| With the times and technological advances in science flame retardant materials, the emphasis increasingly increased on efficiency and environmental issues. Polypropylene(PP) is a very important general-purpose resins, and due to its widely used in various sectors, the fire-retardant requirements are also increasing. Intumescent flame retardant system in recent years has become one of the hotest areas of flame retardant, which has the advantage of very prominent, such as efficient and environmentally friendly. Intumescent flame retardant system in a number of complex nano-layered silicates, metal oxides can improve the flame retardant properties of the composites, showing excellent synergy. Thus, the expansion flame retardant synergistic combination of significance for the study of flame retardant polymer is very important.The bentonite is from Liaoning Province, we prepared fine processing organic bentonite(OMMT) after a series of excellent performance, and determine the optimum parameters of the process. We study the kind and amount of modifier’s influnce for the modified bentonite and its mechanism. The study found reactive modifiers caprolactam by forming amide ions between the layers are arranged so that the layer spacing increases. Rather than reactive modifier is to rely on long-chain organic layer arranged between the layers to increase spacing,and different arrangements for different interlayer spacing increasing extent; composite modified due to the different modifiers into the inter-layer there is competition, so that the extent of the interlayer spacing increase as good as a single modifier.Organobentonite(OMMT) was applied to form PP/layered nano-silicates composites.And through the study of the combustion behavior of composite clear OMMT flame-retardant effect. This illustrated that OMMT had a flame retardant effect on PP, but it can not be up to the requirements of the flame retardant materials.We choose OMMT as synergists, and intumescent flame retardant ammonium polyphosphate(APP)/dipentaerythritol(DPER) complex prepared intumescent flame retardant PP, the effects of OMMT composites flame retardant properties and through the study of the thermal degradation behavior of the composite material to explore its mechanism. It was found that the synergy OMMT and expansion can be further improved flame retardant PP oxygen index, help composite materials to reduce heat release rate, increase the amount of carbon residue,besides, OMMT achieve this synergy by affecting APP thermal degradation.We use APP as acid source, DPER as carbon source, organic bentonite, a metal oxide as synergist, with the PP melt blending to form an expanded flame complex system. Based on thesynergistic effect of layered nano silicate and metal oxide, Zn O、Fe2O3、Cu O containing OMMT were obtained by ion-exchange method. Compared with the PP, the oxygen index of PP/OMMT(Fe2O3) increased 3 units, the peak of heat release rate has decreased by 26%.This illustrated that OMMT and OMMT(Fe2O3) both had a flame retardant effect on PP, and the flame retardant effect of OMMT(Fe2O3) is higher than OMMT, but none of them is up to the requirements of the flame retardant materials. Incorporating OMMT(Zn O)、OMMT(Fe2O3)、OMMT(Cu O) with APP/DPER into PP, the synergistic effect of modified OMMT was investigated. We use thermogravimetric, infrared, X-ray photoelectron spectrum, X-ray diffraction and scanning electron microscope analyses to study the retardant properties of composites. Studies have shown that, OMMT(Zn O), OMMT(Fe2O3), OMMT(Cu O) exhibit superior than OMMT on synergistic flame retardant, and the metal oxide work on the synergistic flame retardant by varying the pyrolysis process APP.The above results laid the experimental foundation for the preparation of organic bentonite, and prepared a new type of high efficient flame retardant synergistic agent, which enriched the study of the mechanism of synergistic effect expansion, and provided a theoretical reference for the expansion of flame retardant PP. |
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