Photografting modification of PET nucleopore membranes

摘要

PET nucleopore membranes were modified by photografting polymerization. The grafted membrane has a well-defined structure. Grafting polymerization is confined on the membrane surface; no graft occurs inside membrane pores. The grafted PAA was characterized with ESCA, and the morphology of grafted membranes was observed by SEM. The high monomer concentration, temperature and UV intensity is beneficial to the increase of grafting degree (D-g). BP as initiator has an optimized concentration due to the self-screening. Membrane surface was changed into hydrophilic via. 10 sec. treatment. The competition of water affinity of membrane surface and swelling-cover effect of grafted layer result in the filtration rate of grafted membranes varied with the D-g. At low D-g, flux is larger than that of blank membrane; at high D-g, the swelled PAA chains on the membrane surface cover the membrane pores and thus the flux decreases dramatically even close to zero, whereas SEM shows that the membrane pores are still open in dry state. [References: 12]