Study On The Synergistic Flame Retardancy Of Iron Oxide And Ammonium Polyphosphate On Wood Plastic Materials

In the study of flame retardancy of polyurethane foam wood plastic composite?FWPC?,adding a single flame retardant often causes a large amount of smoke production,so it is necessary to pay attention to the problem of large smoke production while improving the flame retardancy of the materials.The flame retardancy,smoke suppression,mechanical strength,change of aging color difference,heat stability and microstructure effects of different proportions APP and Fe2O3 on the FWPC were investigated.The mechanism of APP and Fe2O3 on the flame retardancy and smoke suppression of FWPC was explored.The results of the study show that:?1?With the addition of 2 wt%Fe2O3 and 18 wt%APP,the ignition time?TTI?of the sample could be delayed by 66.7%,the peak heat release rate?PHRR?decrease by 39.8%,and the effective combustion heat?EHC?decreases by 12.6%.The residual carbon becomes more compact and hard after cone calorimetry,it showed that adding a certain proportion of Fe2O3 and APP had obvious effect on the flame retardance of FWPC,indicating that the addition of a certain proportion of Fe2O3 and APP to FWPC is obvious.?2?When adding 3 wt%Fe2O3 and 17 wt%APP,the total smoke release?TSR?,total smoke production?TSP?and specific extinction area?SEA?decreased by 38.2%,37.4%,and 27.1%respectively.At the same time,the smoke density value decreased with the increase of Fe2O3 and showed the lowest smoke density value.Thus,it was concluded that Fe2O3 and APP could reduce tobacco production to a great extent,and have synergistic effect of smoke suppression.The addition of Fe2O3 to APP/FWPC significantly reduced the yield of CO,indicating that Fe2O3 could modify APP and had obvious attenuated effect based on APP/FWPC.?3?When Fe2O3 and APP are added to FWPC,the decomposition temperature is higher than control sample,especially the residual carbon amount of 2 wt%Fe2O3 and 18 wt%APP samples is up to 65%,indicating that the suitable proportion of Fe2O3 and APP can provide the flame retardancy effect of condensed phase,thus improving the thermal stability of FWPC.The addition of Fe2O3 and APP can help to improve the compressive strength of FWPC and the water absorption of 24 h.Fe2O3 has a certain ultraviolet shielding effect on FWPC,and the color difference of samples tends to be stable with time increasing.?4?The analysis of the micromorphology of the samples showed that the addition of F₂eO₃improved the uniformity between the components,especially the improvemnent of the coating effect oAPP/polyurethane on wood powder. The carbon layer of the sample with 2 wt%F₂eO₃ and 18 at% APPis the most compact and contimuous.Fourier transform infrared spectroscopy?FTIR? showed thatadding F₂eO₃ and APP can affect the structure of carbon functional group.