Exchange of chain-end functionalized polyolefins on the clay surface

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

This chapter discusses a unique chain-end functionalized polyolefin structure that contains a reactive terminal group for forming a strong interaction with clay surfaces, resulting in exfoliated polyolefin/clay nanocomposites. Two commercially important polymers, including isotactic polypropylene (PP) and poly(vinylidene fluoride) (PVDF), have been studied to illustrate the research idea and experimental results. The chemistry to prepare chain-end functionalized PP containing a terminal OH or NH3+Cl group involves metallocene-mediated propylene polymerization using rac-Me2Si[2-Me-4- Ph(Ind)]2ZrCl2/MAO complex in the presence of styrene derivatives (St-f) and hydrogen, which serve as the chain transfer agents. On the other hand, the chain end functionalized fluoropolymer is prepared by a specific borane control radical initiator that bears a reactive Si(OR)3 group that is directly transferred to the beginning of the polymer chain. Despite the extremely low concentration of the chain-end group in PP and PVDF polymers, the terminal OH, NH3+Cl, and Si(OR)3 groups show good accessibility and reactivity toward the clay surfaces and form hydrogen bond, ion-exchange the cations (Li+, Na+, etc.), and chemical bonding, respectively. Such strong interactions anchor the PP or PVDF chain to the clay surfaces. On the other hand, the remaining unperturbed end-tethered high molecular weight PP or PVDF tail exfoliates the clay layers. This exfoliated structure is maintained even after further mixing with pure neat PP or PVDF polymers.

Original languageEnglish (US)
Title of host publicationPolymer Nanocomposites
Subtitle of host publicationAdvances in Filler Surface Modification Techniques
PublisherNova Science Publishers, Inc.
Pages177-200
Number of pages24
ISBN (Electronic)9781617285646
ISBN (Print)9781608761258
StatePublished - Jan 1 2009

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Materials Science(all)

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