Triple Silicon, Phosphorous, and Nitrogen-Grafted Lignin-Based Flame Retardant and Its Vulcanization Promotion for Styrene Butadiene Rubber.

In this study, we present an innovative environmental silicon-, phosphorus-, and nitrogen-triple lignin-based flame retardant (Lig-K-DOPO). Lig-K-DOPO was successfully prepared by condensation of lignin with flame retardant intermediate DOPO-KH550 synthesized via Atherton-Todd reaction between 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and γ-aminopropyl triethoxysilane (KH550A). The presence of silicon, phosphate, and nitrogen groups was characterized by FTIR, XPS, and P NMR spectroscopy.