to give the foam deformation memory function, and finally the memory foam is prepared.

[0010] The reaction equation for preparing memory foam is:

[0011]

[0012] S3, performing surface modification on the memory foam and post-processing to obtain a composite memory foam;

[0013] S4. Add memory foam, silica sol and saturated sodium hydroxide aqueous solution into a vacuum reactor. After evacuating the vacuum reactor, increase the temperature to 40-50° C., keep the temperature for reaction for 10-12 hours, and then perform post-processing to obtain a high-elasticity insole material.

[0014] The reaction principle for preparing high-elasticity insole materials is as follows: silica sol penetrates into the porous structure of memory foam through vacuum pumping under vacuum conditions. Saturated sodium hydroxide provides an alkaline environment, which promotes the hydrolysis and polycondensation reaction of silica sol to generate a siloxane network. At the same time, the organic metal framework in the composite memory foam chemically bonds with the silanol groups generated by the hydrolysis of silica sol through surface functional groups to form a cross-linked structure, ultimately obtaining a high-elasticity insole material.

[0015] Furthermore, in step S1, the ratio of the composite polystyrene to o-xylene is 2 g:8-10 g, and the air-jet spinning operation is as follows: the spinning solution is loaded into a syringe, extruded using a coaxial nozzle at a rate of 1-2 mL / h, the high-speed air flow velocity is 10-12 m / s, and the distance between the cage collector and the syringe needle is 30-50 cm. The post-processing includes: after the spinning is completed, the sponge material in the cage collector is transferred to a vacuum drying at a temperature of 60-80°C, and kept warm and dried to a constant weight to obtain a fiber sponge;

[0016] Furthermore, in step S2, the ratio of the fiber sponge, modified polyamic acid, N,N-dimethylformamide, acetic anhydride and triethylamine is 1-2 g: 3-4 g: 20-24 mL: 1.0-1.2 g: 0.3-0.5 g, and the post-processing includes: after the reaction is completed, aging the obtained gel in a refrigerator at a temperature of 5-8°C for 24 hours, transferring the material to a drying oven at a temperature of -70°C and freezing for 3 hours, and then transferring the material to a freeze dryer at a temperature of -80°C and a pressure of 0.8 bar, and freeze-drying for 60 hours to obtain a memory foam;

[0017] Furthermore, in step S4, the memory foam, silica sol and saturated sodium hydroxide aqueous solution are used in a ratio of 3-5 g:4-5 g:1-2 mL, and the post-processing includes: after the reaction is completed, transferring the material to a vacuum drying oven at a temperature of 60-80°C, and vacuum drying the material until the weight is constant to obtain a high-elasticity insole material.

[0018] Furthermore, in step S1, the method for preparing the composite polystyrene comprises the following steps:

[0019] A1. Add styrene, vinyl terephthalic acid, 3-butene-1-amine, and o-xylene to a reactor, stir at room temperature for 10-12 minutes, raise the temperature of the reactor to 70-80° C., add azobisisobutyronitrile to the reactor, keep the temperature for reaction for 40-60 minutes, and perform post-treatment to obtain modified polystyrene.

[0020] The reaction equation for preparing modified polystyrene is:

[0021]

[0022] The reaction principle for preparing modified polystyrene is as follows: under the promotion of heating and catalyst, the double bonds of styrene, vinyl terephthalic acid and 3-butene-1-amine are broken, and a free radical addition reaction occurs, ultimately preparing modified polystyrene.

[0023] A2. Add zirconium chloride, modified polystyrene, o-xylene and glacial acetic acid into an autoclave, stir at room temperature for 10-15 minutes, seal the autoclave and increase the temperature of the autoclave to 120-130° C., keep the temperature for reaction for 16-20 hours, and post-treat to obtain composite polystyrene.

[0024] The reaction principle for preparing composite polystyrene is: under the catalysis of acidity, high temperature and high pressure, the chromium ions of zirconium chloride and the carboxyl groups on the terephthalic acid structure undergo coordination reaction to form an organic metal framework structure.

[0025] Furthermore, in step A1, the amount ratio of styrene, vinyl terephthalic acid, 3-butene-1-amine, o-xylene and azobisisobutyronitrile is 4-5g:2-3g:1-2g:30-36mL:0.5-0.8g, and the post-treatment includes: after the reaction is completed, transferring the reaction solution to a vacuum dryer at a temperature of 60-80°C, and vacuum drying until no liquid is extracted to obtain modified polystyrene;

[0026] Furthermore, in step A2, the usage ratio of the zirconium chloride, modified polystyrene, o-xylene and glacial acetic acid is 1-2 g:7-9 g:60-80 mL:4-5 mL, and the post-treatment includes: after the reaction is completed, transferring the reaction liquid to a vacuum dryer at a temperature of 60-80°C, and vacuum drying until no liquid is extracted to obtain composite polystyrene.

[0027] Furthermore, in step S2, the preparation method of the modified polyamic acid is as follows: 1,3-propylenediamine and N,N-dimethylformamide are added to a reactor at a temperature of 0-5°C, and after stirring for 5-6 minutes, 4,4'-oxydiphthalic anhydride is added to the reactor in three times. After the addition is completed, the temperature of the reactor is increased to 30-50°C, and the reaction is carried out by keeping the temperature for 2-4 hours. Then, a calculated amount of a capping agent is added to the reactor, and the reaction is carried out by keeping the temperature for 10-20 minutes, and the modified polyamic acid is obtained by post-processing.

