Structures and properties of intramolecular flame-retardant PET fibers

Intramolecular flame-retardant PET resins were prepared via copolymerization reaction by using reactive halogen-free flame retardant CEPPA as a third monomer and then melt spun into flame-retardant PET fibers.The phosphorus content analysis of the flame-retardant PET resins by elementary analysis and NMR showed that the majority of CEPPA were directly reacted into the PET chains.The crystallinity,dyeing behavior,mechanical properties and flammability of the flame-retardant PET fibers were also investigated.The results showed that the crystallinity of the fibers was decreased as increasing the phosphorus content,which led to the improved dyeing properties of the fibers.The dye-uptake of the fibers with disperse dyes under atmosphere pressure and at boiling temperature dyeing was above 90%.Moreover,the flame-retardant PET fibers exhibit superior flame retardance and improved anti-dripping property,with the limiting oxygen index(LOI) value above 35%.