Physical properties of hydrogels of poly(2‐hydroxyethyl methacrylate) and copolymers with mono‐methyl itaconate synthesized by bulk and solution polymerization

The physical properties found during the swelling process of poly(2‐hydroxyethyl methacrylate) (PHEMA) and of copolymers of HEMA with mono‐n‐methyl itaconate, synthesized by solution and bulk polymerization, are reported. The swelling kinetics were followed at four different temperatures (295, 300, 305 and 310 K). Experimental data follow second‐order swelling kinetics, from where the kinetic rate constant k_∞ and the swelling capacity at equilibrium W_∞ were calculated as a function of temperature. The kinetic rate constant obeys Arrhenius behaviour. The following network parameters were determined for the hydrogels: Young's moduli E, effective crosslinking density v_e, molar mass per crosslink M_C, volume fraction ϕ₂ and polymer‐liquid interaction parameter χ. © 2000 Society of Chemical Industry