N-ethylacrylamide (NEA)

N-n-propylacrylamide(NNPA)

N-iso-propylacrylamide (NI-PA)

piperidylacrylamide(PRA)

N

N-diethylacry/lamide(NDEA)(and N

N-dimethylacrylamide (NDMA) monomers and the hydrogels of their copolymers with N

N'-methylene-bis-acrylami-de (BiS) have been synthesized. It was found that PNEEA

PNNPA

PNIPA

PPRA and PNDEA hydrogels undergo a discontinuous phase transition during

temperature variation. The effects of monomeric structures

composition of the starting monomeric mixture and the polymerization temperature on the formation

structural heterogeniety and swelling characteris-tics of the hydrogels have been systematically studied. The relative reactivities of Bis and NIPA and the cause of the structural heterogeneity were proposed.