Study On Flame Retardant Properties Of Expandable Polystyrene Wood-plastic Composites

With the rapid development of China's comprehensive strength and the safety awareness of ascension,the Chinese construction industry demand for wood plastic composite are also increasing.In order to meet domestic demand,this paper took expandable polystyrene and wood particle as matrix.Urea-formaldehyde resin emulsion and acrylic latex were used for coating.Melamine phosphate,aluminum phosphate,expandable graphite as flame retardants was used in this system.In the end,the novel type of wood plastic composite materials was prepared.The paper mainly carries out four parts of work,the detailed work is as follows:(1)In this part,the urea-formaldehyde resin was synthesized,and FTIR,curing time,viscosity and DSC characterization were carried out on the synthesized urea-formaldehyde resin,which proved that the synthesis of urea-formaldehyde resin was successful and suitable for application in this system.Secondly,a novel mold foaming process for the preparation of wood-plastic composites was initiated,and new wood-plastic composites with different ratio of raw materials were prepared.Through testing and evaluation of sound insulation,thermal conductivity and mechanical properties,the optimal ratio of raw materials with comprehensive performance was selected,which was 100EPS-UF/50WP.By testing the limit oxygen index,vertical combustion grade and thermogravimetry,the influence of wood particle on the combustion performance of wood-plastic composites was studied and analyzed.The LOI value of 100EPS-UF/50WP samples reached 26.3%,the vertical combustion grade passed V-1,and the residual carbon in thermal mass was increased to 8.8%.(2)Based on the optimal formula,the wood-plastic composites were treated with single component flame retardant(MPP)and two-component flame retardant(MPP/AHP).The composite was characterized by the limit oxygen index,vertical combustion test,cone calorimetry test and thermogravimetric test.The WPC/15MPP LOI value of the single-component flame retardant sample was 29.7%(± 0.3),the vertical combustion was rated V-0,and the total heat release and total smoke release were decreased to a certain extent.The optimal ratio of MPP/AHP was 12/3,the limit oxygen index was 33.5%(±0.2),and the heat release of the two-component flame retardant was further reduced compared with that of the single-component flame retardant and the residual carbon was increased.The surface of carbon residue was observed by electron scanning microscope and the flame retarding mechanism was analyzed in detail.(3)The acrylic latex as coated liquid formaldehyde-free release of wood plastic composite material was prepared,using single-component flame retardants(MPP)and a two-component flame retardants(MPP/EG)to deal with wood plastic composite,and the limit oxygen index of composite materials,vertical combustion grade,cone calorimeter,such as flame retardant performance characterization,optimizing the best proportion of 1:1,MPP/EG when composite materials to V-0 level,with a minimum of 10 flame retardant additives,limiting oxygen index was 26.9%(±0.2).The total amount of heat release,the rate of heat release and the total amount of smoke release were all greatly reduced.At the same time,the thermal conductivity,sound insulation and mechanical properties of the composite were tested.Flame retardants have a small negative effect on thermal conductivity and impact properties,and have a certain enhancement effect on static bending strength and elastic modulus.(4)The flame retardancy,thermal conductivity and mechanical properties of formaldehyde resin and acrylic latex as coated samples were compared to analyze the reasons for the influence of different emulsions on their properties.