Hydrophilic Polymer Prepared By Dispersion Polymerization In An Aqueous

Dispersion polymerization is a unique polymerization process. During dispersion polymerization the polymer precipitates from the originally homogeneous reaction mixture containing monomer, initiator, solvent, and stabilizer. Polyacrylamide and poly(N-isopropylacrylamide)-poly(ethylene oxide) core-shell microgel were prepared by dispersion polymerization in an aqueous solution. And membrane of core-shell microgel dispersed in PVC or PS. The major work are as followed:1 Dispersion polymerization in an aqueous solution of ammonium sulfate using polyvinylpyrrolidone K-17 as stabilizer and potassium persulfate as the initiator was investigated. The polymerization temperature was between 25 and 35℃and stirring speed was preferable below 50 rpm.2 The core-shell microgels based on poly (N-isopropylacrylamide) (PNIPAM) and polyethylene oxide (PEG) were prepared by aqueous dispersion polymerization and were characterized by dynamic light scattering. The results showed PNIPAM-PEG microgels are temperature sensitive and volume phase transition temperature increase as PEG dosage increase. The type and dosage of cross-linker and dosage of PEG have apparent effect on diameter of microgel. Diameter of microgels crosslinked by PEG are bigger than those by N, N-methylenebisacrylamide. With increasing the PEG dosage, the diameter of microgels increase to a maximum and then decrease; Meanwhile the absolute value of electrophoretic mobility also increase to a maximum and then decrease.3 Membrane of PNIPAM-PEG core-shell microgels dispersed in PVC or PS was prepared, and characterized by contact angle and SEM. The results show that hydrophilicity and protein resistence of membrane of core-shell microgels dispersed in PVC or PS are better than those of PVC or PS.