The Study Of The Flame Retardant, Smoke Suppression And Thermal Degradation Properties Of Ethylene Vinyl Acetate/Layered Double Hydroxides Based On Red Mud Composites

Red mud is bulk solid waste produced from alumina industry. Its utilization hasbeen a hot issue of academia and industrial research. In this paper, layered doublehydroxides (LDH) were synthesized based on red mud through the introduction ofdivalent magnesium ions and carbonate ions combind with a calcination-rehydrationmethod, and characterized using X-ray diffraction (XRD). The LDH based on redmud as flame retardant is applicable to ethylene-vinyl acetate copolymer (EVA), theirperformances including flame retardant, smoke suppression and thermal degradationwere increased by the choosing of a suitable compound flame retardant and a surfacecoating. The flame-retardant, smoke suppression and thermal degradation propertieswere studied by cone calorimeter test (CCT), scanning electron microscopy (SEM),smoke density test (SDT), thermogravimetry-fourier transform infrared spectroscopyspectrometer (TG-IR) and others. The mechanism of flame retardant and smokesuppression was explored through the analysis of experimental results. The results areas follow(1) XRD results confirmed that LDH was synthesized successfully using red mudas the raw materials through the introduction of divalent magnesium ions andcarbonate ions combined with a calcination-rehydration method.(2) In this thesis, the flame retardant, smoke suppression and thermal degradationperformances of LDH based on red mud were compared with those of aluminumhydroxide (ATH) and magnesium hydroxide (MH) in EVA material. The resultsconfirm the feasibility of LDH based on red mud as new efficient flame retardant and smoke suppressant.(3) In this paper, the graphite powder and the nitrogen and phosphorus flameretardants were compound with LDH in the different proportions, and then were madeinto a composite material combined with EVA. The flame retardant, smokesuppression and thermal degradation performances of the composite material werestudied. The experimental results demonstrate that adding an appropriate proportionof graphite powder and the nitrogen and phosphorus flame retardant can effectivelyimprove the flame-retardant, smoke suppression and thermal degradationperformances of the composite materials.(4) In this paper, LDH was modified by the coating of zinc hydroxystannate (ZHS),and the interaction between LDH substrate and ZHS coating was studied by X-raydiffraction (XRD), scanning electrom microscopy (SEM), transmission electronmicroscopy (TEM) and energy dispersive spectrdmeter (EDS). The results proved thatLDH was successfully coated by ZHS. When the modified LDH was applied to EVAmaterial, the flame retardant, smoke suppression and thermal degradation propertiesof the composites are increased sificantly. This result should be ascribed to the goodflame and smoke suppression of ZHS.(5) In this thesis, the study of LDH as a a flame retardant in EVA materialsprovides an efficient way to the utilization of red mud and confirms that the feasibilityof LDH as an efficient flame retardant in the EVA material.