Preparation of boron nitride hybrid containing phosphorus and silicon and its effect on flame retardant, smoke suppression, and thermal conductivity properties of styrene‐butadiene rubber

Abstract In this study, a nanofiller (M‐DOPO‐BN) was synthesized by surface modification of hexagonal boron nitride with vinyltrimethoxysilane (KH‐171) and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), and compounded with aluminum diethyl phosphinate (ADP) to study their effects on flame retardant, smoke suppression and thermal conductivity properties of styrene‐butadiene rubber (SBR). The results showed that the composites with an ADP content of 20 parts per hundred of rubber (phr) have good flame retardant properties, but the total smoke production increased significantly. The flame retardant properties of SBR composites compounded with 3 phr M‐DOPO‐BN and 17 phr ADP were not only further improved, but also the peak carbon monoxide production rate (pCOP) and peak carbon dioxide production rate (pCO 2 P) were reduced by 37.0% and 67.5%, respectively, compared with pure samples, showing a good smoke inhibition effect. In addition, the thermal conductivity of the composites have also been improved to a certain extent. The variable temperature infrared and residual char analysis of SBR composites showed that the reasons for its flame retardancy and smoke suppression are that M‐DOPO‐BN can catalyze the formation of carbon, and the silica and boron nitride generated by decomposition during combustion can improve the density of residual char.