Study of the dual role mechanism triggered by in-situ cross-linking in hollow fiber membrane matrix

Abstract

In this paper, a novel polyvinylidene fluoride (PVDF) hollow fiber membrane with uniform pore size and hydrophilic cross-linked network in membrane matrix was developed by non‐solvent induced phase separation method. The dual role mechanism of in-situ cross-linking in regulating molecular chain arrangement during phase separation and preventing deterioration of membrane mechanical properties were analyzed. The results demonstrated that the cross-linked network formed by in-situ crosslinking entangled with PVDF molecular chains which improved the regularity of PVDF molecular chains, increasing the uniformity of the pore size distribution, the percentage of the most probable pore size of the modified membrane increased to 93.25%. The cross-linked network was immobilized in the membrane which formed semi-interpenetrating structure, maintaining the mechanical properties of the membrane. The permeation flux of the modified membrane increased by 24.1 times to 477.7 L·m-2·h-1 compared to the original PVDF membrane. The rejection of BSA was maintained at 98.5%, with the tensile strength increased to 2.52 MPa. The modified membrane exhibited persistent hydrophilicity in 21 days washing experiment with improved antifouling performance.