Low-Cost Preparation of High-k Expanded Graphite/Carbon Nanotube/Cyanate Ester Composites with Low Dielectric Loss and Low Percolation Threshold

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• 作者：Lei Cao ; Wei Zhang ; Xinhua Zhang ; Li Yuan ; Guozheng Liang ; Aijuan Gu
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：February 19, 2014
• 年：2014
• 卷：53
• 期：7
• 页码：2661-2672
• 全文大小：733K
• ISSN：1520-5045

文摘

Expanded graphites (EGs) or modified EGs (eEGs) were blended with multiwalled carbon nanotubes (MWCNTs) in a big weight ratio to prepare low-cost composites, coded as (EG-MWCNT)/cyanate ester (CE) or (eEG-MWCNT)/CE. The structures and properties of the composites are closely related to the loading of total conductors (f). When f < 0.75 wt %, EGs are beneficial for preparing high-k composites with low dielectric loss; however, when f 鈮?1.05 wt %, eEGs have superior advantages. When f = 1.5 wt %, the dielectric constant and loss of (eEG-MWCNT)1.5/CE composite are about 1.6 and 0.6 times that of the (EG-MWCNT)1.5/CE composite, respectively. The origin behind these interesting results was intensively discussed. Attractively, (EG-MWCNT)/CE and (eEG-MWCNT)/CE composites have similar percolation thresholds, so the surface modification of EGs does not increase the percolation threshold; moreover, ternary composites prepared herein have much better dielectric properties than both traditional EG/CE and MWCNT/CE composites.