Improvement of persistent hydrophilicity and pore uniformity of polyvinyl chloride ultrafiltration membranes by in-situ crosslinking reaction assisted phase separation

A novel in-situ crosslinking reaction assisted phase separation strategy was proposed for persistent hydrophilization and pore size regulation of polyvinyl chloride (PVC) membranes. In-situ cross-linking between PVC molecular chains was achieved through grafting of 3-aminopropyltrimethoxysilane (APTMS) during the dissolution process and cross-linking reactions between siloxanes in APTMS molecules initiated by the coagulation bath (water). The effect of in-situ crosslinking reaction on the structure, separation and anti-fouling performance of the PVC membranes was studied. Through in-situ crosslinking reaction induced phase separation, the migration and curing of polymer molecular chains in the phase separation process were regulated, which endowed the modified membrane with improved hydrophilicity, higher porosity and narrow pore size distribution. The pure water flux of the obtained membrane increased 3.5 times as much as that of the pure PVC membrane. In addition, the flux recovery rate (FRR) of the obtained membrane was increased by 15.9% and the strength was also increased slightly at the same time. The stability of the membranes was also improved, without chemical agents leaching during filtration, avoiding secondary pollution to our environment.