第2凝固浴对气-液膜接触器用PVDF膜润湿性能的影响

Effect of the Second Coagulation Bath Composition on Wettability of Polyvinylidene Fluoride for Gas-liquid Membrane Contactor

以聚偏氟乙烯(PVDF)为基膜材料,以乙醇为第1凝固浴,以不同N-甲基吡咯烷酮(NMP)含量的水溶液为第2凝固浴,采用双凝固浴法制备了高疏水和高透气的PVDF膜。结果表明,以水作为凝固浴时,PVDF膜的空气侧较为平整,当用双凝固浴时,PVDF膜空气侧开孔结构和无皮层结构逐渐明显,PVDF膜基底侧较为粗糙;随着NMP含量的增大,膜的接触角先增大后减小,当第2凝固浴中的NMP的质量分数为50%时,接触角、最小液体渗透压力、通气量最大,分别为141.9°、35 kPa、540 L/h。

Using polyvinylidene fluoride （PVDF） as basement membrane material, ethanol as the first coagulation bath, water solution with different N- methylpyrrolidone （NMP） content as the second coagulation bath, the high hydrophobic and high permeability PVDF membranes were fabricated by dual bath coagulation method. The results showed that the top surface of PVDF membrane with water as coagulation bath was smooth, the top surface of PVDF membrane with NMP water solution as coagulation bath was open structure and none skin, and the bottom surface of PVDF membrane with NMP water solution as coagulation bath was rough. When the mass fraction of NMP was 50% in the second coagulation bath, the contact angle, LEPw and maximum throughput was 141.9°, 35 kPa and 540 L/h respectively.