PVDF/PMMA/CA共混膜的制备及性能研究

主要讨论了PVDF(聚偏氟乙烯)／PMMA(聚甲基丙烯酸甲酯)／CA(醋酸纤维素)三元共混膜的制备及性能，并研究了影响膜性能的主要因素．正交实验结果表明：在PVDF／PMMA／CA体系中，PVDF同亲水性物质PMMA和CA的共混比是影响共混膜的水通量的首要因素；而PMMA与CA的共混比则对共混膜强度影响最大，当PMMA与CA的质量共混比为1：1时，膜强度最大；PMMA对膜的亲水性有较大的贡献，共混膜中只要有PMMA加入，其润湿角就变得同纯PMMA膜的润湿角相接近，通过采用红外衰减全反射法和干膜撕裂法，分别从微观和宏观上证明了PVDF／PMMA/CA气制膜体系在自来水中将会发生分层凝胶现象；综合考虑膜的各种性能，针对PVDF／PMMA／CA体系，较佳的制膜条件定为A883C2D12，也就是PVDF/CA/PMMA的质量共混比为12：2：1，以质量溶剂比为8：2的二甲基甲酰胺(DMF)／冰乙酸混合溶剂溶解，制得的膜的性能较好．

Study of the preparation of PVDF/PMMA/CA blend membrane and its properties

The preparation of PVDF/PMMA/CA blended membrane and its properties were investigated and discussed, and the best conditions of preparing membrane were obtained. That is to say, when the mass ratio of m(PVDF)/m(CA)/m(PMMA) was 1221 and that of solvent m(DMF)/m(CH_3COOH) was 82, the membranes' properties were better. By the square-crossing test, the following conclusions were drawn. Firstly, the mass ration of PVDF to PMMA and CA influenced significantly the water flux of blend membranes, while the mass ration of PMMA to CA was the most important factor affecting the membrane strength. When the mass ratio of PMMA to CA was 11, the membrane strength was the best. What is more, the ingredient PMMA contributed to the hydrophilic of blend membrane, so the hydrophilic polymer with less weight may be the better choice if the hydrophilic property is expected to enhance. Finally, it was identified that layered gelation will happen for the system of PVDF/PMMA/CA.