Thermal Transition Behavior, Thermal Stability, and Flame Retardancy of Low-Melting-Temperature Copolyester: Comonomer Effect

Phosphorus-containing poly­(ethylene terephthalate-<i>co</i>-diethylene terephthalate) (PEDT) with a low melting temperature was synthesized through esterification and copolycondensation of terephthalic acid, ethylene glycol, diethylene glycol (DEG), and 3-(hydroxyphenylphosphinyl)­propionic acid (HPPPA). DSC results showed that PEDTs still were crystallizable and that the lowest melting temperature of the PEDTs was reduced to 118.0 °C although the chain regularity was destroyed by the incorporation of comonomers. It was found that the addition of HPPPA can improve the thermal oxidative stability of copolyesters. The results of the limiting oxygen index (LOI) test, the UL-94 vertical test, and the cone calorimeter test indicated that HPPPA endowed PEDT with good flame-retardant properties. The LOI values of the PEDTs were increased to 30.5–34.8, the UL-94 ratings of vertical burning were improved to V-0, and both the peak heat release rate (pHRR) and the total heat release (THR) obviously decreased

A Sandcastle-Worm-Inspired Strategy toward Antimicrobial Fouling and Fireproof Composite

Marine composites with antimicrobial fouling and fireproofing are indispensable for ocean facilities that resist extremely harsh environments. Marine life has excited various inspirations to withstand harsh environments, in which sandcastle worms secrete unique adhesives for gluing sand and shell fragments together to build robust and protective habitats. Herein, we design an adherable macromolecule interface containing tyramine and ammonium phosphate motifs to create superhighly flame-retardant and excellent antibacterial functional composites. The results demonstrate that the phenolic hydroxyl groups in tyramine improve the chemical affinity among ammonium polyphosphate, vinyl ester resin, and carbon fibers due to the great adhesion, while also exhibiting excellent broad-spectrum antimicrobial fouling properties for bacteria, mold, and algae. The tyramine and ammonium phosphate groups synergistically achieve superhigh fire-safety performance beyond current levels to powerfully defend human life in maritime confined spaces. This sandcastle-worm-inspired strategy emerges as an attractive candidate for super antimicrobial fouling and fireproof protection in extremely harsh ocean environments