滞空时间和凝固浴浓度对溶液相转化法制备BTDA-TDI/MDI膜结构及性能的影响

Effects of Evaporation Time and Coagulation Bath Concentration on the Morphology and Performance of BTDA-TDI/MDI Membrane by Solution Phase Inversion

采用3,3′,4,4′-二苯酮四酸二酐(简称酮酐)(BTDA)、甲苯二异氰酸酯(TDI)、4,4′-二苯基甲烷二异氰酸酯(MDI)为原料,在较低的温度下,通过"一步法"合成BTDA-TDI/MDI三元共聚聚酰亚胺,利用溶液相转化法成功制备聚酰亚胺(PI)微孔膜,探究了滞空时间和凝固浴浓度对膜结构和性能的影响.结果表明:随着滞空时间的延长,膜皮层厚度增大,皮层致密程度呈现先增大后减小的趋势,水通量呈现逐渐减小趋势,到达最小通量后开始回升,牛血清蛋白(BSA)截留率则呈现逐步增大趋势,到达峰值后开始下降;随着凝固浴浓度的增加,膜皮层厚度增大,膜厚减小,皮层致密程度变化不明显,水通量呈现逐步下降趋势,BSA截留率逐渐上升.

The BTDA-TDI/MDI ternary co-polyimides were synthesized via a one-step polycondensation procedure using benzophenone- 3,3′,4,4′-tetracarboxylic acid dianhydride（BTDA）,toluene diisocyanate（TDI）and 4,4′-methylenebis（phenylisocyanate）（MDI）at moderate temperature.Polyimide（PI）membranes were successfully prepared by solution phase inversion method.The effects of evaporation time and coagulation bath concentration on the morphology and performance of the resulting membranes were investigated.Experimental results indicate that the thickness of the skin layer increases while the dense of skin layer increases at first and then decreases,and water flux reaches the minimum whilst the retention to bovine serum albumin（BSA）reaches the maximum with the extension of evaporation time.And it is also found that the thickness of the skin layer increases while the thickness and water flux of the membrane decrease gradually,and the dense of skin layer changes little while the retention to BSA increases when the coagulation bath concentration increases.