硅酸盐对软PVC阻燃性和热性能的影响

研究了硅酸盐对软聚氯乙烯(PVC)的阻燃作用。通过热分析法研究了经阻燃处理后软PVC从室温到800℃的热降解过程;通过剩炭率的测定,结合用扫描电子显微镜(SEM)对样品燃烧后剩炭结构的观察,探讨了硅酸盐的阻燃机理。结果表明:经硅酸盐处理的样品具有较高的氧指数(OI)和剩炭率,与未处理的样品相比具有较好的阻燃性能。硅酸盐的加入可改变PVC的热降解过程,使起始降解温度降低,最大失重速率加快,硅酸盐对软PVC的阻燃主要是由于凝聚相的Lewis酸催化作用以及高温下生成的玻璃体对剩炭的保护作用造成的。

Influence of Silicate on Flame Retardancy and Thermal Property of Flexible PVC

The silicates used as flame retardants for flexible poly (vinyl chloride) (PVC) were studied. The thermal degradation at from the ambient temperature to 800℃of flexible PVC treated with flame retardants was studied by thermal analysis. Their mechanisms of flame retardancy were discussed through the char yield test, combining with SEM to investigate the structure of charred residue. The results show that flexible PVC treated with flame-retardants gives a high OI and char yield, which indicate that the flame-retardant degree of the treated PVC is improved. The silicates can change the thermal degradation of PVC, decrease the degradation temperature of PVC and increase the maximum rate of the weight loss. The reasons are that the metal ions in silicates function as Lewis acid catalysts and the glass matter is formed at high temperature to protect the residual char.