[0028] The reaction principle for preparing modified polyamic acid is as follows: at 0-5°C, the amino group of 1,3-propylenediamine and the anhydride group of 4,4'-oxydiphthalic anhydride undergo a ring-opening addition reaction to generate a polyamic acid main chain. After the reaction temperature rises to 30-50°C, chain growth is promoted, and a capping agent is added to react with the terminal functional groups to control the molecular weight and stabilize the structure to obtain modified polyamic acid.

[0029] The reaction equation for preparing modified polyamic acid is:

[0030]

[0031] Furthermore, the amount ratio of 1,3-propylenediamine, N,N-dimethylformamide and 4,4'-oxydiphthalic anhydride is 0.4-0.5g:10-12mL:2.4-2.8g, the end-capping agent is 2-aminoimidazole, and in the reaction, the 2-aminoimidazole is 0.8 times the molar amount of the anhydride group in the reaction system. The post-treatment includes: after the reaction is completed, transferring the reaction liquid to a vacuum dryer at a temperature of 60-80°C, and vacuum drying until no liquid is recovered to obtain modified polyamic acid.

[0032] Furthermore, in step S3, the surface modification operation includes the following steps:

[0033] B1. Add the memory foam and the modification liquid into an ultrasonic instrument, ultrasonicate for 30-40 minutes at room temperature, let it stand for 10-12 hours, and post-treat to obtain the modified memory foam;

[0034] B2. Add the modified memory foam and ethylene glycol to the reactor, introduce nitrogen protection, raise the temperature of the reactor to 50-70°C, keep warm and stir for 20-25 minutes, add triethylamine to the reactor, continue to keep warm and stir for 5-8 minutes, add bromobenzene dropwise to the reactor, continue to add dropwise for 1-2 hours, keep warm and stir for 3-4 hours, and post-treat to obtain the composite memory foam.

[0035] The reaction principle for preparing the composite memory foam is as follows: zinc nitrate hexahydrate is dissolved in methanol to form a modifying liquid, which reacts with the memory foam under ultrasonic action. The ultrasonic treatment promotes the coordination or adsorption of zinc ions with methylimidazole on the surface or inside the memory foam, thereby modifying the surface properties and pore structure of the foam to obtain the modified memory foam. The nitrogen atoms of the tertiary amines dispersed on the memory foam have lone pairs of electrons, which attack the carbon-bromine bond in bromobenzene, causing the bromine atoms to leave, generate quaternary ammonium cations, and simultaneously release bromide anions. During the reaction, triethylamine acts as an alkaline catalyst to adjust the pH of the system, promote nucleophilic attack, and ultimately form a stable quaternary ammonium salt structure to obtain the composite memory foam.

[0036] Furthermore, in step B1, the memory foam and the modifying liquid are used in a ratio of 1 g:10 mL, wherein the modifying liquid is a mixture of zinc nitrate hexahydrate and methanol in a ratio of 1-2 g:12 mL. Post-processing includes: after the reaction is completed, transferring the material to a vacuum drying oven at a temperature of 60-80° C. and vacuum drying the material until the weight is constant to obtain a modified memory foam;

[0037] Furthermore, in step B2, the modified memory foam, ethylene glycol, triethylamine and bromobenzene are used in an amount ratio of 3-4 g:20-24 mL:0.5-0.8 g:1-2 g, and the post-processing includes: after the reaction is completed, transferring the material to a vacuum drying oven at a temperature of 60-80°C, and vacuum drying the material until the weight is constant to obtain a composite memory foam.

[0038] The present invention also provides a shape memory molecule reinforced high elasticity insole material, which is prepared by a method for preparing a shape memory molecule reinforced high elasticity insole material.

[0039] The present invention has the following beneficial effects:

[0040] 1. The pore network of the high-elasticity insole material prepared by the present invention accommodates external forces through a deformation memory mechanism and quickly recovers its original shape after deformation. At the same time, the stretching ability of the molecular chain and the rigid support of the cross-linked network work together to ensure efficient elastic recovery. The organic metal framework is used as a skeleton to provide stable compressive resistance, which cooperates with the dynamic extension and retraction of the molecular chain to enhance the energy release efficiency after deformation. The coordination effect of the imidazole group and the metal ion forms local rigid points, which cooperates with the electrostatic interaction of the quaternary ammonium salt to optimize the balance of intermolecular forces and further improve the rebound stability. The siloxane network fills the pores through cross-linking and works together with the organic metal framework to form a composite structure with both flexibility and rigidity, which promotes energy transfer and recovery during compression and release. Finally, the microscopic pore structure generated by the low-temperature foaming process complements the macroscopic elastic network. Overall, through chemical bonding, physical structure synergy and process-induced micromorphological optimization, it is ensured that the material quickly recovers its initial shape after repeated pressure and exhibits excellent rebound performance.

