Fire-safe thermoplastic polyurethane created by a novel silane-containing phosphate

Phosphate is a kind of effective flame retardant for thermoplastic polyurethane (TPU), but it always results in great damage to mechanical properties. Herein, an organic silane-containing phosphonate (CTA-APTES) was prepared by 3-[Hydroxy (phenyl) phosphoryl]propanoic acid, tyramine and γ-aminopropyl triethoxysilane to simultaneously improve the fire safety and decreasing the mechanical loss of TPU. At the loading of 5.0 wt%, TPU/CTA-APTES5 passed the UL-94 V-0 rating, and its limiting oxygen index was 28.5 %, reaching the non-inflammable grade. While showing remarkable flame-retardant effect on TPU, just as important, the tensile strength and elongation at break of TPU/CTA-APTES5 were 11.34 MPa and 244.5 % respectively, increased by 85 % and 1471 % compared with those of control sample TPU/CEPPA-TA5, remarkably reducing the damage of phosphate to mechanical properties of the substrate. This work provided an efficient strategy to utilize silane-containing phosphate to fabricate high-performance fire-safe TPU.