A compound with boron and phosphorus towards epoxy resin with excellent flame retardancy, smoke suppression, transparency, and dielectric properties

This work presents a novel approach to enhance the flame retardancy and dielectric properties of epoxy resin (EP) through the incorporation of a newly developed flame retardant (POSB) containing phosphorus and borate. The EP composite with only 5 wt% POSB achieves an impressive limiting oxygen index (LOI) of 32.9 % and attains a V-0 rating in the UL-94 test. Cone calorimetry results reveal a substantial reduction of 33.3 % in peak heat release rate (pHRR) and 36.7 % in peak smoke production rate (pSPR) for the EP/POSB sample compared to the control EP sample. The impact of POSB on mechanical and dielectric properties is comprehensively analyzed, demonstrating minimal impact on tensile, impact, and flexural performance, as well as transparency in the EP sample. Notably, the EP/5 wt% POSB composite exhibits significantly decreased dielectric constant and dielectric loss in the frequency range of 103 ∼ 106 Hz. This research introduces a strategy of producing materials for electronic products with simultaneous improvements in flame retardancy, dielectric properties, mechanical performance, and transparency.