[0041] 2. The quaternary ammonium salt cations in the high-elasticity insole material prepared by the present invention destroy the membrane structure through the strong interaction between its positive charge and the negative charge of the bacterial cell membrane, causing the bacterial contents to leak and die. At the same time, the porous network structure significantly increases the surface area of the material, enhances the contact efficiency of the quaternary ammonium salt with bacteria, thereby improving the bactericidal effect. The metal ions in the organic metal framework in the material cooperate with the chemical sterilization mechanism of the quaternary ammonium salt to jointly inhibit the growth and reproduction of bacteria. The coordination of the imidazole group and the zinc ion further strengthens the local antibacterial activity, complements the quaternary ammonium salt effect, and constructs a multi-level antibacterial defense line. The siloxane cross-linked network acts as a stable carrier and cooperates with the porous structure to extend the release cycle of the antibacterial component and maintain a long-term antibacterial effect. Finally, the chemical sterilization of the quaternary ammonium salt, the oxidative stress of the metal ions, the enhanced local activity of the imidazole group, and the physical synergy of the porous structure are utilized. Through the close cooperation of chemical and physical mechanisms, it is ensured that the material has efficient and lasting antibacterial performance, can effectively inhibit bacterial growth under various environments, and exhibits excellent antibacterial properties.

[0042] 3. The rigid skeleton provided by the organic metal framework in the high-elasticity insole material prepared by the present invention, and the coordination effect with the molecular chain enhances the deformation resistance of the overall structure. At the same time, the cross-linked network of modified polystyrene and modified polyamic acid forms a tight molecular connection through chemical bonding, which synergistically improves the fracture resistance during stretching; the porous fiber sponge structure accommodates external forces through the deformation of the pores during stretching, which complements the elastic recovery ability of the cross-linked network, effectively disperses stress, and prevents local failure of the material. The siloxane cross-linked network further enhances the toughness of the material, and works together with the organic metal framework and the porous structure to form a composite system combining flexibility and rigidity, which can maintain structural integrity under tensile stress. The micropore structure generated by the low-temperature foaming process synergizes with the macro network to give the material excellent ductility and resilience, ensuring that it can quickly recover to its original shape after stretching, so that the material exhibits excellent performance and durability when subjected to tensile stress. DETAILED DESCRIPTION

[0043] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] Example 1

[0045] This embodiment provides a method for preparing a fiber sponge for preparing a high-elasticity shoe insole material reinforced with shape memory molecules, comprising the following steps:

[0046] Step 1: Preparation of modified polystyrene

[0047] Weigh: 40.0 g of styrene, 20.0 g of vinyl terephthalic acid, 10.0 g of 3-butene-1-amine and 300.0 mL of o-xylene are added to a reactor, stirred at room temperature for 12 minutes, and then the temperature of the reactor is raised to 70°C and 5.0 g of azobisisobutyronitrile is added to the reactor. After the reaction is kept warm for 40 minutes, after the reaction is completed, the reaction solution is transferred to a vacuum dryer at a temperature of 60°C and vacuum dried until no liquid is extracted to obtain modified polystyrene.

[0048] Step 2: Preparation of composite polystyrene

[0049] Weigh: 10.0 g of zirconium chloride, 70.0 g of modified polystyrene, 600.0 mL of o-xylene and 40.0 mL of glacial acetic acid are added to a high-pressure reactor. After stirring at room temperature for 10 minutes, the high-pressure reactor is sealed and the temperature of the high-pressure reactor is increased to 120°C. The reaction is kept warm for 16 hours. After the reaction is completed, the reaction liquid is transferred to a vacuum dryer at a temperature of 60°C and vacuum dried until no liquid is extracted to obtain composite polystyrene.

[0050] Step 3: Preparation of fiber sponge

[0051] Weigh: 20.0 g of composite polystyrene and 80.0 g of o-xylene are mixed to obtain a spinning solution, which is loaded into a syringe and extruded using a coaxial nozzle at a rate of 1.0 mL / h. The high-speed air flow velocity is 10 m / s, and the distance between the cage collector and the syringe needle is 30 cm. After spinning is completed, the sponge material in the cage collector is transferred to a vacuum dryer at a temperature of 60°C, kept warm and dried to constant weight to obtain a fiber sponge.

[0052] Example 2

[0053] This embodiment provides a method for preparing a fiber sponge for preparing a high-elasticity shoe insole material reinforced with shape memory molecules, comprising the following steps:

[0054] Step 1: Preparation of modified polystyrene

[0055] Weigh: 50.0 g of styrene, 30.0 g of vinyl terephthalic acid, 20.0 g of 3-butene-1-amine and 360.0 mL of o-xylene are added to a reactor, stirred at room temperature for 12 minutes, and then the temperature of the reactor is raised to 80° C. and 8.0 g of azobisisobutyronitrile is added to the reactor. After the reaction is kept warm for 60 minutes, after the reaction is completed, the reaction liquid is transferred to a vacuum dryer at a temperature of 80° C. and vacuum dried until no liquid is extracted to obtain modified polystyrene.

