Zinc Borophosphate Ammonium and Its Effects on the Burning Properties of Wood Flour/Polyvinyl Chloride Composites

A zinc borophosphate ammonium compound (ZBP) was synthesized by the boric acid ′flux′ method, the structure, morphology and composition of the sample were characterized by XRD, SEM, XPS, FTIR and TGA analyses. Then it was added as a flame retardant to wood flour polyvinyl chloride composites (WF/PVC), and the flame retardant WF/PVC composites were obtained by hot pressing process. Thermogravimetric analysis (TG) and cone calorimeter (CONE) were used to analyze the pyrolysis and combustion properties of ZBP-WF/PVC composites. The mechanical properties of the composites were tested by universal mechanical testing machine and combined impact tester. TG results showed that the addition of flame retardants improved the thermal stability of the composites and increased the residual carbon content. CONE test showed that the addition of flame retardants had little effect on the heat release of the composites, but it significantly reduced the smoke release rate of the materials and endowed WF/PVC composites with a certain flame retardance and smoke suppression capability. Mechanical results showed that the flame retardant with 10% addition had little effect on the mechanical properties of the composites.