热氧化交联对PPS膜性能的影响

Effect of thermal oxidation crosslinking on performance of PPS membrane

为了解决聚苯硫醚(PPS)膜通量低、截留率低、力学性能差以及在极性溶剂中易溶胀等问题,提出在200~260℃不同温度空气气氛下进行不同阶段热氧化交联来提高PPS膜的应用性能。结果表明:在260℃处理后,成膜后热氧化的PPS膜纯水通量增加到129.74 L/(m^2·h),但是对牛血清蛋白(BSA)的截留仍维持在62%,这说明热氧化交联致使PPS膜表面出现熔融,微量溶剂的二次蒸发形成了更多的孔;而成膜前热氧化的PPS膜纯水通量和截留率都发生改变,分别为78.72 L/(m^2·h)和98.73%;同时,通过在高温空气中独立的聚合物链的热氧化交联形成具有网络结构的PPS聚合物,PPS膜的机械性能都有提高,成膜前热氧化的PPS膜的拉伸强度从1.71 MPa提高到4.48 MPa;交联后的PPS膜在极性溶剂中表现出优异的耐溶胀性能。由此得出热氧化交联能够快速提升PPS分离膜的应用性能。

In order to solve the problems of PPS membrane,such as low flux,low rejection rate,poor mechanical properties,and easy swelling in polar solvents,it is proposed to improve the application performance of the film by performing thermal oxidation crosslinking in different stages under air atmospheres at 200-260℃.The results show that after treatment at 260℃,the pure water flux of the thermally oxidized PPS membrane increased to 129.74 L/(m^2·h)after membrane formation,but the retention in BSA was still maintained at 62%,which indicates that thermal oxidation crosslinking caused the membrane surface melting occurred,and evaporation of trace solvents formed more pores;however,the pure water flux and rejection rate of the thermally oxidized PPS membrane before membrane formation changed to 78.72 L/(m^2·h)and 98.73%,respectively.At the same time,the PPS polymer with a network structure is formed by thermal oxidation crosslinking of independent polymer chains in high-temperature air,and the tensile strength of the membrane is greatly improved.The tensile strength of the thermally oxidized PPS membrane was improved from 1.71 MPa to 4.48 MPa.The membrane after crooslinked showed excellent swelling resistance in polar solvents.In summary,thermal oxidation crosslinking can quickly improve the application performance of PPS separation membranes.