Study on the curing kinetics of an epoxy encapsulant by DSC method

Due to the excellent insulating strength and mechanical properties, epoxy encapsulants are widely used in aerospace industry, electrical engineering, and electronic devices, etc. However, the residual stress derived from the curing process hinders the full display of its potential in many applications. In this paper, the curing kinetics of an epoxy encapsulant was studied by differential scanning calorimetry (DSC) method. The non-isothermal DSC results show that, the curing exothermic peak shifts to higher temperatures with the increment of heating rate, and the total reaction heat is about 371 J/g. The isothermal DSC results show that, with the increment of curing temperature, the curing exothermic peak intensity increases significantly and the curing time becomes much shorter. Based on the results, a phenomenological kinetic model, which could effectively fit the curing rate vs. curing degree experimental curves in a wide temperature range, was proposed to analyze the kinetic behaviors of the epoxy encapsulant.