| Popis: |
The cyclic thermoresistive response of individual carbon nanotube yarns (CNTYs) embedded into epoxy resins is investigated. The influence of the temperature at which the epoxy resin cures on the thermoresistive response is investigated by using two epoxy resins, one that cures at room temperature and the other one that cures at 130 °C. Heating-cooling cycles ranging from room temperature (RT, 25 °C) to 80 °C, incremental cycles (RT to 40 °C, RT to 60 °C and RT to 80 °C) and incremental heating-dwell cycles are applied to monofilament composites, while their electrical resistance is simultaneously recorded. The monofilament composites showed a negative temperature coefficient of resistance during the heating-cooling cycles of -7.07x10-4 °C-1 for specimens cured at high temperature, and -5.93x10-4 °C-1 for specimens cured at room temperature. The hysteresis after the different heating-cooling cycles was slightly smaller for specimens cured at 130 °C, in comparison to specimens cured at room temperature. Several factors including the intrinsic thermoresistivity of CNTY, level of infiltration and the effect of curing temperature may explain the thermoresistive sensitivity of the monofilament composites. |
