Abstract:

To improve the hydrophobic performance of polypropylene (PP) microporous membranes for gas-liquid separation, the polysiloxane-silica and polypropylene resin were blended and made into hydrophobic polypropylene hollow fiber membranes by the melt-stretching method. DSC, TGA, SEM, AFM, porosity, water contact angle and gas/pure water fluxes were carried out to investigate the effect of polysiloxane-silica contents on the structure and performance of the hollow fiber membrane. The results showed that as the polysiloxane-silica content increased, the water contact angle of the membrane gradually increased, and the average pore size, pure water flux and gas flux indicated a trend of increasing and then decreasing. When the polysiloxane-silica content increased from 0 to 2%, the water contact angle of the membrane increased from 108.6° to 127.6°, indicating that the hydrophobicity of the PP microporous membrane was significantly improved. The membrane porosity was 59.4%, and the gas flux was 61.76L/(m²∙s), which was 2.16 times that of the pure PP membrane. Additionally, the polysiloxane-silica played the role of heterogeneous nucleation, improved the annealing effect, and made the structure of the main lamellae stable. The pore structure still consisted of separated lamellae crystals.

Key words: polysiloxane, silica, polypropylene microporous membrane, hydrophobicity

摘要：

为了提高气液分离用聚丙烯（PP）微孔膜的疏水性能，本研究将聚硅氧烷-二氧化硅纳米粒子和聚丙烯树脂熔融共混，采用熔融-拉伸法制备疏水聚丙烯中空纤维膜，进行了差示扫描量热仪、综合热分析仪、扫描电子显微镜、原子力显微镜、孔隙率、水接触角、气体/纯水通量等测试与表征，研究了不同含量的聚硅氧烷-二氧化硅对中空纤维膜结构和性能的影响。结果表明，随着聚硅氧烷-二氧化硅质量分数的增加，膜的水接触角逐渐增大，平均孔径、纯水通量和气体通量均呈现先增大后减小的趋势。当聚硅氧烷-二氧化硅质量分数为2%时，膜的水接触角从108.6°增加到127.6°，表明PP微孔膜的疏水性能得到明显改善。膜孔隙率为59.4%，气体通量为61.76L/(m²∙s)，是纯PP膜的2.16倍。同时聚硅氧烷-二氧化硅可以起到异相成核的作用，改善聚丙烯PP微孔膜的退火效果，使主片层结构变得稳定，孔结构依然由分离的片晶组成。

关键词: 聚硅氧烷, 二氧化硅, 聚丙烯微孔膜, 疏水性