The effects of allylmethacrylate on the copolymer of allylmethac-rylate and methylmethacrylate have been studied by varying the allylmethacrylate content in the feed from 5% to 30% by volume. It has been found that above 15% allylmethacrylate content in the feed, the molecular weight between crosslinks increases, reducing the crosslink density and thereby causing a reduction in the mechanical properties. Up to 10% allylmethacrylate, the strength remains high and the modulus also increases; and up to 15% the modulus increases but the strength value drops down. There is a sharp drop in both strength and modulus after 15%. Thus the addition of 10% allylmethacrylate has been found to give the optimum mechanical properties.