Flame retarded polyethylene/wood flour composites with high performances: Satisfying both sides with intumescent flame retardants and synergistic compatibilizers, respectively

WPC is inflammable that threatens the safety of life and property. To reduce the risk of conflagration, it is important to make WPC flame retardant. But the flame retarded WPC is usually highly loaded which deteriorates its mechanical properties. It is difficult to satisfy both sides. In this article, we make attempt to prepare the flame retarded polyethylene/wood flour (WF) composites with high mechanical properties by using an ammonium polyphosphate and phosphorus based intumescent flame retardants (IFR) system. To maintain the high performances of the flame retarded composites, the multi‐monomer graft copolymers are synergistically used as the interfacial compatibilizers for the composites. Cone calorimeter testing, UL94 flame tests, limited oxygen index (LOI) and thermogravimetric analysis (TGA) are used to evaluate the flammability properties and thermal stability of the composites. Results show that WF enhances the flame retardancy of the composites with the help of suitable IFR system. The coordination of flame retardants with WF content is an effective measure to control the fire spreading and the risk of combustion. The incorporation of flame retardants transforms the role of WF from the inflammable material into the charring agent of IFR system. By using the IFR system, a highly flame retarded composite with V0 classification based on the vertical combustion testing was successfully prepared. With the help of the synergistic compatibilizers, it is possible to prepare an intumescable flame retarded rPE/WF composites with high performances. The incorporation of WF, and flame retardants can improve the thermal stability of the composites. POLYM. COMPOS., 39:569–579, 2018. © 2016 Society of Plastics Engineers