Determination of molecular weights of carboxy-terminated styrene-methacrylonitrile copolymers by titrimetry

The study aimed to determine the molecular weights of carboxy-terminated styrene-methacrylonitrile homo-and random copolymers, which were previously prepared by the free radical chain transfer process, by titrimetry. The molecular weights obtained from this study were compared with the molecular weights obtained previously from Gel Permeation Chromatography (GPC) to give information on the degree of functionalization of the polymers. The polymer samples were titrated with 0.0125 M standard sodium hydroxide solution until the phenolphthalein endpoint. The molecular weights obtained in this study were too small compared to the molecular weights obtained from GPC, giving low values for the degree of functionalization. This means that during the chain transfer process, the chain transfer agent, HETMAA, wasn\u27t efficient enough in incorporating the carboxyl end group to the polymer chain of styerene and methacrylonitrile