Molecular weight and long‐chain branching distributions of some polybutadienes and styrene–butadiene rubbers. Determination by GPC and dilute solution viscometry

Abstract A method described for the determination of molecular weight and long‐chain branching distributions of polymers requires no prior knowledge of the functional relation between branching frequency and molecular weight. It is based on preparative fractionation and viscometric and gel‐permeation chromatographic measurements on both fractions and whole polymer. The technique is applied to several polybutadienes and butadiene‐styrene copolymers differing widely in method of synthesis and pattern of long‐chain branching.