High Temperature Thermal Field-Flow Fractionation for the Characterization of Polyethylene

Abstract

A thermal field-flow fractionation device has been constructed in which the cold wall can be held above 100°C. The apparatus is described. Preliminary results are given which illustrate the retention of polyethylene and polypropylene. Details are provided of preliminary experiments intended to determine the molecular weight averages and molecular weight distribution of a National Bureau of Standards polyethylene sample, SRM 1484. The lack of monodisperse, well-characterized calibration standards is considered a major problem. Nonetheless, good agreement is found with published values for number average and weight average molecular weight.