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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。
Polyvinylidene fluoride (PVDF) and macromolecule polymer were blended to prepare microporous microporous film with good comprehensive properties by sol-gel phase inversion method. The effects of casting solution concentration, ratio of PVDF and blending additive, temperature of gel bath, Effect of solvent evaporation time, acid, alkali and oxidation on the properties of blends. The results showed that with the increase of the total polymer content and the viscosity of the membrane liquid, the pure water flux decreased, the porosity first increased and then decreased, and finally approached the equilibrium. As the blending additive in the casting solution The flux of pure water increased first and then decreased, the porosity could be effectively increased, and the average pore diameter did not change much. The temperature of the gel bath had no significant effect on the pure water flux. The solvent evaporation time was extended to The average pore size decreases; finding suitable blending additives and selecting the proper membrane liquid composition can effectively improve the pure water flux, porosity, acid resistance, alkali resistance and oxidation performance of the modified membrane. Among them, the flux of pure water increased about 10% compared with that before modification, and the porosity increased about 15%, indicating that blending is an effective method to improve the properties of PVDF membrane and has excellent practical value.