Influence of phosphomolybdic acid-based ionic liquid and layered double hydroxide on the properties of intumescent flame-retardant thermoplastic polyurethane elastomer composites

The phosphomolybdic acid-based ionic liquid (PMAIL) was synthesized by ion-exchange method, and it was compounded to the intumescent flame-retardant thermoplastic polyurethane elastomer (IFR/TPU) compo-sites together with layered double hydroxide (LDH). The effect of PMAIL and LDH on the flame retardant properties, thermal stability and processing fluidity of IFR/TPU composites was investigated. The results show that the combination of PMAIL and LDH improve the flame retardancy and thermal stability of IFR/TPU composites. When the mass ratio of PMAIL, LDH and IFR is 0.2∶1.0∶8.8 and the total addition amount is 10wt%, the limiting oxygen index of the PMAIL-LDH-IFR/TPU composites is increased to 30.1% and the vertical burning test reach UL-94 V-0 rating. Moreover, the peak heat release rate and total heat release of PMAIL-LDH-IFR/TPU sample are reduced by 88.06% and 45.88% respectively compared with that of control TPU. The changes in the results such as the balanced torque, melt index and melting temperature indicate the improvement of processing fluidity for PMAIL-LDH-IFR/TPU composites.