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A study on electrical and thermal conductivities of ethylene–octene copolymer/expandable graphite composites
Author(s) -
Svoboda Petr,
Theravalappil Rajesh,
Poongavalappil Sameepa,
Vilcakova Jarmila,
Svobodova Dagmar,
Mokrejs Pavel,
Blaha Antonin
Publication year - 2012
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.22192
Subject(s) - materials science , composite material , graphite , octene , percolation threshold , thermal conductivity , filler (materials) , electrical resistivity and conductivity , composite number , shore durometer , percolation (cognitive psychology) , copolymer , polymer , electrical engineering , engineering , neuroscience , biology
A series of ethylene–octene copolymer (EOC) composites have been prepared by melt‐mixing with different weight ratios of expandable graphite filler (0–50% by weight). Electrical conductivity [both alternating current (AC) and direct current (DC)] and thermal conductivity studies were carried out. Effect of filler loading and frequency on electrical conductivity was studied. DC conductivity has increased from 1.51 × 10 −13 S cm −1 to 1.17 × 10 −1 S cm −1 . Percolation threshold by DC and also AC methods was observed at about 16 vol% of the filler. Real part of permittivity was found to be decreasing with increase in frequency while conductivity was increasing. Thermal conductivity was also found to be increasing gradually from 0.196 to 0.676 Wm −1 K −1 which is about 245% increase. Graphite not only increases the electrical and thermal conductivities but at and above 40 wt%, also acts as a halogen‐free, environmental friendly flame retardant. Shore‐A hardness of EOC/graphite composites shows that even with high graphite loading, the hardness is increased from about 50–68 only so that the rubbery nature of the composite is not affected very much. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers