Comparison of the molecular weight and size measurement of polyisobutylenes by size exclusion chromatography/multi‐angle laser light scattering and viscometry

Abstract

This note reviews hyphenated size exclusion chromatography (SEC) techniques and compares polyisobutylene SEC analyses by multi-angle laser light scattering and viscometry. The weight-average molecular weight and number-average molecular weight were found to be independent of the molecular weight measurement technique used. The reproducibility was found to be better when a known refractive-index increment was used. Significantly, large differences were found in z-average molecular weight data measured by the different techniques. The low shear (Mooney) viscosity correlated well with the weight-average molecular weight and z-average molecular weight only in the case of good SEC separation.