Silanized-silicon/epoxy nanocomposites for structural capacitors with enhanced electrical energy storage capability

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• 作者：Weixing Sun^a ; Hongchao Wu^a ; Xiaoli Tan^a ; Michael R. Kessler^b ; Nicola Bowler^a ; ^{nbowler@iastate.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：A. Si nanoparticles ; Silane surface treatments ; A. polymer-matrix composites ; B. electrical properties ; Structural capacitors
• 刊名：Composites Science and Technology
• 出版年：2015
• 出版时间：16 December 2015
• 年：2015
• 卷：121
• 期：Complete
• 页码：34-40
• 全文大小：2743 K

文摘

The surface treatment of Si nanoparticles (nano-Si) by silane coupling agents is shown to contribute to improved dispersion of nano-Si in an epoxy matrix, leading to a 25% increase of dielectric breakdown strength, a 38% increase in dielectric constant, and no significant increase in loss tangent at 10 wt.% silanized-Si loading, compared to neat epoxy, over a wide temperature range. The extremely low loss tangent of these polymer-matrix nanocomposites is observed over a wider frequency range (10⁻² to 10⁶ Hz) than previously reported. The silanization of Si nanoparticles also doubles the maximum filler loading and simplifies the fabrication process of the nanocomposite. Additionally, silanized-Si imparts a higher dielectric breakdown strength (E_br) than that of the pristine Si filled nanocomposite at the same nanofiller loading, contributing to an increased energy storage capability. Furthermore, the introduction of 10 wt.% silanized nano-Si increases the storage modulus of epoxy by 40% at 30 °C and the glass transition temperature shows preserved thermal stability. Silanized Si/epoxy nanocomposites can therefore be regarded as promising candidates for structural capacitors in engineering systems.