Microencapsulated of Ammonium Polyphosphate and Its Flame Retardance with Synergistic MCM-41 Fillers in Natural Rubber

Microencapsulated with ammonium polyphosphate (MCAPP) with epoxy resin (EP) was prepared by in situ polymerization. The effect of mesoporous silica MCM-41 as a synergistic agent on the flame retardancy of intumescent flame retardant natural rubber (NR/APP) and microencapsulation flame retardant natural rubber (NR/MCEP-APP) composites were studied using limiting oxygen index (LOI) and UL-94 tests, their mechanical properties were evaluated by dynamic mechanical thermal analysis (DMTA) as well as physico-mechanical properties. It was found that the LOI value of the NR/MCEP-APP was higher than the values of the NR/APP and NR composite. In comparison with the NR/MCEP-APP composite, the LOI values of the NR/MCEP-APP/MCM-41 composite were increased, and UL-94 ratings of most ternary composite were raised to V-0. A synergistic effect was observed between MCM-41 and MCEP-APP in NR composites. Incorporating MCEP-APP together with MCM-41 enhanced mechanical properties and flame retardancy of the NR resin.

Keywords: Intumescent flame retardant; Synergism; DMTA; mechanical properties