Preparation of dyeing, flame retardant and anti-dripping polyethylene terephthalate fibers based on natural sodium copper chlorophyll dyeing and intercalation of phosphorylated sucrose fatty acid ester

As the largest synthetic fibers in the world, polyethylene terephthalate (PET) fibers have a wide range of applications. However, PET fibers are flammable fibers with serious droplet phenomenon during combustion, which has great potential safety hazards. To solve the issue, multifunctional PET fibers with dyeing, flame retardant and anti-dripping were developed in this work. First, dyed PET fibers (DY-PET) were prepared by directly dyeing of PET fibers with sodium copper chlorophyllin (SCC). Then, DY-PET was intercalated with ammonium phosphate of sucrose fatty acid ester (APSFA) to obtain the flame retardant PET fibers (FR-PET). Compared with the original samples, the peak heat release rate (PHRR) and total heat release rate (THR) of DY-PET and FR-PET were significantly reduced. Meanwhile, the limiting oxygen index (LOI) of DY-PET and FR-PET was also improved, indicating the improved flame retardant properties of DY-PET and FR-PET. In addition, the anti-dripping performance was excellent, which was mainly due to the high temperature self-crosslinking, high temperature ionic aggregation and hydrogen bond & π-π stacking effect. The improved flame retardant performance of FR-PET was attributed to the blocking effect of the generated char layer catalyzed by APSFA under high temperature and the dilution effect of incombustible gas resulting from the thermal decomposition of APSFA. This work provided a scalable strategy for the design of dyeing, flame retardant and anti-dripping PET fibers, and endowed PET with great potential application in the field of functional polymer materials.