Thermo-oxidative stability of polypropylene/layered silicate nanocomposites

Zita Dominkovics, József Hári, E. Fekete, B. Pukánszky

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Several series of experiments were carried out to check the effect of components on the stability of PP/layered silicate nanocomposites. The amount of organophilic montmorillonite (OMMT) changed between 0 and 6, while that of maleated polypropylene (MAPP) between 0 and 50 vol%. The composites were prepared in an internal mixer at 190 °C. Mixing speed and time were changed to study the effect of processing conditions on stability. The structure of the samples was characterised by various methods, while stability by the induction time of oxidation (OIT), the onset temperature of degradation (OOT) and by colour. Contrary to numerous claims published in the literature, which indicate the positive effect of layered silicates on the stability of polymer nanocomposites, our results clearly proved that both OMMT and MAPP accelerate degradation during processing and deteriorate the properties of PP composites. Residual stability decreases drastically with increasing amounts of both components, chain scission leads to the decrease of viscosity and to inferior strength and deformability. In spite of expectations, the effect of the components is independent of each other. Discoloration is caused mainly by the inherent colour of the filler and it decreases with increasing exfoliation. The most probable reason for decreased stability is the reaction of the components with the stabilisers, but this explanation needs further verification. Processing conditions influence degradation considerably, increasing shear rate and longer residence times lead to more pronounced degradation. The basic stabilization of commercial grade polypropylenes is insufficient to protect the polymer against degradation and without additional stabilization processing under normal conditions results in products with inferior quality.

Original languageEnglish
Pages (from-to)581-587
Number of pages7
JournalPolymer Degradation and Stability
Volume96
Issue number4
DOIs
Publication statusPublished - Apr 2011

Fingerprint

Silicates
Polypropylenes
polypropylene
silicates
Nanocomposites
nanocomposites
thermal stability
degradation
Degradation
Bentonite
montmorillonite
Processing
Clay minerals
Polymers
Stabilization
stabilization
discoloration
Color
color
Discoloration

Keywords

  • Antagonism
  • Layered silicate
  • Nanocomposites
  • Polypropylene
  • Thermo-oxidative degradation

ASJC Scopus subject areas

  • Polymers and Plastics
  • Materials Chemistry
  • Mechanics of Materials
  • Condensed Matter Physics

Cite this

Thermo-oxidative stability of polypropylene/layered silicate nanocomposites. / Dominkovics, Zita; Hári, József; Fekete, E.; Pukánszky, B.

In: Polymer Degradation and Stability, Vol. 96, No. 4, 04.2011, p. 581-587.

Research output: Contribution to journalArticle

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