Controlling porosity in bridged polysilsesquioxanes through elimination reactions

Mark D. McClain, Douglas A. Loy, Sheshasayana Prabakar

Research output: Contribution to journalConference articlepeer-review

8 Scopus citations

Abstract

The retro Dieis-Alder reaction was used to modify porosity in hydrocarbon-bridged polysilsesquioxane gels. Microporous polysilsesquioxanes incorporating a thermally labile Diels-Alder adduct as the hydrocarbon bridging group were prepared by sol-gel polymerization of trans-2,3-bis(triethoxysilyl)norbornene. Upon heating the 2,3-norbornenylene-bridged polymers at temperatures above 250 °C, the norbornenylene-bridging group underwent a retro Diels-Alder reaction losing cyclopentadiene and leaving behind a ethenylene-bridged polysilsesquioxane. Less than theoretical quantities of cyctopentadiene were volatilized indicating that some of the diene was either reacting with the silanol and olefinic rich material or undergoing oligomerization. Both scanning electron microscopy and nitrogen sorption porosimetry revealed net coarsening of pores (and reduction of surface area) in the materials with thermolysis.

Original languageEnglish (US)
Pages (from-to)277-282
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume435
StatePublished - Dec 1 1996
Externally publishedYes
EventProceedings of the 1996 MRS Spring Symposium - San Francisco, CA, USA
Duration: Apr 8 1996Apr 12 1996

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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