Synthesis Of Modifided Silica And Research Of Flame Retardant Property In Polyethlene

Due to the good electrical insulation, mechanical properties and long-lastingcorrosion resistance, Polyethylene can be applied to aerospace industry, transport andtextiles, which has a broad application prospects. However, due to the low limitingoxygen index of polyethylene, which belongs to flammable materials, its applicationrange is restricted. Therefore, to explore the green and efficient synthesis of a flameretardant additive has become a research hotspot. In this paper, different metal ornon-modified mesoporous MCM-41as a flame retardant additive has been perparedthrough hydrothermal method and post-treatment method. And the thermalnano-polymer composite degradation performance of the polyethylene matrix compositematerial is characterized by thermal gravimetric method.By using hydrothermal synthesis method and post-treatment method, the differentelements （Fe, S, Ni, Pt） modified MCM-41is synthesized, porous materials arecharacterized detailedly by means of XRD, FT-IR, N₂adsorption and SEM, TEM.Analysis of the content of different atoms and their effects on the pore structure andmorphology of modified mesoporous material are given. XRD patterns and SEMimages show that the other-elements grafted mesoporous pore degree of its order andmorphology are not changed, are still the long-range ordered hexagonal mesoporousstructure, but the lattice parameter increases and mesopores become smaller to someextent; mesoporous form in the presence of heteroatoms and heteroatom content in themodified zeolite were identified by using FT-IR spectra and ICP analysis. FromM-MCM-41pore size distribution curves and TEM images, it can be seen that the poresof mesoporous are about3⁵nm, distribution evenly and orderly.The synthesized MCM-41and M-MCM-41are added into the polyethylene andsyntheticed polymer nanocomposites. We focus on the effects of different additives onthe flame retardancy of polyethylene,finding that polyethylene nanocompositessynthesized with Fe-MCM-41have the best performance in flame retardancy, make themaximum thermal degradation temperature of polyethylene decrease from the original500°C to503°C, delay the decomposition of polyethylene, but carbon residuedecreases largely at600°C; Ni, S, Pt-modified MCM-41, to a certain extent, reduce therate of decomposition of polyethylene, but the effects are not obvious. The initialdecomposition temperature of S-modified polyethylene MCM-41increases from449°Cup to455°C, but the maximum temperature of thermal degradation becomes lower. The maximum mass loss rate of Ni-MCM-41is43.73%, decreases12.31%comparing withthe unmodified poly ethylene with the maximum mass loss rate of56.04%.The catalyticperformance of Pt itself is very good, but the Pt-MCM-41does not promotepolyethylene to catalyst into carbon, the amount of carbon residue does not increase at600°C. On the contrary, it speed up the rate of decomposition of the polymer matrix,thus the performance of flame retardant has not been significantly improved.