Novel method to determine autocatalytic cure kinetics model constants of dual-reaction thermosets

Analysis of the cure kinetics of dual-reaction thermosets requires the determination of nine constants including the ratio of the first reaction to the total reaction. Simultaneous determination of the nine constants from experimental data is extremely challenging because an objective function to determine the constants through regression analyses is a sum of two highly non-linear kinetic functions. This paper proposes a novel method to determine all nine constants accurately and consistently using minimum testing data. The method first utilizes a model-free analysis for the ratio. An analytical least-squares approach is followed for the remaining eight model constants of dual reactions. The method is implemented for a highly-filled dual-reaction epoxy-based underfill commonly used in advanced semiconductor packaging applications. The proposed method is remarkably efficient; it requires data from only two standard DSC dynamic scans to determine the nine constants accurately. The robustness and accuracy of the proposed method are corroborated experimentally.