Investigating The Catalysis Of Solid Catalysts On The Char Formation And Flammiablity Of Polypropylene

Catalyzing flame retardation belong to an approach in which the direction of the combustion reaction of polymer is changed to evolve more non-combustible materials by the addition of low amount of catalysts in polymer matrix, thus in which the flammiability and thermal stability of polymer are improved. At present, with increasing of the environmental consciousness, the application of halogen flame retardant and some other flame retardant are limited. Catalyzing flame retardation has become one of promising approach in future. In this paper, from the point of catalytic carbonization of polymer, we reported tow kinds of flame retadant system by catalyzing carbonization of polymer, which characterized by the lower loading and higher char yield, and so on. Details as follows:1. The influence of addition of Ni2O3, three kind of charring catalysts and acid-treated charring catalysts on char formation and flammiability of PP was investigated. Flame retardant measurement results show that when adding carbon black, silicon dioxide and inflation graphite into PP/Ni2O3 composites the char yield is relative low. However when adding the acid-treated carbon black, silicon dioxide and inflation graphite (SXGO) into PP/Ni2O3 a high-yield char formation was obtained. In these materials, the SXGO was demonstrated to be a most effective charring catalyst. Flame-retardant results indicate that the highest char yield and the best flame retardancy of PP materials could be obtained with the composition of PP materials (PP/SXGO/Ni2O3:92/3/5). The morphologies and structures of the char obtained are examined by scanning electron microscopy (SEM),transmission electron microscopy (TEM) and X-ray powder diffraction (XRD), and the char formation mechanism are analyzed further.2. In this work, multi-metal catalyst was prepared by combustion. The effects of the content of three metal compounds on the char yield were discussed. Results indicate that when the motal ratio is Mo/Ni/Mg=0.1/5/1, the char yield of composite was the highest. The morphologies and structures of multi-metal catalysts are examined by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD), and the active constituent of multi-metal catalys mechanism are analyzed further.The catalytic effects of Ni/Mo/Mg catalyst (Nmm-cat) on the flammability and thermo-stability of polypropylene was investigated. The PP/Nmm-cat composites were prepared by the melt mixing in a Brabendermixer. The conversion rate of carbonization was evaluated by a model experiment. The flammability and thermal-stability of composites were characterized by cone calorimeter and thermogravimetric analysis (TGA). The results show that the flammability and thermal-stability of PP/Nmm-cat composites are improved dramatically at the low loading in PP.