Effect of crosslinker on properties of copolymeric N‐vinyl‐2‐pyrrolidone/methyl methacrylate hydrogels and organogels

The γ‐ray initiated copolymerisation of N‐vinyl‐2‐pyrrolidone with methyl methacrylate in the presence of crosslinker has been effected to high conversion. At two fixed compositions of the principal monomers, the inclusion of different concentrations of the tetrafunctional crosslinkers ethylene dimethacrylate and a low molar mass poly(ethylene glycol) dimethacrylate produced crosslinked xerogels, which were subsequently swollen in water and 1,4‐dioxane to yield hydrogels and organogels, respectively. These gels were characterised by determinations of sol fraction, equilibrium solvent content and uniaxial compression stress/strain measurements. Differences among the swelling and mechanical properties according to the nature and concentration of crosslinking agent and according to the nature of the swelling medium are noted and discussed.