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Synergetic effect between curing reaction and CO2 diffusion for microcellular epoxy foam preparation in supercritical CO2
The Journal of Supercritical Fluids ( IF 3.4 ) Pub Date : 2021-10-05 , DOI: 10.1016/j.supflu.2021.105424
Yijie Ling 1 , Shun Yao 1 , Yichong Chen 1 , DongDong Hu 2 , Zhenhao Xi 1 , Ling Zhao 1, 3
Affiliation  

Directly rapid depressurization foaming process has been successfully applied to prepare microcellular epoxy foams using supercritical CO2 as blowing agent. It is found that both curing reaction and CO2 diffusion are crucial for controlling cell morphology. For epoxy of tetraglycidyl-4,4′-diaminodiphenyl-methane (TGDDM) and 4,4-diaminodiphenylsulfone (4,4-DDS) system, the experimental and molecular simulation results displayed that higher CO2 pressure always promotes curing reaction, and CO2 diffusion is more sensitive to pressure at low curing degree, while limited by high curing degree. The foaming experimental results showed that there existed a suitable curing degree range, in which both unsaturated CO2 concentration and curing degree contribute to good cell structure. Higher CO2 pressure can broaden this foamable window. The microcellular epoxy foam with an average cell diameter of 14.6 µm and cell density over 109 cells/cm3 as well as volume expansion ratio of 14.5 has been obtained at 85% curing degree under 22 MPa CO2 pressure.



中文翻译:

超临界 CO2 环境下微孔环氧泡沫制备固化反应与 CO2 扩散的协同效应

直接快速减压发泡工艺已成功应用于以超临界CO 2为发泡剂制备微孔环氧树脂泡沫。发现固化反应和CO 2扩散对于控制细胞形态是至关重要的。对于四缩水甘油基-4,4'-二氨基二苯甲烷(TGDDM)和4,4-二氨基二苯砜(4,4-DDS)体系的环氧树脂,实验和分子模拟结果表明,较高的CO 2压力总是促进固化反应,而CO 2扩散在低固化度时对压力更敏感,而受高固化度限制。发泡实验结果表明存在合适的固化度范围,其中不饱和CO 2浓度和固化程度有助于形成良好的泡孔结构。更高的 CO 2压力可以拓宽这个可发泡的窗口。在22 MPa CO 2压力下以85%固化度获得平均泡孔直径为14.6μm、泡孔密度超过10 9 个/cm 3以及体积膨胀比为14.5的微孔环氧泡沫。

更新日期:2021-10-21
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