SYNTHESIS AND FUNCTIONALITIES OF POLY(N-VINYLALKYLAMIDE) .6. A NOVEL THERMOSENSITIVE HYDROGEL CROSS-LINKED POLY(N-VINYLISOBUTYRAMIDE)

A novel thermosensitive poly(N-vinylisobutyramide)(polyNVIBA) hydrogel was prepared by the copolymerization of N-vinylisobutyramide (NVIBA) with butylene-bis-NVA(B-BNVA) as a crosslinker in a high yield. The sw elling transition behavior was examined in comparison with poly (N-iso propylacrylamide) (polyNI-PAAm) hydrogel. The resulting polyNVIBA hydr ogel clearly showed a swelling transion in water at ca. 41 degrees C. To control the transition temperature (T-t) of the gel, crosslinked co polymers of NVIBA and N-vinylacetamide (NVA) were prepared and compare d with copolymers of N-isopropylacrylamide (NIPAAm) and NVA. The incor poration of NVA led to a higher swelling transition temperature. T-t o f poly(NVIBA-co-NVA) gels was almost the same as those in water-solubl e poly(NVIBA-co-NVA). The responses for a swelling transition of polyN VIBA and poly(NVIBA-co-NVA) gels were sharp in comparison to polyNIPAA m gels. PolyNVIBA and poly(NVIBA-co-NVA) gels desorbed 98% of water ab ove T-t. The characteristic and the mechanism of the phase transition on the hydrogels were discussed. (C) 1997 John Wiley & Sons, Inc.