[0056] Step 2: Preparation of composite polystyrene

[0057] Weigh: 20.0g zirconium chloride, 90.0g modified polystyrene, 800.0mL o-xylene and 50.0mL glacial acetic acid are added to a high-pressure reactor, stirred at room temperature for 15 minutes, sealed the high-pressure reactor and raised the temperature of the high-pressure reactor to 130°C, and kept warm for 20 hours. After the reaction is completed, the reaction liquid is transferred to a vacuum dryer at a temperature of 80°C and vacuum dried until no liquid is extracted to obtain composite polystyrene.

[0058] Step 3: Preparation of fiber sponge

[0059] Weigh: 20.0 g of composite polystyrene and 100.0 g of o-xylene are mixed to obtain a spinning solution, which is loaded into a syringe and extruded using a coaxial nozzle at a rate of 20.0 mL / h. The high-speed air flow velocity is 12 m / s, and the distance between the cage collector and the syringe needle is 50 cm. After spinning is completed, the sponge material in the cage collector is transferred to a vacuum dryer at a temperature of 80°C, and kept warm and dried to constant weight to obtain a fiber sponge.

[0060] Example 3

[0061] This embodiment provides a method for preparing a fiber sponge for preparing a high-elasticity shoe insole material reinforced with shape memory molecules, comprising the following steps:

[0062] Step 1: Preparation of modified polystyrene

[0063] Weigh: 50.0 g of styrene, 30.0 g of vinyl terephthalic acid, 20.0 g of 3-butene-1-amine and 360.0 mL of o-xylene are added to a reactor, stirred at room temperature for 12 minutes, and then the temperature of the reactor is raised to 80° C. and 8.0 g of azobisisobutyronitrile is added to the reactor. After the reaction is kept warm for 60 minutes, after the reaction is completed, the reaction liquid is transferred to a vacuum dryer at a temperature of 80° C. and vacuum dried until no liquid is extracted to obtain modified polystyrene.

[0064] Step 2: Preparation of composite polystyrene

[0065] Weigh: 16.0g zirconium chloride, 80.0g modified polystyrene, 720.0mL o-xylene and 42.0mL glacial acetic acid are added to a high-pressure reactor, stirred at room temperature for 12 minutes, and then the high-pressure reactor is sealed and the temperature of the high-pressure reactor is increased to 120°C. The reaction is kept warm for 18 hours. After the reaction is completed, the reaction liquid is transferred to a vacuum dryer at a temperature of 70°C and vacuum dried until no liquid is extracted to obtain composite polystyrene.

[0066] Step 3: Preparation of fiber sponge

[0067] Weigh: 20.0 g of composite polystyrene and 100.0 g of o-xylene are mixed to obtain a spinning solution, which is loaded into a syringe and extruded using a coaxial nozzle at a rate of 1.6 mL / h. The high-speed air flow velocity is 10 m / s, and the distance between the cage collector and the syringe needle is 40 cm. After spinning is completed, the sponge material in the cage collector is transferred to a vacuum dryer at a temperature of 70°C, kept warm and dried to constant weight to obtain a fiber sponge.

[0068] Example 4

[0069] This embodiment provides a method for preparing a memory foam for use in preparing a high-elasticity insole material reinforced with shape memory molecules, comprising the following steps:

[0070] Step I: Preparation of modified polyamic acid

[0071] Weigh: 4.0g1,3-propylenediamine and 100.0mLN,N-dimethylformamide are added to a reactor at a temperature of 0°C, and stirred for 5 minutes. Then, 24.0g4,4'-oxydiphthalic anhydride is added to the reactor in three times. After the addition is completed, the temperature of the reactor is raised to 30°C, and the reaction is kept warm for 2 hours. Then, 0.8 times the molar amount of 2-aminoimidazole in the reaction system of the anhydride group in the reactor is added to the reactor, and the reaction is kept warm for 10 minutes. After the reaction is completed, the reaction liquid is transferred to a vacuum dryer at a temperature of 60°C and vacuum dried until no liquid is extracted to obtain modified polyamic acid.

[0072] Step II: Preparation of memory foam

[0073] Weigh: 20.0 g of the fiber sponge prepared in Example 1, 30.0 g of modified polyamic acid and 200.0 mL of N,N-dimethylformamide were added to the reactor, the reactor temperature was lowered to 0°C, and the reaction was kept warm for 20 minutes. The temperature of the vacuum reactor was raised to 70°C and 10.0 g of acetic anhydride and 3.0 g of triethylamine were added thereto, and the reaction was kept warm for 10 minutes. After the reaction was completed, the obtained gel was aged at 5°C in the refrigerator for 24 hours, and then the material was transferred to a drying oven at a temperature of -70°C and frozen for 3 hours. The material was then transferred to a freeze dryer at a temperature of -80°C and a pressure of 0.8 bar, and freeze-dried for 60 hours to obtain memory foam.

[0074] Example 5

[0075] This embodiment provides a method for preparing a memory foam for use in preparing a high-elasticity insole material reinforced with shape memory molecules, comprising the following steps:

[0076] Step I: Preparation of modified polyamic acid

[0077] Weigh: 5.0g1,3-propylenediamine and 120.0mLN,N-dimethylformamide are added to a reactor at a temperature of 5°C, and stirred for 6 minutes. Then, 28.0g4,4'-oxydiphthalic anhydride is added to the reactor in three times. After the addition is completed, the temperature of the reactor is raised to 50°C, and the reaction is kept warm for 4 hours. Then, 0.8 times the molar amount of 2-aminoimidazole in the reaction system of the anhydride group in the reactor is added to the reactor, and the reaction is kept warm for 20 minutes. After the reaction is completed, the reaction liquid is transferred to a vacuum dryer at a temperature of 80°C and vacuum dried until no liquid is extracted to obtain modified polyamic acid.

