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Expanded graphite–epoxy composites with high dielectric constant
Author(s) -
Xie YunChuan,
Yu DeMei,
Min Chao,
Guo XiuSheng,
Wan WeiTao,
Zhang Jing,
Liang HongLu
Publication year - 2009
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.29741
Subject(s) - composite material , materials science , dielectric , epoxy , diglycidyl ether , graphite , percolation threshold , loss factor , dielectric loss , relaxation (psychology) , bisphenol a , electrical resistivity and conductivity , psychology , social psychology , electrical engineering , optoelectronics , engineering
Composites of an expanded graphite/diglycidyl ether of bisphenol A (DGEBA) were prepared by a simple melt blending method, and their dielectric and mechanical properties were investigated. During observations of fractured surfaces of the composites, the graphite sheets were seen to be homogeneously dispersed in the epoxy matrix. Moreover, the composites presented an enhanced dielectric constant (∼ 180) and a low loss factor (∼ 0.05) at 50 Hz, suggesting their potential suitability for embedded dielectric applications. The enhanced dielectric constant can be explained by the percolation theory and the relatively low loss factor was attributed to strong interfacial interactions between the polymer molecules and the OH/COOH groups of the expanded graphite, which constrained the orientational polarization of the polarons. Furthermore, dynamic mechanical analysis of the composites showed a restricted macromolecular relaxation and improved mechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009