Abstract: Amorphous and spherical zinc hydroxystannate (ZHS) particles with different particle sizes were prepared by using sodium stannate and zinc sulfate as raw materials. A comparative investigation was conducted on the flame-retardant and smoke-suppressant properties, tensile strength and thermal degradation properties of poly(vinyl chloride) (PVC) based compounds containing these two types of ZHS, and the dispersibility of ZHS particles in the PVC matrix was studied. The results indicated that, compared with amorphous ZHS particles, the spherical ones have more positive influences on the flame-retardancy, smoke-suppressant, tensile properties of PVC compounds at the same loading of ZHS. The incorporation of ZHS also improved the char yield of PVC at the end of thermal degradation and reduced the initial decomposition temperature and peak temperature at the first weight-loss stage. The amorphous ZHS exhibited a more significant decline in these two characteristic temperatures. In addition, the amorphous ZHS presented a better dispersibility and a tighter combination with PVC matrix than the spherical one.

Key words: zinc hydroxystannate, poly（vinyl chloride）, flame retardancy