Study On Surface Fire-retardant Wood Plastic Composites

Wood plastic composite (WPC) was easy to burn which greatly limited its application. The flame resistance of WPC was studied when intumescence fire-retardant coating was coated on its surface. Four aspects were included in this research:1) the components and the volume of the components in the flame retardant systems were determined; 2) the effects of expansible graphite and mica on the flame retardant systems were analyzed; 3) the influence of resin, pigments and fillers to the flame retardant systems were focused; 4) analyzed the mechanism of the IFRC.Based on the thesis, the following conclusions are drawn:(1)When the dosage of APP, MEL, PER is respectively 6g,3.5 g,2g, best result comes out, with the fire resistance-time reaching 1500s; and the best effect appeared when the total content of fire retardant is around 50%; the fire resistance-time of WPC has a quadratic growth relationship with the coating weight.(2)Expansible graphite and mica can enhance the strength and density of the char layer formed in the combusting process which greatly reduced the mass loss and increase the fire resistance-time to 1920s and 2184s respectively after they are included into the system of APP-MEL-PER; the water resistance and color retention of the coating are also improved due to their insoluble properties.(3)Compared with epoxy resin and epoxy resin modified by organic silicone, the comprehensive property of IFRC based on acrylic resin is the best.(4)The oxidation process of the char layer is greatly alleviated when Fe2O3 or filler was mixed into the APP-MEL-PER system.(5)The pyrolysis reaction of the IFRC can be divided into five stages; the reaction activation energy and mechanism of each phase are not the same. The first and the fourth stage belong to the two-dimensional diffusion model; the second stage belongs to 3d diffusion model D3; the third and the fifth phase conform to the chemical reaction series model RO (1.5) respectively.