Composite nanoarchitectonics with ionic clay nanofillers-embedded polypropylene for efficient flame retardance

The widely used flame-retardants (FRs) are of brominated ones with hazardous characteristics. Therefore, developing an eco-friendly FRs is important to maintain the safety upon large scale usage. Such a flame retardant was made using polypropylene (PP) by integrating ionic nanofillers ((layered double hydroxide, LDH; and cationic clay (Mica)) together. They were modified with stearate (SA) and cetyltrimethylammonium (CTA) respectively to be compatible with PP. For this, initially they were separately made by co-precipitation and ion-exchange reactions, then dispersed in xylene together and mixed with PP/xylene. The SA-LDH content was 1 wt % and CTA-Mica similar to 3 wt%. TEM showed that exfoliated 2D organo-clays were uniformly dispersed in PP nanocomposites enhancing thermo-mechanical strength than pristine PP. The peak heat release rate (PHRR) of pristine PP was decreased by SA-LDH and CTA-Mica, corresponding to 58% reduction. Additionally, for PP nanocomposites, more char residues were remained; suggesting that PP nanocomposite as an efficient FRs.

Automated summary

In this study, an eco-friendly flame retardant was developed using polypropylene and ionic nanofillers, which were able to enhance the thermo-mechanical strength and significantly reduce the peak heat release rate of the original polypropylene.