New methods for flame-retarding PET without melt dripping

• DOI: 10.1360/tb-2020-0911
• Publication Date: 2020-10-19T04:29:06Z
• Authors: Lin Chen; Bowen Liu; Teng Fu; Yanpeng Ni; Xiuli Wang; Yuzhong Wang
• Keywords: 02 engineering and technology; 0210 nano-technology

Polyethylene terephthalate (PET), as the largest synthetic polymer with an annual output of more than 90 million tons, has found widespread applications in our daily life and industry, especially its fiber accounts for about 90% all fibers. However, PET is highly flammable melt-dripping during burning, which causes serious casualties property loss case fire. Although many phosphorus-based flame-retardant PETs are already commercially available, their flame retardancy usually achieved by promoting melt dripping PET. The issue on retardation without was a big challenge both academia not been addressed long time because anti-dripping behavior conflicts “dripping-promotion” mechanism phosphorus-containing Therefore, how to flame-retard become urgent difficult problem needed solve. key designing performance increase viscosity char formation ability burning. Herein, we reviewed original works series copolyesters designed synthesized via chemically incorporated functional monomers into chains based “physical interaction”, “high-temperature chemical self-crosslinking” rearrangement”. Those exhibit high polymerization activity monomers, those special groups do affect or processing process. Once at higher temperature under actions “ionic aggregation”, “hydrogen bond”, “chemical rearrangement”, strength PET-based would be greatly increased, upgrading excellent anti- non-dripping performance. What more, dense cyclic aromatic structures, enabled these groups, can further evolve stable intumescent layers surface copolyesters, inhibit heat oxygen transfer. Thus, good same time. In detail, physical crosslinking networks, formed thermally-reversible ionic aggregation, limit movement molecular some extent, but such effects enough make corresponding achieve vertical burning test (UL-94). Compared crosslinking, irreversible networks stronger. Based this idea, have proposed novel “intelligent containing crosslinkable phenylacetylene, phenylacetylene-phenylimide, phenylmaleimide, schiff base azobenzene groups. rapidly crosslink polymerization/processing form cross-linked resulting properties. addition, aryl ether, bisphenol F o-hydroxy phenylimide also used improve rearrangement reactions charring promotion temperatures. Among above, self-crosslinkable rearrangeable exhibited efficiency, attain standard lower amount third monomers. Without use traditional retardant elements halogen, mechanisms approaches only opened up way carbonization polyester, provided new strategies green development technology. understanding design synthesis deepened breakthroughs recent years, still faced unavoidable challenges reducing monomer contents, decreasing cost, optimizing mechanical properties, improving crystallinity keeping spinnability process practical application industrialization future. Actually, efficient cheaper recently. much content endow comprehensive performances retardance, non-dripping, crystallization, spinnability, dyeability These state-of-art results will presented near