Investigation of Track and Thermal Shock Crack Resistance in Outdoor Cycloaliphatic Electrical Insulating Materials Using Response Surface Methodology

Epoxy resin samples were prepared using cycloaliphatic resin and anhydride curing agents. Response Surface Methodology (RSM) was applied to determine the effect of five independent variables (Silbond W12EST, MoldXA400, CSR, PC1000 and BYK3701) at 5 levels on the dependent variables thermal shock crack resistance (TSR) and track resistance. 33 experimental samples were prepared according to experimental design made by RSM. It was observed that not only an increase in the amount of MoldX A400 in the compound improved the tracking, but also amount Silbond W12EST had positive effect on it. The results showed that if the total filler amount in the formulation is lower than 60% the time-to-track is less than 300 min, even with using a high amount of MoldXA400 (30%). Increasing the amount of Silbond W12EST as well as core-shell toughening agent (CSR) microparticles can improve the TSR because of crack propagation inhibition caused by particles. On the other hand, an increase in MoldX A400 deteriorated TSR due to the creating weak bonds with epoxy matrix.