Microstructural characterization of propylene-butene-1 copolymer using temperature rising elution fractionation

Abstract

Propylene–butene-1 copolymer (PBC) prepared with a titanium catalyst system was fractionated by temperature rising elution fractionation (TREF) over a temperature range of 5–80°C. PBC was shown to have a wide composition distribution ranging between 12–47 mol % of butene-1. Most of the fractions showed nearly the same crystallinity regardless of the butene-1 content. However, the solubility of the crystalline parts, which turned out to be the driving force for the fractionation, varied over the butene-1 content. Evidence that PBC shows isomorphism was obtained by the analysis of fractionated polymers, using 13C nuclear magnetic resonance spectrometry, X-ray diffraction, differential scanning calorimetry, and gel permeation chromatography. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1493–1501, 1998