Evaluation of the spacer effect on adamantane-containing vinyl polymer Tg's

Two new adamantane-containing methacrylates having methylene and phenyl spacers between the adamantane and the methacrylate were synthesized:  1-adamantylmethyl methacrylate (AdMMA, 1) and 4-(1-adamantyl)phenyl methacrylate (AdPMA, 2). The homopolymer of 1 had a Tg of 201 °C while 2 showed a Tg of 253 °C. Copolymers of both monomers with styrene (St) showed significant Tg increases over PSt. The incremental increase obtained with AdPMA per adamantane unit is the highest of all vinyl monomers reported to date, to the best of our knowledge, with a value of 2.2 °C/mol %. Both sets of copolymers showed higher incorporation of adamantane monomers in the copolymer than the feed, with reactivity ratios calculated to be r1(St) = 0.22 and r2(AdPMA) = 1.52 and r1(St) = 0.94 and r2(AdMMA) = 1.54.