[0078] Step II: Preparation of memory foam

[0079] Weigh: 20.0 g of the fiber sponge prepared in Example 2, 40.0 g of modified polyamic acid and 240.0 mL of N,N-dimethylformamide were added to the reactor, the reactor temperature was lowered to 5 ° C, and the reaction was kept warm for 30 minutes. The temperature of the vacuum reactor was raised to 80 ° C and 12.0 g of acetic anhydride and 5.0 g of triethylamine were added thereto, and the reaction was kept warm for 20 minutes. After the reaction was completed, the obtained gel was aged at 8 ° C in the refrigerator for 24 hours, and then the material was transferred to a drying oven at a temperature of -70 ° C and frozen for 3 hours. The material was then transferred to a freeze dryer at a temperature of -80 ° C and a pressure of 0.8 bar, and freeze-dried for 60 hours to obtain memory foam.

[0080] Example 6

[0081] This embodiment provides a method for preparing a memory foam for use in preparing a high-elasticity insole material reinforced with shape memory molecules, comprising the following steps:

[0082] Step I: Preparation of modified polyamic acid

[0083] Weigh: 4.2g 1,3-propylenediamine and 120.0mL N,N-dimethylformamide are added to a reactor at a temperature of 3°C, and stirred for 6 minutes. Then, 27.0g 4,4'-oxydiphthalic anhydride is added to the reactor in three times. After the addition is completed, the temperature of the reactor is raised to 40°C, and the reaction is kept warm for 3 hours. Then, 0.8 times the molar amount of 2-aminoimidazole in the reaction system of the anhydride group in the reactor is added to the reactor, and the reaction is kept warm for 15 minutes. After the reaction is completed, the reaction liquid is transferred to a vacuum dryer at a temperature of 70°C and vacuum dried until no liquid is extracted to obtain modified polyamic acid.

[0084] Step II: Preparation of memory foam

[0085] Weigh: 20.0 g of the fiber sponge prepared in Example 3, 36.0 g of modified polyamic acid and 210.0 mL of N,N-dimethylformamide were added to the reactor, the reactor temperature was lowered to 3 ° C, and the reaction was kept warm for 24 minutes. The temperature of the vacuum reactor was raised to 72 ° C and 12.0 g of acetic anhydride and 4.0 g of triethylamine were added thereto, and the reaction was kept warm for 16 minutes. After the reaction was completed, the obtained gel was aged at 6 ° C in the refrigerator for 24 hours, and then the material was transferred to a drying oven at a temperature of -70 ° C and frozen for 3 hours. The material was then transferred to a freeze dryer at a temperature of -80 ° C and a pressure of 0.8 bar, and freeze-dried for 60 hours to obtain memory foam.

[0086] Example 7

[0087] This embodiment provides a method for preparing a high-elasticity insole material reinforced with shape memory molecules, comprising the following steps:

[0088] Step (i) Preparation of modified memory foam

[0089] Weigh 10.0 g of zinc nitrate hexahydrate and mix with 120.0 mL of methanol to obtain the modification solution.

[0090] Weigh: 10.0 g of the memory foam prepared in Example 4 and 100.0 mL of the modification liquid were added to an ultrasonic instrument, ultrasonicated at room temperature for 30 minutes, and then allowed to stand for 10 hours. After the reaction was completed, the material was transferred to a vacuum drying oven at a temperature of 60°C and vacuum dried to a constant weight to obtain a modified memory foam.

[0091] Step (ii) Preparation of composite memory foam

[0092] Weigh: 3.0 g of modified memory foam and 20.0 mL of ethylene glycol were added to the reactor. After nitrogen protection, the temperature of the reactor was raised to 50°C. After stirring for 20 minutes, 0.5 g of triethylamine was added to the reactor. After continuing to stir for 5-8 minutes, 1.0 g of bromobenzene was added dropwise to the reactor. The addition was continued for 1 hour. The reaction was stirred for 3 hours. After the reaction was completed, the material was transferred to a vacuum drying oven at 60°C and vacuum dried until the material had a constant weight to obtain a composite memory foam.

[0093] Step (iii) preparing high elasticity insole material

[0094] Weigh: 3.0 g of memory foam, 4.0 g of silica sol and 1.0 mL of saturated sodium hydroxide aqueous solution are added to a vacuum reactor. After the vacuum reactor is evacuated, the temperature is raised to 40°C and the reaction is kept warm for 10 hours. After the reaction is completed, the material is transferred to a vacuum drying oven at a temperature of 60°C and vacuum dried until the material has a constant weight to obtain a high-elasticity insole material.

[0095] Example 8

[0096] This embodiment provides a method for preparing a high-elasticity insole material reinforced with shape memory molecules, comprising the following steps:

[0097] Step (i) Preparation of modified memory foam

[0098] Weigh 20.0 g of zinc nitrate hexahydrate and mix with 12.0 mL of methanol to obtain the modification solution.

