Radical copolymerization of 2-vinyl pyridine and oligo(ethylene glycol) methyl ether methacrylates: Monomer reactivity ratios and thermal properties

Statistical copolymers of 2-vinylpyridine (VP) with oligo(ethylene glycol) methyl ether methacrylates of two different molecular weights (300 g/mol (OEGMA300) and 1100 g/mol (OEGMA1100)), were prepared by free radical polymerization. The reactivity ratios of these two sets of monomers were estimated using the Finemann-Ross, the inverted Finemann-Ross and the Kelen-Tüdos graphical methods. Structural parameters of the copolymers were obtained by calculating the dyad monomer sequence fractions and the mean sequence length. The effect of the length of the oligo(ethylene glycol) group on the copolymer structure is discussed. The glass-transition temperature (Tg) values of the VP copolymers with OEGMA300 were measured and examined in the frame of several theoretical equations, allowing the prediction of these Tg values. The copolymers of VP with OEGMA1100 exhibited the characteristic melting endotherm, due to the crystallinity of the methacrylate sequences and glass transition temperatures attributed to the PVP sequences.