The cure kinetics of off-stoichiometric biphenyl epoxy (4,4-diglycidyloxy-3,3',5,5'-tetramethyl biphenyl)-dicyclopentadiene type phenolic resin system by differential scanning calorimetry(DSC) using an isothermal approach were investigated. The epoxy/hydroxyl (E/H) ratios of stoichiometric (E/H = 1), excess phenol off-stoichiometric (E/H = 0.8) and excess epoxy off-stoichiometric (E/H = 1.2) of epoxy and phenolic group were selected and all kinetic parameters of the cure reaction including the reaction order, activation energy and the rate constant were calculated and reported. To describe the curing reaction after the vitrification controlled by diffusion factor, the semiempirical relationship proposed by Chern and Poehlein and the calculated parameters were used. A one-to-one relationships, which is independent of the cure temperature, between the glass transition temperature and the fractional conversion were interpreted using DiBenedetto equation. Time-Temperature-Transformation (TTT) isothermal cure diagram has been established at each equivalent weight ratio using the kinetic model coupled with diffusion factor and the DiBenedetto equation.

등온 differential scanning calorimetry(DSC)를 이용하여 biphenyl계 에폭시 수지 (4,4-diglycidyloxy-3,3'',5,5''-tetramethyl biphenyl)와 dicyclopentadiene type phenolic resin(DCPDP)와의 비화학량론적 에폭시 수지 조성물의 경화반응을 검토하였다. 에폭시와 경화제의 당량비(epoxy/hydroxyl ratio)를 0.8, 1.0, 및 1.2로 변화시켰으며, 반응차수, 활성화에너지, 속도상수를 포함한 모든 반응속도 파라미터들을 계산하였다. 반응속도 모델과 Chern과 Pohlein이 제안한 반실험식을 이용하고 계산된 파라미터 값을 적용함으로써 유리화 이후 발생하는 확산에 의한 경화반응을 예측할 수 있었다. DiBenedetto 방정식으로부터, 측정된 유리전이온도와 전화량과는 경화온도에 무관한 일대일 관계가 성립함을 알 수 있었고, 확산을 고려한 반응속도식과 DiBenedetto 방정식을 이용하여 Time-Temperature-Transformation(TTT) 등온경화도표를 작성할 수 있었다.

Keywords: biphenyl epoxy resin; dicyclopentadiene type phenolic resin; off-stoichiometry; cure kinetics; TTT isothermal cure diagram