Effects of a silane coupling agent on the exfoliation of organoclay layers in polyurethane/organoclay nanocomposite foams?

Mi Sun Han, Youn Hee Kim, Sung Jae Han, Seok Jin Choi, Sang Bum Kim, Woo Nyon Kim

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

An attempt was made to synthesize polyurethane (PU)/organoclay nanocomposite foams with high thermal insulation properties. The organoclay was modified by polymeric 4,4′-diphenylmethane diisocyanate (PMDI) with a silane coupling agent. The structure of the organoclay-modified PMDI with the silane coupling agent was determined by Fourier transform infrared spectroscopy and nuclear magnetic resonance. Transmission electron micrographs and wide-angle X-ray diffraction patterns showed that the interlayer distance increased for the PU/organoclay nanocomposites with the addition of the silane coupling agent. It was expected that the distance between the organoclay layers would increase and that the organoclay would be dispersed on a nanoscale in the PU matrix because of the organic/inorganic hybrid bond formation between the organoclay and silane coupling agent. Compressive and flexural strengths of the PU/silane coupling agent/organoclay nanocomposite foams were similar to those of the PU/organoclay nanocomposite foams. However, the thermal conductivity appreciably decreased from 0.0250 to 0.0230 W/m h°C in the PU/silane coupling agent/organoclay nanocomposite foams. Scanning electron micrographs showed that the cell size of the PU/silane coupling agent/clay nanocomposite foams also decreased. On the basis of these results, it is suggested that the smaller cell size and lower thermal conductivity of the PU/silane coupling agent/organoclay nanocomposite foams were mainly due to enhanced exfoliation of the organoclay layers by the silane coupling reaction.

Original languageEnglish
Pages (from-to)376-386
Number of pages11
JournalJournal of Applied Polymer Science
Volume110
Issue number1
DOIs
Publication statusPublished - 2008 Oct 5

Keywords

  • Nanocomposites
  • Organoclay
  • Polyurethanes

ASJC Scopus subject areas

  • Materials Chemistry
  • Polymers and Plastics
  • Surfaces, Coatings and Films
  • Chemistry(all)

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