SAXS/DSC Analysis of the Lamellar Thickness Distribution on a SSA Thermally Fractionated Model Polyethylene

Abstract

Successive self-nucleation and annealing (SSA) is applied to thermally fractionate a model hydrogenated polybutadiene. SSA produces discrete and well-separated thermal fractions with distinct melting peaks. The samples are studied by SAXS as a function of temperature. The SAXS profile displays only one scattering peak associated with the interlamellar correlation and is unable to discriminate the multimodal distribution of lamellar thicknesses in the samples. The average lamellar thickness associated with each melting fraction can be estimated from SAXS data at different temperatures. A modified Gibbs-Thomson equation is employed to predict the lamellar thickness from DSC data, giving results consistent with those derived from SAXS.