Chemical inhomogeneity of terpolymers of styrene with acrylonitrile and methyl methacrylate

Abstract The method of light scatter has been used to study terpolymers of styrene with acrylonitrile and methyl methacrylate of the following composition (in parts by weight) 0·65 : 0·13 : 0·22 (copolymer 1), 0·60 : 0·14 : 0·26 (copolymer 2), 0·52: 0·15 : 0·33 (copolymer 3) and 0·30 : 0·07 : 0·63 (copolymer 4), and the fractions of copolymer 4 obtained from the solvent-precipitant system methylethylketonemethanol to make a quantitative evaluation of the general parameters of chemical inhomogeneity P A , P B , Q A , Q B and R . The measurements were made in methylethylketone, THF, 1,4-dioxane, toluene, chlorobenzene, bromoform, bromobenzene and aniline. It was found that the overall chemical inhomogeneity Q / Q max of the samples studied even for low (≈10%) depths of conversion is high for compositions near to (copolymers 1 and 2) and distant from (copolymers 3 and 4) the azeotropic region, being 28 and 59–62% respectively. The chemical inhomogeneity of the fractions is close to that for the initial sample, which indicates the suitability of the system methylethylketone-methanol for separating copolymer 4 by molecular weight.