Branching Analysis of Comb-Shaped Polystyrene with Long Chain Branches

Abstract

Model comb-shaped polystyrene (PS) samples are synthesized by anionic polymerization and the as-prepared PS heterogeneous combs are further fractionated by temperature gradient interaction chromatography (TGIC) to obtain well-defined random combs with 1?4 branches at random positions on a backbone. Size exclusion chromatography-triple detection and TGIC-triple detection analyses are carried out with the fractionated PS random combs in a good and a theta solvent, respectively. The experimentally observed geometric contraction factor (g), the ratio of the mean square radius of gyration and the hydrodynamic contraction factor (g��), and the ratio of the intrinsic viscosity are compared. It is observed that the two contraction factors follow the relationship of g�� = g�� reasonably well and the exponent �� of the PS combs is found as ��1 in a good solvent and ��0.66 in a theta solvent. Furthermore, it is found that the theoretical grw is not in good agreement with the experimental results. (Figure presented.). ? 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim