聚偏氟乙烯有机膜的共混改性及性能研究

STUDY ON BLENDING MODIFICATION AND PERFORMANCE OF PVDF ORGANIC MEMBRANE

将聚偏氟乙烯和高分子聚合物共混,通过溶胶-凝胶相转化法研制综合性能良好的微孔膜,考察了铸膜液浓度、PVDF与共混添加剂的配比、凝胶浴温度、溶剂挥发时间和酸、碱、氧化处理对共混膜性能的影响。结果表明,随着铸膜液中聚合物总含量、膜液的黏度增加,纯水通量总体呈下降趋势,孔隙率先增加后减小,最后趋近平衡;随着共混添加剂在铸膜液中相对含量的增加,纯水通量先增加后减小,孔隙率可得到有效提高,平均孔径变化不大;凝胶浴温度对纯水通量没有较大影响;延长溶剂的挥发时间,使平均孔径减小;找到合适的共混添加剂并选择适当的膜液组成,能够使共混改性膜的纯水通量、孔隙率、抗酸、碱、氧化性能较改性前得到有效提高。其中纯水通量较改性前提高10%左右,孔隙率提高15%左右,说明共混化是一种改善PVDF膜性能的有效方法,具有极好的实用开发价值。

PVDF was blended with polymer,and by means of sol-gel transformation（L-S method）,the microporous membrane with favorable combination property was prepared.The effects of polymer concentration,ratio of PVDF with blending additives,solvents,temperature of coagulation bath,solvent volatilization time and acid,alkali,oxidation treatment on the membrane performance were studied.The results under the experimental conditions showed that： membrane liquid viscosity increased as membrane liquid concentration increased,and pure water flux was downtrend in general as well as the porosity of the membrane was increased first,then decreased,at last balanced;pure water flux was increased,then decreased as the concentration of blending additive was increased,and porosity could be effectively improved as well as average aperture was changed little;pure water flux had no greater influence as the temperature of coagulation bath changed;average aperture was reduced by extending the solvent volatilization time;pure water flux,porosity,acid resistance,alkali resistance,oxidation resistance could be improved than before by finding the right blending additives and selecting proper membrane liquid composition.Pure water flux could be increased by about 10% and porosity could be increased by about 15% than the membrane unmodified,so it was proofed that blending was a good method to improve the performance of PVDF membrane,and it had excellent practical development value.