Preparation And Flame Retardant Properties Of Salix / Polystyrene Wood-plastic Composites

With the development of society,people’s demand for wood plastic composites is increasing,especially in the construction materials industry,transportation industry and product packaging industry.However,the flammable characteristics of wood-plastic composites limit their development and application.Therefore,this thesis uses expandable polystyrene and salix powder as raw materials to prepare flame-retardant wood-plastic composites.The specific contents are as follows:1.The effects of salix psammophila powder addition on the flame retardant properties,thermal insulation properties,sound insulation properties and mechanical properties of wood-plastic composites were investigated by using the preparation process of mold foaming.Finally,100EPS-PF/40WF was determined as the optimal formula,with the limiting oxygen index of 26.6%and the vertical combustion grade of V-1.2.On the basis of wood plastic composites,the effects of single addition and compound use of flame retardant MPP and EG on the flame retardant properties of wood plastic composites were investigated.The combustion performance test showed that the flame retardant effect of the compound flame retardant specimen was significantly better than that of the specimen added with a single flame retardant.When the amount of compound flame retardant was m（MPP:EG）=1:1,the limiting oxygen index of the specimen WPC/30（15MPP&15EG）reached 33.9%,the vertical combustion level reached V-0 level,the heat release rate,total heat release and total smoke production were significantly decreased,and the residual amount of carbon after combustion reached 23.2%.The mechanical properties test and thermal insulation test showed that the impact strength increased by 40.62J/m².The thermal conductivity increases slightly within an acceptable range.Therefore,the optimum flame retardant ratio was determined to be m（MPP:EG）=1:1.3.In order to solve the problem of smoke release and heat release of flame retardant wood plastic composites,Fe₂O₃was used as a synergistic flame retardant and smoke suppressant.The combustion experiment showed that the limiting oxygen index was improved after adding Fe₂O₃,and the vertical combustion grade was V-0.The cone calorimeter test data showed that the total heat release,total smoke production and total smoke release were all reduced.The total heat release and total smoke production of WPCF-2decreased the most,which decreased by 38.3%and 26.5%respectively compared with the blank specimen.Through the scanning electron microscope observation of the residual carbon,it was found that the formed carbon layer was dense and continuous.Fourier transform infrared spectroscopy was used to determine that iron ions contribute to the catalytic oxidation of incomplete combustion products,and partially convert CO into CO₂,which is relatively less harmful to human body,proving the flame retardant and smoke suppression mechanism of Fe₂O₃as a synergistic flame retardant and smoke suppressant.The mechanical test and thermal insulation performance test showed that the addition of a small amount of Fe₂O₃had a positive effect on the impact strength and thermal conductivity of wood-plastic composites.Finally,the formula of WPCF-2 was selected as the optimal formula.