Research On Preparation And Properties Of PP/WO Flame Retardant Composites

In this paper, firstly we study the wollastonite halogen-free flame retardant system, on the basis of improvement of the traditional halogen flame retardant to reduce the amount of halogenated flame retardants and improve various properties of the composites. Experiments mainly adopts mixing, through the twin screw extruder, cooling, granulation, using injection molding machine to make molding into standard spline, then tests the mechanical properties such as tensile strength, impact strength, SEM, TGA, thermal deformation and oxygen index (LOI) performance test, etc. The main results of this paper are as follows:In the flame retardant system of PP/DBDPE/Sb2O3, when the ratio of DBDPE/Sb2O3 is 1/2, the overall performance of the composite material is relatively better, and increases its usage, mechanics of materials and flame retardant properties have been improved, and when its dosage is 9/18 in the composite system, the oxygen index is 26. Keep the dosage of DBDPE/Sb2O3 in 9/18, adding bicumyl in the composite system, the oxygen index increased from 24 to 27. Associated with the increase of the amount of bicumyl, oxygen index unchanged, but the tensile strength and impact strength are increased, and the flow properties of the material is greatly enhanced.The research in wollastonite retardant of polypropylene indicates that if wollastonite added individually, the mechanical properties of polypropylene is degraded, and the oxygen index began to increase to 19 when added 30phr wollastonite. Mixing ratio wollastonite and magnesium hydroxide can be effectively balanced mechanical properties and flame retardant effect of the material. The larger the content of wollastonite is, the bigger the impact strength is, and the smaller the impact strength is. Adding MRP to the PP/Wo/Mg(OH)2 system can greatly improve the flame retardant performance of composite materials. Adding the DBDPE/Sb2O3 flame retardant system to PP/Wo system greatly enhance the flame retardancy of materials, the oxygen index reached to 28, and by adding MAH-g-PP, HSt etc., the mechanical properties of the composites has been greatly improved.The TG analysis showed that both wollastonite and Mg(0H)2 can improve the thermal decomposition temperature and residual carbon content. Adding the bicumyl, MAH-g-PP and HSt can improve the thermal stability of PP/DBDPE/Sb2O3 system. The MCC test indicate that adding bicumyl to the PP/DBDPE/Sb2O3 system can decrease the heat release rate and capacity of the composite material, then improve the flame retardant properties. By SEM observation, we found that the bicumyl, MAH-g-PP and HSt improved the burning effect of the composite material, and enhance the flame retardant properties.