A Study of Graft Copolymers: I. Preparation and Viscosity Behavior

Abstract

Graft polymers were prepared by the redox polymerization of styrene in the presence of oxidized polystyrene or copolymers of styrene and 4-vinylcyclohexene-1; the maximum number of hydroperoxide groups per thousand monomeric units in the oxidized polymers was 18. Evidence that grafting had indeed occurred was obtained from measurements of monomer disappearance, of the decrease in hydroperoxide content of the backbone polymer during reaction, and of the infrared absorption by the polymer before and after the grafting procedure.Although the experimental results clearly support the conclusion that branching occurred, values of Huggins' k′ for both unfractionated and fractionated graft polymers were no higher than for linear polystyrene (0.39 < k′ < 0.41 in butanone). It was concluded that, though k′ is sensitive to bushy branching, Huggins' k′ is not measurably affected by the presence in a polymer of a few linear branches per molecule.