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Preparation method of ethylene-vinyl acetate copolymer porous shape memory material

A vinyl acetate copolymer and vinyl acetate copolymerization technology, applied in the field of polymer materials, can solve the problems of complex process flow, increase production cost, uneven material pore diameter, etc., achieve simple and feasible process process, avoid collapse and damage, and mild process conditions Effect

Active Publication Date: 2021-08-17
ZHEJIANG SCI-TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the existing preparation processes of EVA porous shape memory materials are mostly based on physical / chemical foaming methods, which require complex mixing and molding equipment, high processing temperature and molding pressure, and the obtained materials have uneven pore sizes.
EVA porous materials with uniform pore size can be obtained by using the sacrificial template method, but the use of template raw materials significantly increases the production cost and limits its large-scale production, and the high temperature of the existing cross-linking process will melt EVA and destroy the original open-pore structure
Therefore, the existing preparation process not only has unfavorable factors such as high equipment / raw material requirements and complex process flow, but also cannot affect the final product quality of the material, which limits the large-scale production and commercial application of the material.

Method used

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  • Preparation method of ethylene-vinyl acetate copolymer porous shape memory material
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preparation example Construction

[0032] A simple and easy method for preparing EVA porous shape memory material, it comprises the following steps:

[0033] Step 1, dissolve ethylene-vinyl acetate copolymer (EVA) with a vinyl acetate content of 18%-32% in a mixed solvent of toluene and n-propanol (3:1) at 70°C to obtain a concentration of 100-180mg / mL of EVA solution;

[0034] Step 2, transfer the above EVA solution to the mold, and conduct a low-temperature (0-50°C) water bath for 0.5-1 hour to induce phase separation to obtain a porous EVA material;

[0035] Step 3: Transfer the above porous EVA material to an acetone solution (concentration: 0.01-0.1g / mL) dissolved with benzoyl peroxide, soak for 3 hours, heat to 70°C and react for 2-6 hours to complete cross-linking , to obtain a cross-linked product;

[0036] In step 4, the above-mentioned cross-linked product is washed and dried under reduced pressure to prepare an EVA porous shape memory material.

[0037] The mass fraction of vinyl acetate in the e...

Embodiment 1

[0040] Step 1, dissolve the EVA (Elvax460, DuPont, USA) pellets with a vinyl acetate content of 18% in a mixed solvent of toluene and n-propanol (3:1) at 70°C to obtain an EVA solution with a concentration of 180mg / mL .

[0041] Step 2, the above solution was transferred to a cylindrical mold, and placed in a low-temperature water bath at 45° C. for 0.5 hour to induce phase separation to obtain a porous EVA material.

[0042] Step 3: Transfer the above EVA material to an acetone solution (concentration: 0.05g / mL) dissolved with benzoyl peroxide, soak for 3 hours, heat to 70°C and react for 5 hours to complete the cross-linking.

[0043] In step 4, the cross-linked porous EVA is taken out, washed with ethanol, and dried under reduced pressure at room temperature to obtain the EVA porous shape memory material.

Embodiment 2

[0045] Step 1, dissolve EVA (Elvax460, DuPont, USA) pellets with 18% vinyl acetate content in a mixed solvent of toluene and n-propanol (3:1) at 70°C to obtain concentrations of 120 mg / mL and 100 mg / mL mL of EVA solution.

[0046] Step 2, the above solution was transferred to a cylindrical mold, and placed in a low-temperature water bath at 45° C. for 0.5 hour to induce phase separation to obtain a porous EVA material.

[0047] Step 3: Transfer the above-mentioned porous EVA material to an acetone solution (concentration: 0.05 g / mL) dissolved with benzoyl peroxide, soak for 3 hours, heat to 70°C and react for 5 hours to complete cross-linking.

[0048]In step 4, the cross-linked porous EVA is taken out, washed with ethanol, and dried under reduced pressure at normal temperature to prepare the EVA porous shape memory material.

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Abstract

The invention relates to the technical field of high polymer materials, in particular to a preparation method of an ethylene-vinyl acetate copolymer porous shape memory material. The method comprises the following steps: firstly, taking an ethylene-vinyl acetate copolymer as a raw material, dissolving the ethylene-vinyl acetate copolymer in a mixed solvent of toluene and n-propanol, carrying out cooling induced thermally induced phase separation to obtain porous EVA with uniform pore diameters, then immersing the porous EVA into an acetone solution of benzoyl peroxide, and carrying out heating crosslinking, washing and drying to obtain the porous shape memory polymer material. The preparation process of the method is green and environment-friendly, the related solvents can be recycled, the cost of the raw materials is low, the pore diameter of the prepared material is uniform, simple and easy to adjust, and the porous shape memory polymer material with uniform pore diameter can be effectively prepared.

Description

technical field [0001] The invention relates to the technical field of polymer materials, in particular to a preparation method of an ethylene-vinyl acetate copolymer porous shape memory material. Background technique [0002] Porous shape memory polymers are a class of smart polymer materials. This type of polymer material has superior characteristics such as large specific surface area, high porosity, and low density. At the same time, it can realize the shape fixation and spontaneous recovery of the material by responding to external stimuli (such as light, heat, electricity, magnetism, pH changes, etc.). This process is also accompanied by the flexible adjustment of application characteristics such as internal pore structure and compression performance. This makes such materials have good application potential in the fields of adsorption / separation, intelligent control of surface catalysis, and intelligent design of ergonomic structures. [0003] At present, in the pre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/40C08L23/08
CPCC08J9/40C08J2323/08
Inventor 钱晨叶杰克潘陈浩董余兵傅雅琴
Owner ZHEJIANG SCI-TECH UNIV
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