Study on interface structure and performance of homogeneous-reinforced polyvinyl chloride hollow fiber membranes

Homogeneous-reinforced (HR) polyvinyl chloride (PVC) hollow fiber membranes consisting of coating and matrix layers were fabricated via coating process. The mixtures of polymer solutions were uniformly coated on the homogeneous PVC matrix membrane which was prepared by melt-spinning method. The influence of various pre-wetting solutions on interface structure and performance of HR membranes were investigated. The results showed that the HRPVC membranes had a dense and smooth outer surface with no obvious pores. A dense interface was formed in the HR membrane between the coating layer and the matrix membrane without pre-wetting process. Due to the filling of the pores of the outer edge of the matrix membrane by pre-wet solutions, the HRPVC hollow fiber membranes formed porous interface in the coating process. The pure water flux of the pre-wet HR membranes was higher than that of the un-pre-wet HR membrane, but lower than that of the matrix membrane. The optimum properties of HRPVC membranes were obtained as the ethanol weight fraction reached 60 wt% in the pre-wet solutions. In the optimum pre-wetting conditions, the tensile strength of HRPVC hollow fiber membranes was 9.5 MPa, while the elongation-at-break value was 97.4 %.