TIPS法iPP中空纤维膜的拉伸性能研究

Morphology and permeability of iPP hollow fiber membrane via thermally induced phase separation after stretching

通过熔融共混等规聚丙烯(iPP)/邻苯二甲酸二丁酯(DBP)/邻苯二甲酸二辛酯(DOP)体系,采用热致相分离法(TIPS)制备iPP中空纤维膜,且在不同的拉伸温度及拉伸比下对中空纤维膜进行拉伸研究.对膜结构与透过性能进行了表征.采用环境扫描电子显微镜(SEM)对膜的内、外表面以及截面结构进行观测,发现拉伸后膜外表面的皮层以及膜结构得到有效改善.使用电子式万能试验机对中空纤维膜的拉伸强度进行了测试.随着拉伸温度和拉伸比的增加,膜的孔隙率、纯水通量以及拉伸强度均呈现先增大后减小的趋势.膜的孔隙率最大可提高35.3%,纯水通量提高了286.9%,拉伸强度可提高至6.86 MPa.nano-SiO2(纳米SiO2)添加的杂化膜经过拉伸后,孔隙率增大了46.8%,纯水通量提高了416.1%,拉伸强度提高了181.9%.研究表明:通过对iPP中空纤维膜进行拉伸处理,可以优化膜结构,并改善了膜表面皮层以及透过性能.

By melting and blending isotactic polypropylene （iPP）/di-n-butyl phthalate （DBP）/ dioctyl phthalate（DOP） system, iPP hollow fiber membrane was prepared via thermally induced phase separation （TIPS） method. Subsequently, the hollow fiber membranes were stretched at different stretching temperature and stretching ratio. The membrane structure and permeability were characterized. The cortex on the outer surface of the membrane and the membrane structure have been made better, which were observed with environmental scanning electron microscope. The tensile strength of hollow fiber membrane was tested by electronic universal testing machine. The porosity, the pure water flux and the tensile strength of the membrane increase firstly and then decrease, with increasing stretching temperature and stretching ratio. The porosity increases by 35. 3%, the pure water flux of the membrane raises by 286.9% and the tensile strength can increases to 6. 86 MPa. The performance of the hybrid membrane which was added with nano-SiO2 after the stretching is improved： the porosity raises by 46.8%, the pure water flux increases by 416. 1% and the tensile strength can raise by 181.9%. It is suggested that the cortex on the outer surface and the permeability of the membrane can be made better by stretch processing which can optimize the membrane structure.