热致相分离法制备乙烯-三氟氯乙烯共聚物微孔膜

通过热致相分离法制备了乙烯-三氟氯乙烯共聚物(ECTFE)微孔膜, 考察了ECTFE与不同溶剂的相互作用参数对ECTFE/溶剂体系的液液相区的影响, 通过相容性分析及对ECTFE微孔膜断面结构的观察, 筛选出能与ECTFE发生明显液液相分离的溶剂--邻苯二甲酸二乙酯(DEP). 热力学相图证明, ECTFE/DEP体系具有较宽的液液相分离区, 偏晶点所对应的ECTFE质量分数高达55%. 考察了冷却条件对{ECTFE/DEP体系膜断面结构的影响, 结果表明, 膜断面孔径随着淬冷温度的降低而减小, 在淬冷温度为458 K时膜断面孔径随粗化时间的增加而增大.

Preparation of Ethylene Chlorotrifluoroethylene Co-polymer Membranes via Thermally Induced Phase Separation

Microporous ethylene chlorotrifluoroethylene co-polymer(ECTFE) membrane was prepared via thermally induced phase separation(TIPS) method. By an analysis of interaction parameter, compatibility of ECTFE/diluent systems and the membrane cross-section morphologies, the liquid-liquid phase separation was found during the TIPS process when diethyl phthalate(DEP) was chosen as a diluent. The thermodynamic phase diagram confirms that a large liquid-liquid phase separation region for the ECTFE/DEP system was observed. The monotectic point of this system appeared at a high polymer concentration which was approximately up to 55%. Moreover, the effects of the cooling temperature and coarsening time on membrane structure, porosity, and tensile strength were also investigated. The results showed that a faster cooling rate and shorter coarsening time at 458 K led to membranes with smaller pore size.