Effects of Curing Agent and Curing Temperature on Material Properties of Epoxy/BaTiO3 Composite Embedded Capacitor Films

Epoxy/BaTiO₃ composite embedded capacitor films (ECFs) were fabricated using dicyandiamide (DICY) as a curing agent and 3-(4-chlorophenyl)-1,1-dimethylurea as a curing accelerator to investigate the curing behavior and material properties of the ECFs with different curing systems and curing temperatures. The curing behaviors of the ECFs with three different curing systems were identified using differential scanning calorimeter analysis. The chemical structure changes of the ECFs were analyzed using Fourier transform infrared (FT-IR) spectroscopy. The intensity changes of a carbonyl peak in the FT-IR with different curing temperatures indicated that cyclization and hydrolysis reactions increased as curing temperature increased. In addition, the effect of this chemical structure change according to curing temperature was investigated in terms of glass transition temperature (T_g), peel adhesion strength, and coefficients of thermal expansion. In the case of the ECF with low DICY content, the degree of cure increased as curing temperature increased and the improvement in the material properties of the ECF with low DICY content resulted mainly from the increase in the degree of cure. The material properties of the ECF with curing accelerator improved after the degree of cure reached 100% due to the low DICY amount and the addition of curing accelerator. However, the material properties of the ECF with high DICY content did not show improvement as curing temperature increased, because the dominance of the two primary amines of the DICY to cure promoted the cyclization and hydrolysis.