Abstract：To solve the problems existed in the ternary intumescent flame retardant system, such as hydrophilicity and heterogeneity in particle size and mixing, intumescent flame retardant powders were surface modified by wet ball milling with silane coupling agent KH-550. FTIR, XRD, TGA, SEM were used to analyze and characterize modified flame retardant powders. The results show that by wet ball milling silane coupling agent KH-550 can be successfully grafted on the surface of the intumescent flame retardant. The surface modification of intumescent flame retardant powders with KH-550 improves their dispersibility and compatibility with polymer matrix, and 3 h is the best modification time.

Keywords：wet ball milling; silane coupling agent; surface modification; intumescent flame retardant