New Aminophenylsilsesquioxanes—Synthesis, Properties, and Epoxy Nanocomposites

Kunio Takahashi; Santy Sulaiman; Joshua M. Katzenstein; Stephanie Snoblen; Richard M. Laine

doi:10.1071/CH06153

RESEARCH ARTICLE

New Aminophenylsilsesquioxanes—Synthesis, Properties, and Epoxy Nanocomposites

Kunio Takahashi ^A ^C , Santy Sulaiman ^B , Joshua M. Katzenstein ^A , Stephanie Snoblen ^A and Richard M. Laine ^A ^B ^D

+ Author Affiliations

- Author Affiliations

^A Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109-2136, USA.

^B The Macromolecular Science and Engineering Center, University of Michigan, Ann Arbor, MI 48109-2136, USA.

^C Nippon Shokubai Co., Osaka 564-8512, Japan.

^D Corresponding author. Email: talsdad@umich.edu

Australian Journal of Chemistry 59(8) 564-570 https://doi.org/10.1071/CH06153
Submitted: 8 May 2006 Accepted: 8 July 2006 Published: 8 September 2006

Abstract

New aminophenylsilsesquioxanes, dodecaaminophenylsilsesquioxane (NH₂PhSiO_1.5)₁₂ (DAPS), and hexadecaaminooctaphenylsilsesquioxane ((NH₂)₂PhSiO_1.5)₈ (HDAPS), were prepared from dodecaphenylsilsesquioxane (PhSiO_1.5)₁₂ (DPS), and octaphenylsilsesquioxane (PhSiO_1.5)₈ (OPS), by nitration in fuming HNO₃, followed by reduction with HCO₂H/Et₃N/Pd/C. The effects of the cage structure and numbers of NH₂ groups on the chemical and physical properties of these compounds were compared with octaaminophenylsilsesquioxane (NH₂PhSiO_1.5)₈ (OAPS), and analogous epoxy resin nanocomposites. The cage structure does not affect nitration patterns (primarily meta and para), but affects coefficients of thermal expansion (CTEs), likely because of overall crosslink densities and because of the epoxy tether structures joining cube vertices. CTEs as low as 25 ± 2 ppm°C^–1 were found, perhaps the lowest reported for an unfilled epoxy resin. The thermal stabilities of synthesized HDAPS epoxy nanocomposites were 20–30°C lower than those made with OAPS. This result may be a consequence of less-complete curing due to gelation before stoichiometric curing, caused by the much higher crosslink densities in OAPS.

Acknowledgments

Thanks to Nippon Shoakubai Co., Delphi Automotive Systems, and Air Force Research Laboratories, Wright–Patterson Air Force Base (AFRLWPAFB) through a subcontract on SBIR Phase II Contract FA8650–05-C-5046 to Materials Inc., for support of this work. We also thank Professor H.-J. Chen for early work on this project, but note this work was published without permission of the current authors.^[²¹^] TGMX was a gift from Dr R. Bashir of Delphi Automotive Systems, and a portion of the dodecaphenylsilsesquioxane was a gift from Hybrid Plastics.

References

New Aminophenylsilsesquioxanes—Synthesis, Properties, and Epoxy Nanocomposites

Abstract

Acknowledgments

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