Kinetics of structure formation in PP/layered silicate nanocomposites

J. Hári, Z. Dominkovics, E. Fekete, B. Pukánszky

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Polypropylene (PP)/organophilized montmorillonite (OMMT) and polypropylene/organophilized montmorillonite/maleic anhydride grafted polypropylene (MAPP) composites were prepared in an internal mixer under a wide range of processing conditions to study the kinetics of structure formation. Structure and properties were characterized by a variety of techniques. The gallery structure of the organophilic silicate changed in spite of the fact that no compatibilizer was added to PP/OMMT composites. Silicate reflection shifted towards smaller 2θ angles, broadened and its intensity decreased indicating intercalation. Transmission electron microscopy (TEM) micrographs even showed individual platelets at long mixing times. However, the extent and direction of changes in the gallery structure of the silicate did not justify those observed in properties. The analysis of the results and additional experiments proved that the degradation of the polymer also takes place during processing leading to the formation of carbonyl and/or carboxyl groups, as well as to the decrease of molecular weight. The modification of the chain structure of the polymer influences interfacial interactions and the intercalation process. Some properties are directly determined by molecular weight (rheological properties, elongation). Both the clay and the MAPP seem to accelerate degradation. Thermooxidative degradation must have disadvantageous effect during the application of PP nanocomposites and needs further study.

Original languageEnglish
Pages (from-to)692-702
Number of pages11
JournalExpress Polymer Letters
Volume3
Issue number11
DOIs
Publication statusPublished - Nov 1 2009

Keywords

  • Gallery structure
  • Layered silicate
  • Nanocomposites
  • Polypropylene
  • Thermal degradation

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry

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