| Summary: | Polyurethane (PU) is one of the industrially important polymers which offers a combination
of unique properties and meets a wide range of demanding application. Electrical
conductivity and dielectric properties of polyurethane/graphite composites were
investigated in this paper. Moisture Cured Polyurethane was prepared with varying
NCO/OH ratio 2.0, 2.2 and 2.4 by polyoxytetramethylene glycol (PTMO) Mw 2000 and
Toluene diisocyanate (TDI). Graphite powder of 0 to 12.5 vol% was dispersed in PU to
form electro conductive composites. Percolation concentrations were determined to be as
(9±1), (9±2) and (10±3) vol. % for the NCO/OH ratio of 2.0, 2.2 and 2.4 respectively. It
shows that percolation concentration does not have significant change as the NCO/OH ratio
increases. The dielectric properties of the composites were investigated in the frequency
range of 1 KHz to 10MHz. It was found that PU composites became electro-conductive
when filled with 9 to 10.0% of the filler and support well the dc conductivity results.
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