Fire-retardant poly(ethylene terephthalate) by combination of expandable graphite and layered clays for plastics and textiles

Expandable graphite (EG) and polyethylene terephthalate (PET) were melt blended to develop a new nanocomposite intumescent flame retardant in which the effect of combination of EG with nanoclays would be exploited with sodium and organo-modified montmorillonites, namely Cloisite®Na, Cloisite®10A and Cloisite®30B. X-ray diffraction analysis coupled to transmission electron microscopy and rheology shows that PET-EG-clay compounds are characterized by an exfoliated and/or intercalated morphology as a function of the type of clay. Thermal stability of composites is enhanced in nitrogen and air by filler adding as compared with neat PET, while combustion rate is decreased both in the bulk material and in textiles made of fibers spun from the compound.