Mathematical modeling of temperature rising elution fractionation (TREF) of polyethylene and ethylene/1-olefin copolymers

Abstract

Temperature rising elution fractionation (TREF) is a characterization technique widely used to estimate chemical composition distribution (CCD) of semicrystalline copolymers. Although several mathematical models have been previously proposed to elucidate the TREF fractionation mechanism, all previous TREF models assume equilibrium fractionation; thus, they cannot describe important kinetics effects observed in TREF experiments. In this work, a new TREF model is developed incorporating crystallization and dissolution kinetic models during the fractionation process. The proposed model describes the effects of molecular weight, comonomer content, cooling rate, heating rate, and solvent flow rate on experimental TREF profiles for both polyethylene and ethylene/1-olefin copolymers very well. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.