Design and Synthesis of PET‐Based Copolyesters with Flame‐Retardant and Antidripping Performance

Poly(ethylene terephthalate) (PET) is a fiber-forming polymer with the largest output and widest usage. Its flame retardation is well-achieved via a mechanism of promoting the melt dripping while ignited. However, the melt dripping leads to secondary damage and an immediate empyrosis during fire. How to address the contradiction between the flame retardation and the melt-dripping behavior of PET via an inherent flame-retardant approach becomes a real challenge. This feature article highlights the design and synthesis of novel PET-based copolyesters with flame-retardant and antidripping performance. Three approaches are used to design these copolyesters: "ionic aggregation," "smart self-cross-linking," and "rearrangement at high temperatures." Some new conceptions are proposed accordingly. The synthesis, structure characterization, and properties of those copolyesters are discussed together with the ongoing challenges and limitations at this frontier.