The Preparation And Investigation Of The Flame-retarded Wood Flour-polypropylene Composites

Wood-plastics composites (WPC) are known as a new generation materials for several fields such as housewares. The flame retardancy of wood-plastics composites was an important problem due to the easy flammability of both wood flour (fibre) and plastics, and demanded of fire protection in their use. In this study, a new intumescent flame-retardant (ammonium polyphosphate modified with3-(Methylacryloxyl) propyltrimethoxy silane) and M-APP with other synergistic effects additives were filled into the WF/PP composites, and polypropylene grafted with m-isopropenyl-a,a-dimethylbenzyl-isocyanate (m-TMI) were used as good compatibilizers to improve the mechanical properties of the WF/PP composites. The aim of this work was to study the effects of M-APP and M-APP with other synergistic effects additives, whether or not they can improve the flame-retardant and mechanical properties the WF/PP composites were studied based on mechanical instrument, cone calorimetry, limiting oxygen index (LOI) test, vertical burning test, thermogravimetric analysis, dynamic rheological analysis and SEM.And M-APP as a flame retardant, enhances the mechanical properties, flame retardancy and thermal decomposition properties of WF/PP composites. The SEM photographs demonstrate that in the presence of M-APP, the residual char is more intumescent and solider, the results showed that M-APP has good compatibility and promoted char formation in WF/PP composites. when M-APP loading reach25%, the LOI of the composite improve reach30.7%, can reach UL-94flammability standard, V-0rating, systems can make more flame retardancy properties and have a higher thermal stability and mechanical properties.The synergistic flame retarding effect between M-APP and expandable graphite (EG) were investigated. EG made the mechanical properties decrease, with the M-APP content increaseed, the mechanical property of WF/PP composites improved, when the EG:M-APP=1:1, the mechanical property decreased not obviously. With the EG content increaseed, the flame retardancy of WF/PP composites improved effectively. Also from LOI results, we can see the EG:M-APP=1:1, the LOI value reached the best. It is very clear that a significant flame retardant effect was obtained with EG:M-APP=1:1treatment on WF/PP composites.The synergistic flame retarding effect between M-APP and flame retardants FRW, nanometer magnesium hydroxide, nanometer calcium carbonate on WF/PP composites respectively were investigated. The results showed that the flame retardancy of three different synergistic effects additives on the WF/PP composites had little effect, but the mechanical properties had been improved apparently. When the nanometer magnesium hydroxide content was12%, the tensile strength, flexural strength, impact strength improved respectively7.41%,10.21%and11.46%; when the nanometer calcium carbonate content was8%, the tensile strength, flexural strength, impact strength improved respectively13.87%,7.79%and11.26%, the comprehensive mechanical property of WF/PP composites were excellent.