Research on the related properties of EVM/Al(OH)3/SiO 2 composites applied for halogen-free flame retardant cable insulation and jacket

摘要

The halogen-free flame retardant (HFFR) ethylene-vinyl acetate copolymer (EVM)/ATH/SiO_2 composites have been prepared by melting compounding method, and the flame retardant, thermal stability, rheological, electrical, and mechanical properties have been investigated by cone calorimeter, LOI, UL-94, TG, FE-SEM, rotational rheometer, dielectric breakdown, and ultimate tensile. The results indicate that the flame retardant of EVM vulcanizates is improved and the fire jeopardizing is dramatically reduced due to the addition of ATH. It is necessary that sufficient loading of ATH (≤120 phr) is needed to reach essential level (LOI > 30; V-0 rating) of flame retardant for HFFR EVM/ATH/SiO_2 composites used as cable in industry. The rheological characteristics show that at all the measurement frequencies, the storage and loss modulus of the composites increase monotonously as the concentration of ATH filler increases, while the complex viscosity and tan delta present reverse trend. And also, it has been found that the HFFR composites at high filler concentrations still keep good mechanical and electrical properties, which is very important for practical applications as cable.