The influence of molecular interaction on polymerization, 10. On the copolymerization of methacrylic acid with styrene

Abstract

Abstract Free radical copolymerization of methacrylic acid (MA) with styrene (St) at 60°C, initiated by 2,2′‐azoisobutyronitrile (AIBN) is carried out in hydrogen‐bond forming solvents and in solvents not capable of forming hydrogen bonds but exhibiting different dielectric constants. The influence of the solvent on copolymerization reactivity ratios, rate of polymerization, composition, molecular weight and polydispersity of the copolymers obtained is shown. The reactivity ratios of methacrylic acid r MA and of styrene r St are determined by two different methods with good agreement. The values obtained by the Kelen‐Tüdös method are as follows: in carbon tetrachloride: r MA = 0,54 ± 0,01; r St = 0,06 ± 0,03; in chloroform: r MA = 0,51 ± 0,01; r St = 0,08 ± 0,03; in acetone: r MA = 0,43 ± 0,00; r St = 0,65 ± 0,02; in 1,4‐dioxane: r MA = 0,41 ± 0,02; r St = 0,59 ± 0,05; in acetonitrile: r MA = 0,06 ± 0,02; r St = 0,29 ± 0,00. Changes of reactivity ratios depending on the medium are explained on the basis of the results from IR and 1 H NMR spectroscopy and gel permeation chromatography (GPC).