Achieving high-temperature resistance and excellent insulation property of epoxy by introducing triazine ring structure

The rapidly growing third-generation wide-band-gap semiconductor electronic device industry urgently requires high-temperature-resistant packaging materials. However, the epoxy molding compound materials cannot suffer the high-temperature working condition due to the intrinsic molecular chain structure of epoxy materials (EP). In this paper, bisphenol A-type cyanate (BADCy) with triazine ring structure was introduced into EP to improve its heat resistance. The curing reaction as well as the curing mechanism has been clearly revealed for BADCy/EP with different contents of BADCy according to the Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC) results. In the whole copolymer system, the copolymer at higher BADCy concentration (50–60 mol%) achieved the highest crosslink density (12.8 × 10–3 mol/cm3), thus, showing excellent glass transition temperature (> 200 °C) and thermal decomposition temperature(T5% > 400 °C). The heat resistance and electrical insulation property of BADCy/EP system have been systematically investigated, and a balance between high heat resistance and good electrical insulation are achieved at 66 mol% BADCy content, where the glass transition temperature reaches 215 °C, which is 73 °C higher than that of the EP system of anhydride copolymer. The volume resistivity of 1.5 × 1015 Ω·m and dielectric constant of 3.3 is obtained, indicating excellent electrical insulation and dielectric properties of BADCy/EP. This work provides a facile and efficient strategy to improve the overall properties of EP by optimizing the molecular chain structure.