Zirconocene-catalyzed copolymerization of methyl methacrylate with other methacrylate monomers

Statistical copolymers of methyl methacrylate (MMA) with n-butyl-, s-butyl, t-butyl-, n-hexyl-, decyl-, stearyl-, allyl-, trimethylsilyl- and trimethylsilyloxyethyl methacrylate were prepared by zirconocene-catalyzed copolymerization. The reactivity ratios of MMA copolymers with butyl-, hexyl-, and stearyl methacrylate were estimated using the Finemann-Ross, the inverted Finemann-Ross, and the Kelen-Tüdos graphical methods. Structural parameters of the copolymers were obtained from the calculated dyad sequences, derived by using the reactivity ratios. The effect of the nature of the methacrylate ester group and the catalytic system used on the copolymer structure is discussed. The glass-transition temperature (T_g) values of MMA copolymers with butyl- and hexyl methacrylate were measured and examined in the frame of several theoretical equations, allowing the prediction of these T_g values. The best fit was obtained using Barton and Johnston equations, taking the monomer sequence distribution of the copolymers into account.