A Flame Retardant Rigid Polyurethane Foam System Including Functionalized Graphene Oxide

A functionalized graphene oxide (fGO) was prepared by graphene oxide (GO), boric acid and 3-aminopropyltriethoxysilane in an ethanol aqueous solution using ultrasonic agitation. Its structure was characterized by the Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG), and elemental analysis. Subsequently, the fGO was incorporated into the flame-retardant-polyurethane (FRPU) system, in which fGO as a synergist and reinforcing agent, expandable graphite (EG), and dimethyl methylphosphonate (DMMP) as flame retardants, to improve its the flame-retardancy and mechanical properties, evidenced by the limiting oxygen index (LOI), vertical burning test (UL-94) test and the cone calorimeter test (CONE). The LOI value of FRPU/fGO composites reached 28.1% by addition of 0.25 phr fGO and 10 phr EG/DMMP, and its UL-94 test reached V-0 rating. The CONE results revealed that fGO could significantly enhance flame retardant properties of FRPU composites, and the peak heat release rate (PHRR) values value of FRPU/fGO remarkably reduced by 32.9%. Moreover, fGO indeed enhanced the mechanical properties of rigid polyurethane foam (RPUF). (C) 2018 Society of Plastics Engineers