초록
The effects of different phenol-novolac resin contents and curing temperatures on isothermal cure kinetics of epoxy (diglycidyl ether of bisphenol-A)/ phenol-novolac/BPH (N-benzylpyrazinium hexafluoroantimonate) blend system were studied on a differential scanning calorimeter (DSC). Latent properties of blend system initiated by BPH, a cationic initiator, were analyzed at different temperatures by measuring the conversion as a function of curing time in isothermal DSC analysis. The BPH in this blend system appears to act as a thermally latent initiator. The isothermal cure kinetics of blend system using BPH suggest an autocatalytic kinetic mechanism, but vitrification occurs at higher conversions and curing becomes diffusion controlled. The kinetic rate constants, $k_1\;and\;k_2$ of blend system increased with increasing content of phenol-novolac resin at a fixed curing temperature, but the reaction order, m and n were independent of the phenol-novolac resin content and the curing temperature. The activation energies, $E_{a,1}$ and $E_{a,2}$ obtained from Arrhenius plot decreased with phenol-novolac resin content in the 20~40wt% range.