[0099] Weigh: 10.0 g of the memory foam prepared in Example 5 and 100.0 mL of the modification liquid were added to an ultrasonic instrument, ultrasonicated at room temperature for 40 min, and allowed to stand for 10 h. After the reaction was completed, the material was transferred to a vacuum drying oven at 80° C. and vacuum dried to a constant weight to obtain a modified memory foam.

[0100] Step (ii) Preparation of composite memory foam

[0101] Weigh: 4.0 g of modified memory foam and 24.0 mL of ethylene glycol were added to the reactor. After nitrogen protection, the temperature of the reactor was raised to 70°C. After stirring for 25 minutes, 0.8 g of triethylamine was added to the reactor. After continuing to stir for 8 minutes, 2.0 g of bromobenzene was added dropwise to the reactor. The addition was continued for 2 hours, and the mixture was stirred for 4 hours. After the reaction was completed, the material was transferred to a vacuum drying oven at 80°C and vacuum dried until the material had a constant weight to obtain a composite memory foam.

[0102] Step (iii) preparing high elasticity insole material

[0103] Weigh: 5.0 g of memory foam, 5.0 g of silica sol and 2.0 mL of saturated sodium hydroxide aqueous solution are added to a vacuum reactor. After the vacuum reactor is evacuated, the temperature is raised to 50°C and the reaction is kept warm for 12 hours. After the reaction is completed, the material is transferred to a vacuum drying oven at 80°C and vacuum dried until the material has a constant weight to obtain a high-elasticity insole material.

[0104] Example 9

[0105] This embodiment provides a method for preparing a high-elasticity insole material reinforced with shape memory molecules, comprising the following steps:

[0106] Step (i) Preparation of modified memory foam

[0107] Weigh 16.0 g of zinc nitrate hexahydrate and mix with 120.0 mL of methanol to obtain the modification solution.

[0108] Weigh: 10.0 g of the memory foam prepared in Example 6 and 100.0 mL of the modification liquid were added to an ultrasonic instrument. After ultrasonication at room temperature for 35 minutes, the material was allowed to stand for 12 hours. After the reaction was completed, the material was transferred to a vacuum drying oven at a temperature of 70°C and vacuum dried to a constant weight to obtain a modified memory foam.

[0109] Step (ii) Preparation of composite memory foam

[0110] Weigh: 4.0 g of modified memory foam and 21.0 mL of ethylene glycol were added to the reactor. After nitrogen protection, the temperature of the reactor was raised to 60°C. After stirring for 21 minutes, 0.6 g of triethylamine was added to the reactor. After stirring for 6 minutes, 1.0 g of bromobenzene was added dropwise to the reactor. The addition was continued for 2 hours. The reaction was stirred for 4 hours. After the reaction was completed, the material was transferred to a vacuum drying oven at 70°C and vacuum dried until the material had a constant weight to obtain a composite memory foam.

[0111] Step (iii) preparing high elasticity insole material

[0112] Weigh: 4.0 g of memory foam, 5.0 g of silica sol and 2.0 mL of saturated sodium hydroxide aqueous solution are added to a vacuum reactor. After the vacuum reactor is evacuated, the temperature is raised to 45°C and the reaction is kept warm for 11 hours. After the reaction is completed, the material is transferred to a vacuum drying oven at a temperature of 70°C and vacuum dried until the material has a constant weight to obtain a high-elasticity insole material.

[0113] Comparative Example 1

[0114] The difference between this comparative example and Example 9 is that the modified memory foam used in step (i) is a fiber sponge used in the preparation process, and step (ii) is omitted in the preparation process.

[0115] Comparative Example 2

[0116] The difference between this comparative example and Example 9 is that the modified memory foam used in step (i) does not use fiber sponge during the preparation process.

[0117] Comparative Example 3

[0118] The difference between this comparative example and Example 9 is that step (ii) is omitted.

[0119] Performance testing:

[0120] The rebound rates of the high-elasticity insole materials prepared in Examples 7-9 and Comparative Examples 1-3 were measured with reference to the standard HG / T 4993-2016 “Test method for rebound resilience of microporous materials for footwear”;

[0121] With reference to the standard GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Oscillation method", the antibacterial rate of the high-elasticity insole materials prepared in Examples 7-9 and Comparative Examples 1-3 was tested, wherein the selected bacterial species were Staphylococcus aureus and Candida albicans, respectively;

[0122] The tensile strength and elongation at break of the high elasticity insole materials prepared in Examples 7-9 and Comparative Examples 1-3 were tested with reference to the standard GB / T 6344-2008 “Determination of tensile strength and elongation at break of flexible foam polymeric materials”. Specific data are shown in Table 1.

