PVDF/PU相容性及其复合管状膜的制备

Preparation of composite tubular membrane of polyvinylidene difluorid and polyurethane

采用溶解度参数和混合焓计算预测聚偏氟乙烯(PVDF)/聚氨酯(PU)的相容性,用黏度法测试了PVDF/ PU共混溶液的混容性,用浊度法测试了PVDF/PU共混制膜体系的热力学性质,并制备了PVDF/PU复合管状膜。结果显示,PVDF/PU属于部分相容体系,当w(PU)为10%～90%时,制膜体系的凝胶值由5.30增至9.93,体系更加倾向于发生快速的液液分相,导致复合膜孔隙率增加,当w(PU)为0～40%时,水通量从2456.21/(m^2·h)增至5830.91/(m^2·h)

The authors predicted the compatibility between polyvinylidene difluorid （PVDF） and polyurethane （PU） in terms of their solubility parameters and calculation of mixing enthalpy, tested the miscibility of the mixed solution of PVDF and PU by viscometry and measured the thermodynamic properties of the membrane-forming system of PVDF/PU blend with nephelometry. A kind of composite tubular membrane was fabricated from the PVDF/PU blend. The analytical results show that PVDF/PU blend can be classified into the category of partially compatible systems. When PU content rises from 10% to 90%, the gelation value of the membrane-forming system increases from 5.30 to 9.93, respectively; at the point, the instan-taneous liquid-liquid phase separation much more preferably to occur in the system, and thereby leading to an increase in porosity of the membrane. When the PU content is in the range of 0-40%, the water flux of the composite tubular membrane increases from 2 456.2 to 5 830.9 L/（m^2·h）.