title: Considerable different frequency dependence of dynamic tensile modulus between self-heating (Joule heat) and external heating for polymer--nickel-coated carbon fiber composites.
abstract: Dynamic tensile moduli of polyethylene--nickel-coated carbon fiber (NiCF) composites with 10 and 4 vol % NiCF contents under electrical field were measured by a homemade instrument in the frequency range of 100--0.01 Hz. The drastic descent of the storage modulus of the composite with 10 vol % was verified in lower frequency range with elevating surface temperature (T(s)) by self-heating (Joule heat). The composite was cut when T(s) was beyond 108 °C. On the other hand, the measurement of the composite with 4 vol % beyond 88 °C was impossible, since T(s) did not elevate because of the disruption of current networks. Incidentally, the dynamic tensile moduli by external heating could be measured up to 130 and 115 °C for 10 and 4 vol %, respectively, but the two composites could be elongated beyond the above temperatures. Such different properties were analyzed in terms of crystal dispersions, electrical treeing, and thermal fluctuation-induced tunneling effect.
authors.affiliation: Department of Polymer Material Science, Faculty of Chemical, Environmental and Biological Science, and ‡Department of Electrical and Electronics Engineering, Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology , Dalian 116024, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Yuezhen
authors.initials: Y
authors.lastname: Bin
authors.forename: Enyuan
authors.initials: E
authors.lastname: Dong
authors.forename: Masaru
authors.initials: M
authors.lastname: Matsuo