[0123] Table 1 - Performance test data of each sample

[0124]

[0125] Data Analysis:

[0126] After comparing and analyzing the data in Table 1, it can be found that the high-elasticity insole material prepared by the present invention has a rebound rate of 96.4%, an antibacterial rate of Staphylococcus aureus of 99.1%, an antibacterial rate of Candida albicans of 99.3%, a tensile strength of 13.2 MPa, and an elongation at break of 335%, all of which are better than the comparative example;

[0127] After comparing and analyzing the data in Table 1, it can be found that the rebound rate of the high elastic insole materials prepared in Comparative Examples 1-3 is significantly lower than that of the high elastic insole material prepared in Example 12, indicating that:

[0128] In Comparative Example 1, the fiber sponge was not introduced into the organic metal framework during the preparation process, lacking rigid support, resulting in a decrease in deformation recovery ability. Although the porous structure still exists, the lack of the synergistic effect of the framework and the cross-linked network reduces the stress dispersion and elastic recovery efficiency, and the rebound performance is significantly weakened.

[0129] Comparative Example 2 eliminated the fiber sponge and directly lost the support of the porous structure. The deformation memory and stress dispersion capabilities were completely lost. The material relied solely on the molecular chain to recover the deformation. The synergistic effect of the pore network and cross-linked structure was lacking, resulting in extremely poor rebound performance.

[0130] In Comparative Example 3, no quaternary ammonium salt was formed, the intermolecular force was weakened, and the elastic recovery efficiency of the cross-linked network was reduced. Although supported by the porous structure of the fiber sponge, the synergistic effect of the quaternary ammonium salt and the imidazole group was lacking, and the rebound performance was slightly reduced.

[0131] After comparing and analyzing the data in Table 1, it can be found that the antibacterial properties of the high elasticity insole materials prepared in Comparative Examples 1-3 are significantly lower than those of the high elasticity insole materials prepared in Example 12, indicating that:

[0132] The fiber sponge of Comparative Example 1 was not modified by zirconium chloride, lacked zinc ion coordination, and had reduced antibacterial activity. Although the porous structure increased the surface area, the absence of oxidative stress from metal ions did not enhance the bactericidal effect of the quaternary ammonium salt, resulting in decreased antibacterial performance.

[0133] Comparative Example 2: The fiber-free sponge has a porous structure that disappears, a surface area that is greatly reduced, and a sharp decrease in the contact opportunities between the quaternary ammonium salt and zinc ions and bacteria. Furthermore, the antibacterial components cannot be effectively distributed, resulting in a significant decrease in bactericidal efficiency and durability, and extremely weak antibacterial performance.

[0134] Comparative Example 3 did not generate quaternary ammonium salt, lost the positive charge bactericidal mechanism, and greatly weakened the antibacterial ability. Although there was a coordination effect between zinc ions and imidazole groups, there was no chemical bactericidal synergy of quaternary ammonium salt, and the antibacterial performance was significantly reduced.

[0135] After comparing and analyzing the data in Table 1, it can be found that the tensile strength of the high elastic insole materials prepared in Comparative Examples 1-3 is significantly lower than that of the high elastic insole material prepared in Example 12, indicating that:

[0136] The fiber sponge of Comparative Example 1 lacks the rigid support of the organic metal framework and the strength of the cross-linked network is insufficient, which weakens the stress dispersion ability of the material during stretching, makes the molecular chain easily broken, and significantly reduces the tensile strength.

[0137] In Comparative Example 2, after the fiber sponge was removed, the material lost its supporting structure and the stress breaking ability. Although the cross-linked network existed, the synergistic support of the supporting structure made it easy to break when stretched, and the tensile strength was the worst.

[0138] In comparative example 3, the quaternary ammonium salt is missing, the intermolecular force is weakened, and the stability of the cross-linked network is reduced. Although the porous structure of the fiber sponge still provides a certain stress dispersion, the overall tensile strength is slightly reduced and the tensile resistance is slightly weaker.

[0139] Finally, the rebound performance of the high-elasticity shoe-pad material prepared by the present invention depends on the deformation accommodation capacity of the porous fiber sponge and the rigid support of the organic metal framework, combined with the toughness cross-linking of the siloxane network. If there is no porous structure or framework support, elastic recovery will significantly decrease; antibacterial performance relies on the positive charge bactericidal effect of quaternary ammonium salt and the oxidative stress of zinc ions, assisted by the local activity of imidazole groups. If there is a lack of quaternization or metal modification, the bactericidal efficiency will be greatly weakened; tensile strength benefits from the molecular connection of the cross-linked network and the rigidity enhancement of the organic metal framework, combined with the toughness of the siloxane network. If there is no framework or cross-linking, the material's fracture resistance will be insufficient. Compression resistance, wear resistance and breathability rely on the synergistic protection of porous structure and siloxane. If one is missing, structural stability will decrease. Aging resistance, hydrophobicity and softness require the comprehensive optimization of imidazole groups, quaternary ammonium salts and low-temperature foaming process. Each material and modification step complement each other to ensure that performance is comprehensively improved.

[0140] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a high-elasticity insole material reinforced with shape memory molecules, characterized in that: The following steps are involved: S1. Mixing composite polystyrene and o-xylene to obtain a spinning solution, performing air-spinning on the spinning solution, and post-treating to obtain a fiber sponge; S2, adding fiber sponge, modified polyamic acid and N,N-dimethylformamide into a reactor, lowering the temperature of the reactor to 0-5°C, keeping the temperature for reaction for 20-30 minutes, raising the temperature of the vacuum reactor to 70-80°C, adding acetic anhydride and triethylamine, keeping the temperature for reaction for 10-20 minutes, and post-processing to obtain memory foam; S3, performing surface modification on the memory foam and post-processing to obtain a composite memory foam; S4. Add memory foam, silica sol and saturated sodium hydroxide aqueous solution into a vacuum reactor. After evacuating the vacuum reactor, increase the temperature to 40-50° C., keep the temperature for reaction for 10-12 hours, and then perform post-processing to obtain a high-elasticity insole material.

