Estimation of Molecular Weight Distribution of Elastomers and Polymer Melts through Dynamic Rheometry

Abstract

This work presents a rheometric molecular weight distribution technique (RMWD) to estimate molecular parameters of low and high poly dispersity samples of elastomers and polymer melts. Samples of polystyrene, polybutadiene, polyethylene and styrene-butadiene rubbers are considered in this study. Important conclusions are obtained concerning the elimination of experimental information with glassy modes that are not relevant for the RMWD technique. A discussion on the calibration of this technique is pre sented involving an interplay with size exclusion chromatography and capil lary rheometry. Estimation of molecular weights M_w and M_n, and polydisper sity Po through rheometry is a promising technique, which when comple mented with rheological theories of polymer melts, may give additional infor mation into the chemical architecture of polymer chains. Correlations between rheological and molecular parameters are also presented.