Copolymers of N-acryloyl-N'-methylpiperazine (AcrNMP) and 2-hydroxyethyl methacrylate (HEMA) were synthesized by free radical solution polymerization in dioxane at 70 +/- A 1 A degrees C, using 2,2'-azobisisobutyronitrile (AIBN) as initiator. The copolymer compositions were analyzed by the methods of FTIR spectroscopy and elemental analysis. Both the method of analysis yielded results that agreed reasonably well. The monomer reactivity ratios of the copolymerization were determined by the linearization methods of Finemann-Ross (FR) and Kelen-Tudos (KT). The reactivity parameter results derived using FTIR analysis showed that the copolymerization yielded mainly alternating structure with reactivity ratios, r (1)(AcrNMP) = 0.263 +/- A 0.011 and r (2)(HEMA) = 0.615 +/- A 0.097 by F-R method and r (1) = 0.227 +/- A 0.074 and r (2) = 0.53 +/- A 0.15 by KT method. Microstructure data calculated by the method of Igarashi also supports the alternating structure (tendency) of the copolymer. Crosslinked polymer gels of this system exhibited remarkably high swelling of more than 500% in water at ambient temperature.