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Electrical and thermal properties of composite of liquid crystalline polymer filled with carbon black
Author(s) -
Wong Y. W.,
Lo K. L.,
Shin F. G.
Publication year - 2001
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.1993
Subject(s) - materials science , electrical resistivity and conductivity , carbon black , composite material , anisotropy , percolation threshold , composite number , percolation (cognitive psychology) , thermal conductivity , polymer , thermal conduction , thermal , thermodynamics , physics , natural rubber , quantum mechanics , neuroscience , biology
The electrical resistivity and thermal conductivity of a liquid crystalline polymer (LCP) filled with a commercial carbon black (CB) of various volume fractions (ϕ) is investigated. The percolation threshold (ϕ c ) is found at about 3%, and the resistivity (ρ) as a function of (ϕ − ϕ c ) satisfies the exponential function. Although the pure LCP is highly anisotropic in thermal and mechanical properties after processing, the composite samples exhibit no preferential direction for electrical conduction. Samples of ϕ below ϕ c exhibit a negative temperature coefficient of resistivity while those above ϕ c show almost no temperature dependence from room temperature to 200°C. In addition, the samples at lower ϕ have higher thermal conductivity in the LCP flow direction than those measured in the transverse and thickness directions, and they approach the same value at higher ϕ. This result indicates that preferential molecular alignment of the matrix LCP is responsible for the behavior of the thermal conductivity of the composites. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1549–1555, 2001