Studies on the intermolecular structural heterogeneity of a propylene-ethylene random copolymer using preparative temperature rising elution fractionation

Authors

  • Yonggang Liu,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
    Search for more papers by this author
  • Shuqin Bo,

    Corresponding author
    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
    • State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
    Search for more papers by this author
  • Yejuan Zhu,

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
    Search for more papers by this author
  • Wenhe Zhang

    1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China
    Search for more papers by this author

Abstract

The intermolecular structural heterogeneity of a propylene-ethylene random copolymer was studied by preparative temperature rising elution fractionation combined with GPC, 13C-NMR, differential scanning calorimetry, and wide-angle X-ray diffraction analysis of the obtained fractions. The isotacticity of fractions increased with increasing elution temperature, and the ethylene content decreased monotonously. Fitting of the obtained comonomer triad sequences by Bernoullian and first-order Markovian statistical models indicated that lower isospecific active sites are more active toward ethylene. The isolated ethylene unit disrupted the crystallizable isotactic sequence and lowered the crystallizability of the polypropylene chain. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 232–239, 2005

Ancillary