Copolymers of 2‐hydroxyethyl methacrylate and alkyl methacrylates. I. Synthesis and characterization

Copolymerization of 2‐hydroxyethyl methacrylate (HEMA) with ethyl methacrylate (EMA) and n‐butyl methacrylate (BMA) was carried out in bulk at 70°C ± 1°C using 0.2% benzoyl peroxide as initiator in nitrogen atmosphere. Number average molecular weight (Mn) of the copolymers was determined by dynamic osmometry. Intrinsic viscosity [η] of HEMA‐BMA copolymers was evaluated at 35°C in dimethyl formamide. These copolymers were also characterized by infrared spectroscopy and density measurements. Cohesive energy densities (CED) of these polymers were determined by observing their swelling behavior in different solvents. It was found that a decrease in alkyl methacrylate content resulted in an increase in the CED values of the copolymers.