Study On EG Synergy APP/CFA/SiO₂Expansion Flame Retardant To Flame-retardant HDPE And Wood Plastic Composite

In recent years, ploymer materials have been used in many fields of people’s life. WPC is a novel material, which is composed of flammable wood fiber and thermoplastics, has been extensively applied to several realm. But the application of ploymer materials and WPC is limiited due to their flammability, so it is important to improve the flame retardancy of these two materials.In this acticle, EG and APP/CFA/SiO2intumescent flame retardant was employed to enhance the flame retardancy of HDPE and WPC. Limited oxygen index (LOI), cone calorimeter, thermogravimetric analysis(TGA), scanning electronmicroscope (SEM) and mechanical testing machine were used to study warious performance of flame retardant materials.The results of different ratio EG and APP/CFA/SiO2flame-retarded HDPE showed that in the compounded system, an increase in the LOI value was observed with the additive amount of EG increasing. The LOI value of composite materials contained10%EG was higher than the one added5%EG. When the additive amout of flame retardant reached30%and10%EG was added, the LOI value reached31.3%and the UL-94test passed V-0level. But the LOI of the one that contained30%EG and APP/CFA/SiO2alone were only25.8%and29.4%, respectively. The result indicated that there is synergistic effect between EG and APP/CFA/SiO2. The addition of EG and APP/CFA/SiO2could effectively improve the weight-loss temperature of HDPE and increase the char residue after combustion, which is of positive significance for the flame retardancy of materials. It was possiblely due to the viscous materials producted by the decomposition of APP/CFA/SiO2adhered to the surface of intumescent char after the combustion of EG, which could effectively bind the intumescent char, made the arrangement of the char more compact and continuous, had the effect of separating heat and cutting off oxygen more effectively and showed better flame retardant efficiency. In the compounded system, the mechanical properties of material contained5%EG was better than the one contained10%EG at the same content of flame retardant. With the content of EG increasing, the machanical properties of materials was worsen.The results of EG and APP/CFA/SiO2flame-retarded HDPE-based WPC showed that in the compounded system, as the content of EG increasing, the LOI value increased first, then decreased. When added9%EG, the LOI value reached32.2%and the UL-94test passed V-0level. But the LOI of the one that contained30%EG and APP/CFA/SiO2alone were only28.1%and27.9%, respectively. The result indicated that there is synergistic effect between EG and APP/CFA/SiO2. When the content of EG was a relatively low number, the mechanical properties of composite materials were improved. But with the content of EG increasing, the machanical properties of materials was worsen. The addition of EG and APP/CFA/SiO2could effectively improve the weight-loss temperature of HDPE-based WPC and increase the char residue after combustion, which is of positive significance for the flame retardancy of materials. It was possiblely due to the viscous materials producted by the decomposition of APP/CFA/SiO2adhered to the surface of intumescent char after the combustion of EG, which could effectively bind the intumescent char, made the arrangement of the char more compact and continuous, had the effect of separating heat and cutting off oxygen more effectively and showed better flame retardant efficiency.