Mean‐Square Radius of Gyration and Degree of Branching of Highly Branched Copolymers Resulting from the Copolymerization of AB2 With AB Monomers

Abstract Summary: The evolution of the various structural units incorporated into hyperbranched polymers formed from the copolymerization of AB2 and AB monomers has been derived by the kinetic scheme. The degree of branching was calculated with a new definition given in this work. The degree of branching monotonously increased with increasing A group conversion (x) and the maximum value could reach 2r/(1 + r)2, where r is the initial fraction of AB2 monomers in the total. Like the average degree of polymerization, the mean‐square radius of gyration of the hyperbranched polymers increased moderately with A group conversion in the range x < 0.9 and displayed an abrupt rise when the copolymerization neared completion. The characteristic ratio of the mean‐square radius of gyration remained constant for the linear polymers. However, the hyperbranched polymers did not possess this character. In comparison with the linear polymerization, the weight average and z‐average degree of polymerization increased due to the addition of the branched monomer units AB2 and the mean‐square radius of gyration decreased quickly for the products of copolymerization. magnified image