Silicone filled halloysite nanotubes for polypropylene composites: Flame retardancy, smoke suppression and mechanical property

The halloysite nanotubes (HNTs-Si) was filled with poly-siloxane and introduced into polypropylene (PP) composite containing intumescent flame retardants (IFR) in order to simultaneously improve the fire performance and mechanical properties. The fire behavior investigation indicated that the peak heat release rate and the peak smoke release rate of PP/IFR sample containing HNTs-Si were reduced by 31% and 26% respectively compared with that of the PP/IFR sample containing HNTs. The elongation at break was greatly increased by the presence of HNTs-Si. The charring mechanism analysis suggested that HNTs-Si was capable of keeping the original tube structure and twisting with degraded PP chains to form fiber-like compact char layers in the high temperature range. Consequently, the combination of HNTs-Si and IFR exhibited excellent heat and smoke suppression during the combustion of PP composite. This work has proved that HNTs-Si is an effective synergist in producing flame retardant PP composites with comprehensive properties.

Automated summary

By introducing halloysite nanotubes (HNTs-Si) into polypropylene (PP) composite containing intumescent flame retardants (IFR), the fire performance and mechanical properties were simultaneously improved. The presence of HNTs-Si reduced the peak heat release rate and peak smoke release rate, while greatly increasing the elongation at break. The combination of HNTs-Si and IFR exhibited excellent heat and smoke suppression during combustion, proving to be an effective synergist in producing flame retardant PP composites with comprehensive properties.