Combustion Performance And Fire Risk Assessment Of Flame Retardant PVC Material

Poly(vinyl chloride) (PVC) is widely used in wire and cables, building materials, electrical components, etc. The high plasticizer content of PVC during processing makes it less resistant to ignite and burn, and a large amounr of toxic and harmful gases are produced when PVC is forced to burn. Therefore, the addition of smoke suppressants is necessary when PVC is used, and zinc hydroxystannate(ZHS) could be used as a comprehensively effective flame retardant in PVC.Preparation of flame retardants was carried out in accordance with procedures reported in the literature for the flame retardants ZHS. In this work, the author treated PVC with ZHS and the incorporation of ZHS with inorganic flame retardants, then the combustion performance was studied. Finally, fire risk of flame retardant materials was evaluated based on the test results of cone calorimeter (CONE). The conclusions of this paper are as follows:(1) The uniform and high purity ZHS was synthesized by co-precipitation method at room temperature. The results of combustion performance indicated that the prepared sample of ZHS could improve the flame retardant properties of PVC significantly; The results of thermal analysis indicated that the initial decomposition temperature was reduced, the temperature range during the stabilization phase was increased, and the exothermic peak of DTG curve was significantly increased when ZHS was added; The results of combustion characteristics indicated that the risk of heat and smoke of PVC were reduced when ZHS was added. It can be seen that hollow ZHS cubes could improve the flame retardancy of PVC more effectively than ZHS spheres, and that there may be associated with the poor thermal stability and excessive inward etching of ZHS spheres. The photo of carbon residue after CONE test could prove the highly effective flame retardancy of ZHS,and it also indecate the carbon residue of ZHS spheres was more dense than hollow ZHS cubes.(2) Studying the flame retardancy of ZHS and its composite flame retardant found that ZHS/AbiO3 can significantly improve the LOI value. TGA test found that the binary composite systems narrowed the temperature range of initial decomposition of PVC, and a significant increase in the temperature range of the stabilization phase, and significantly reduced the initial pyrolysis temperature of PVC (PVC/ZHS/MRP except). But ZHS/Sb2O3 was not conducive to the promotion of charring or the suppression of smoking. ZHS/MRP increased the initial pyrolysis temperature of PVC, and significantly increased the temperature range of the stabilization phase.The mixed flame retardant of PVC/ZHS/Sb2O3/MoO3, those had more efficient on flame retardancy and smoke suppression of PVC. When compared with PVC/ZHS/Sb2O3 and PVC/ZHS/ZB, PVC/ZHS/Sb2O3/MoO3 increased the initial decomposition temperature of PVC, and narrowed the temperature range of initial decomposition, and the quantity of carbon residue was increased, the results above proved that MoO3 could significantly change the pyrolysis way of PVC.(3) The effects of ZHS and its composite flame retardant on the combustion performance of PVC were evaluated by cone calorimeter instrument. From above results it can be seen that pure PVC had the highest risk of hot and smoke; ZHS could be used as a comprehensively effective flame retardant in PVC; The risk of fire spread^ hot and smoke of PVC/MRP were the lowest, but the toxicity hazard of smoke of PVC/MRP was the highest. PVC/ZHS/Sb2O3/MoO3 had the lowest risk of flashover, and it’s hot and smoke risk was relatively low, but the toxicity hazard of smoke was relatively high. The risk of hot and smoke danger is low for PVC/ZHS/MoO3, but the smoke parameter values was relatively high, it was not conducive to the fire escape and evacuation of personnel. PVC/ZHS/ZB/MoO3 and PVC/ZHS/ZB were not helpful to reduce the danger of hot and smoke, but PVC/ZHS/ZB/MoO3 could significantly reduce the toxicity hazard of smoke. The fire risk of PVC and it’s composite flame retardant materials had been deduced basised of analytic hierarchy process(for building use), from above results it can be seen that the fire hazard of PVC/ZHS was the lowest. PVC/ZHS/MoO3 and PVC/ZHS/Sb203/Mo03 followed, the comprehensive fire risk of PVC/ZHS/ZB and PVC/ZHS/ZB/MoO3 were relatively high, and PVC/ZHS/MRP was in the middle position.