α-Allyl Glucoside Modified Polymeric Membranes

To change the surface property from hydrophobic to hydrophilic efficiently and to improve the anti-fouling property, the modification of polyacrylontrile (PAN) and polypropylene (PP) membrane materials by using a-allyl glucoside (AG) as functional agent was introduced in this paper. For the modification of PAN, AG was incorporated into PAN by water-phase precipitation copolymerization and the obtained copolymer (PANCAG) was fabricated into membrane by immerse precipitation phase inversion method. For the modification of PP microporous membrane, AG was grafted onto the surface of PP membrane by Na-plasma induced graft polymerization method. The results demonstrated that the modified membranes combined the properties of high hydrophilicity, anti-fouling, and excellent biocompatibility.First, the copolymer was synthesized in dimethylsul- phoxide (DMSO) by the radical copolymerization of AG with AN using 2,2'-azobisisobutyronitrile(AIBN) as initiator. The copolymers were characterized by FT-IR and H'-NMR spectroscopy. It was found that the copolymer yields increased with increasing the initiator concentration as well as reaction time, and decreased with increasing the monomer ratio of AG/AN. Raising the proportion of AG in the monomer mixture principally increased the AG content in the copolymers. The Mv of the obtained copolymers decreased with increasing the AG monomer content and initiator concentration.In order to improve the Mv and AG content in the copolymer, AG was then incorporated into polyacrylonitrile by water-phase precipitation copolymerization with KiSiOg-NaiSOs as initiator system. The effects of initiator concentration, reaction time and temperature, and total monomer concentration on the copolymerization were studied and some results were compared with those of solution copolymerization using AIBN as initiator. FT-IR, 1H- and 13C- NMR spectroscopes, element analysis and DSC measurement were used to characterize the copolymers. It was found that both the yield and molecular weight for the WPPCP were higher than those for solution polymerization. The AG content in the resulted copolymersand the AG conversion for WPPCP were also higher than those of solution polymerization. The surface properties of the carbohydrate-containing copolymers were studied by pure water contact angle, protein adsorption and cell adhesion measurements. It was found that the contact angle of the copolymer films decreased from 68?to 30?with the increase of AG content in the copolymer. The adsorption amount of bovine serum albumin (BSA) and the adhesive number of macrophage on the film surface also decreased significantly with increasing the oc-allyl glucoside content from 0 to 42wt.% in the copolymer. These results revealed that both the hydrophilicity and biocompatibility of polyacrylonitrile-based membranes could be improved by copolymerization acrylonitrile with vinyl carbohydrates.The phase separation behavior of the copolymer dope was studied according to the linerized cloud point (LCP) correlation. It was found that the phase separation behavior of the systems, copolymer-solvent (DMSO)-nonsolvent (HaQ), agreed with the LCP correction. The binodal of the systems calculated according to the LCP correlation was shifted away the copolymer/DMSO axis with the increasing of the AG content in copolymer. The membranes prepared by immerse precipitation phase inversion method was characterized by water flux, BSA absorption, and SEM. The water flux increased with the increasing of AG content in copolymer, while the amount of BSA absorbed decreased with the increasing of AG content in copolymer which indicated that the modified membranes had high hydrophilicity and good biocompatibility.Finally, AG was grafted onto the surface of PP membrane by Na-plasma induced graft polymerization method. The chemical and morphological changes of the membrane surface of the grafted membranes were confirmed by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), pure...