羟基锡酸钴在软质聚氯乙烯中的高效阻燃消烟作用

通过共沉淀法制备了亚微米尺寸的羟基锡酸钴（CHS）阻燃剂，并将其应用于软质聚氯乙烯（PVC）中，制得CHS/PVC复合材料。采用极限氧指数仪（LOI）、锥形量热仪、TG和拉伸仪研究了CHS/PVC复合材料的阻燃性能、热稳定性和力学性能。结果表明，CHS可以有效提高CHS/PVC复合材料的阻燃性能，并对CHS/PVC复合材料的力学性能保护较好；与空白PVC相比，当CHS添加量（CHS与PVC质量比）为10%时，CHS/PVC复合材料的LOI增加了2.3%，热释放速率峰值和烟释放速率峰值分别下降了39.6%和57.4%。这主要是由于CHS受热后脱除的水具有冷却和稀释热量的作用；另一方面在燃烧过程中生成的CoCl₂可以有效催化PVC早期分解，形成更加致密且连续的残炭，从而有效抑制PVC的燃烧。

High efficient flame retardancy and smoke suppression effect of cobalt hydroxystannate on flexible polyvinyl chloride

Submicrometer-sized cobalt hydroxystannate (CHS) flame retardant was prepared via coprecipitation method and applied to flexible polyvinyl chloride (PVC) to obtained CHS/PVC composites. The flame retardancy, thermal stability and mechanical properties of CHS/PVC composites were investigated by limiting oxygen index (LOI), cone calorimeter, TG analysis and universal tensile tests. The results show that the CHS effectively enhances the flame retardancy and maintains the mechanical property of CHS/PVC composites. Compared with blank PVC, when the mass ratio of CHS to PVC is 10%, the LOI of CHS/PVC composite is increased by 2.3%, the peaks of heat release rate and smoke production rate are reduced by 39.6% and 57.4%, respectively. The enhancement for CHS/PVC composites in flame retardation mainly attributes to the water dehydration from CHS when heating which dilutes heat. On the other hand, the CoCl₂ generated during the combustion process can effectively catalyze the early decomposition of PVC and then a denser and continuous residual charlayer is formed, thereby the combustion of PVC is effectively suppress.