Preparation of PVA-g-NIPAAm Hydrogel by γ Radiation and Its Controlled Release Research
LIU Ning\ ZHAI Maolin\ LI Jun\ YI Min (Department of Technical physics, Peking University,Beijing,100871)
Thermosensitive PVA\|g\|NIPAAm copolymers was prepared by grafting copolymerization of N\|isopropylacrylamide (NIPAAm) onto poly(vinyl alcohol) (PVA) in homogeneous system by 60 Co\|γ irradiation at room temperature. The effects of radiation grafting conditions, such as absorption dose, dose rate, acid concentration on grafting yield were investigated. It was found that dose rate and acid concentration had obvious influence on the grafting yield. Then the hydrogels of PVA and PVA\|g\|NIPAAm copolymer were made through freezing\|thawing processes and the later hydrogels obtained in this method were found to exhibit obvious thermal sensitivity. In addition, the slow release of Methylene Blue (MB) from this kind of hydrogels was studied.