SWELLING BEHAVIORS OF N-ALKYLACRYLAMIDE GELS IN WATER - EFFECTS OF COPOLYMERIZATION AND CROSS-LINKING DENSITY

N-isopropylacrylamide (NIPA)/N-n-propylacrylamide (NNPA) copolymer gels of various molar ratios were prepared by radical polymerization and the relationship between the swelling behaviour of the gels and the copolymerization ratio was studied experimentally. The effect of a crosslinking point on the swelling behaviour of the NIPA gels was investigated by preparing the gels with various crosslinking densities. The results of our experiments revealed that the transition temperatures of the NIPA/NNPA copolymer gels were changed in proportion to the monomer ratio used in copolymerization and that the crosslinking density strongly affected the swelling ratios but not the transition temperatures of the gels.