| 초록 |
This paper reports the study of the influence of castor oil (CO) and cashew nut shell liquid (CNSL) on the non-isothermal cure behavior of epoxy resin using differential scanning calorimetry (DSC). At all heating rates studied, an increase in the temperature for maximum rate of cure and a drop in the enthalpy of cure has been noted with the addition of CO. The energy of activation evaluated using Kissinger method and Ozawa methods have shown a decreasing trend with addition of CO. As CNSL is found to act as a hardner for epoxy resin, epoxy curing by CNSL also has been studied with and with out hardner. In the absence of hardner, a single step cure has been noted and addition of CNSL. An increase of temperature for maximum rate of cure, enthalpy and energy of activation has been observed for this case. In the presence of hardner and CNSL, the cure of epoxy has been found to be proceeding by a two step process; the cure at low temperature due to hardner and that at high temperature due to CNSL. Also it has been found that with increasing loading of CNSL, enthalpy of curing due to hardner has been reduced while that due to CNSL, increased. Similarly the temperature for maximum rate of cure due to hardner has been slightly reduced and that due to CNSL is increased. All these results present a competitive cure behavior occurring in epoxy resin containing CNSL in the presence of hardner. |
