Enhanced thermal stability and flame retardancy of polystyrene by incorporating titanium dioxide nanotubes via radical adsorption effect

Titanium dioxide nanotubes (TNTs) were synthesized by a hydrothermal method and then incorporated into polystyrene (PS) through in situ bulk radical polymerization. In comparison, the PS/TiO2 composites with various TiO2 loadings were also prepared by melt blending method. The addition of TNTs induced a significant thermal stabilization on PS: with the 5 wt% loading of TNTs, the corresponding T−10% and Tmax of the composite were improved by 41 and 58 °C compared to those of pristine PS. Meanwhile, an approximately 33% reduction in peak heat release rate was observed in the case of PS/TNTs5%. In contrast, TiO2 did not exhibit so effective enhancement in thermal stability and flame retardancy as TNTs. Direct pyrolysis-mass spectrometry and thermo-gravimetric analysis/infrared spectrometry analysis showed that the radical adsorption effect of TNTs was responsible for the improved thermal stability and flame retardancy of polystyrene.