2. The method for preparing the shape memory molecule reinforced high elasticity insole material according to claim 1, characterized in that: In step S1, the amount ratio of the composite polystyrene and o-xylene is 2g:8-10g, and the airflow spinning operation is as follows: the spinning solution is loaded into a syringe, and extruded at a rate of 1-2mL / h using a coaxial nozzle, the high-speed air flow speed is 10-12m / s, and the distance between the cage collector and the syringe needle is 30-50cm; in step S2, the amount ratio of the fiber sponge, modified polyamic acid, N,N-dimethylformamide, acetic anhydride and triethylamine is 1-2g:3-4g:20-24mL:1.0-1.2g:0.3-0.5g; in step S4, the amount ratio of the memory foam, silica sol and saturated sodium hydroxide aqueous solution is 3-5g:4-5g:1-2mL.

3. The method for preparing the shape memory molecule reinforced high elasticity insole material according to claim 1, characterized in that: In step S1, the method for preparing the composite polystyrene comprises the following steps: A1. Add styrene, vinyl terephthalic acid, 3-butene-1-amine, and o-xylene to a reactor, stir at room temperature for 10-12 minutes, raise the temperature of the reactor to 70-80° C., add azobisisobutyronitrile to the reactor, keep the temperature for reaction for 40-60 minutes, and perform post-treatment to obtain modified polystyrene. A2. Add zirconium chloride, modified polystyrene, o-xylene and glacial acetic acid into an autoclave, stir at room temperature for 10-15 minutes, seal the autoclave and increase the temperature of the autoclave to 120-130° C., keep the temperature for reaction for 16-20 hours, and post-treat to obtain composite polystyrene.

4. The method for preparing the shape memory molecule reinforced high elasticity insole material according to claim 3, characterized in that: In step A1, the amount ratio of styrene, vinyl terephthalic acid, 3-butene-1-amine, o-xylene and azobisisobutyronitrile is 4-5g:2-3g:1-2g:30-36mL:0.5-0.8g; in step A2, the amount ratio of zirconium chloride, modified polystyrene, o-xylene and glacial acetic acid is 1-2g:7-9g:60-80mL:4-5mL.

5. The method for preparing the shape memory molecule reinforced high elasticity insole material according to claim 1, characterized in that: In step S2, the preparation method of the modified polyamic acid is as follows: 1,3-propylenediamine and N,N-dimethylformamide are added to a reactor at a temperature of 0-5°C, and after stirring for 5-6 minutes, 4,4'-oxydiphthalic anhydride is added to the reactor in three times. After the addition is completed, the temperature of the reactor is increased to 30-50°C, and the reaction is carried out by keeping the temperature for 2-4 hours. Then, a calculated amount of a capping agent is added to the reactor, and the reaction is carried out by keeping the temperature for 10-20 minutes. The modified polyamic acid is obtained by post-processing.

6. The method for preparing the shape memory molecule reinforced high elasticity insole material according to claim 5, characterized in that: The usage ratio of 1,3-propylenediamine, N,N-dimethylformamide and 4,4'-oxydiphthalic anhydride is 0.4-0.5g:10-12mL:2.4-2.8g. The end-capping agent is 2-aminoimidazole. In the reaction, the molar amount of 2-aminoimidazole is 0.8 times of the anhydride group in the reaction system.

7. The method for preparing the shape memory molecule reinforced high elasticity insole material according to claim 1, characterized in that: In step S3, the surface modification operation includes the following steps: B1. Add the memory foam and the modification liquid into an ultrasonic instrument, ultrasonicate for 30-40 minutes at room temperature, let it stand for 10-12 hours, and post-treat to obtain the modified memory foam; B2. Add the modified memory foam and ethylene glycol to the reactor, introduce nitrogen protection, raise the temperature of the reactor to 50-70°C, keep warm and stir for 20-25 minutes, add triethylamine to the reactor, continue to keep warm and stir for 5-8 minutes, add bromobenzene dropwise to the reactor, continue to add dropwise for 1-2 hours, keep warm and stir for 3-4 hours, and post-treat to obtain the composite memory foam.

8. The method for preparing the shape memory molecule reinforced high elasticity insole material according to claim 7, characterized in that: In step B1, the memory foam and the modifying liquid are used in a ratio of 1 g:10 mL, wherein the modifying liquid is a mixture of zinc nitrate hexahydrate and methanol in a ratio of 1-2 g:12 mL; in step B2, the modified memory foam, ethylene glycol, triethylamine, and bromobenzene are used in a ratio of 3-4 g:20-24 mL:0.5-0.8 g:1-2 g.

9. High elasticity insole material reinforced with shape memory molecules, characterized in that: The shape memory molecule reinforced high elasticity insole material is prepared by the preparation method of the shape memory molecule reinforced high elasticity insole material according to any one of claims 1 to 8.

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