Facile preparation of phosphorus containing hyperbranched polysiloxane grafted graphene oxide hybrid toward simultaneously enhanced flame retardancy and smoke suppression of thermoplastic polyurethane nanocomposites

In this work, a novel type of phosphorus containing hyperbranched polysiloxane (P-HBPSi) was synthesized by sol–gel method, and then utilized to functionalize graphene oxide ([email protected]). The [email protected] hybrids were mixed with TPU by melt compounding. The SEM observation revealed that the [email protected] dispersed homogeneously in the TPU matrix with good compatibility. The TPU/[email protected] maintained high ductility with elongation at break of 1750.8%. The peak heat release rate and total heat release of TPU/[email protected] were reduced by 63.5% and 20.9%, respectively. In addition, the peak smoke production rate and total smoke production of TPU nanocomposites were also reduced dramatically by 58.3% and 36.4%, respectively. The production of phosphorus free radical scavengers in the gas phase and the barrier effects of GO nanosheets, catalytic charring and the unique Si-O-Si framework of P-HBPSi flame retardant in the condensed phase contributed to the outstanding flame retardancy and toxic gas suppression of TPU/[email protected] nanocomposites.