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

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.