Fabrication of fullerene-decorated graphene oxide and its influence on flame retardancy of high density polyethylene

Fullerene (C60) decorated graphene oxide (GO), denoted as GO-d-C60, was synthesized through a three-step chemical process, including acylating chlorination of GO, amino-functionalization of GO and addition reaction of C60 molecules with amino groups, with the purpose of promoting the dispersion of GO in high density polyethylene (HDPE) and further improving thermal stability and flame retardancy of HDPE/GO composite. Infrared spectroscopy (IR), transmission electron micrographs (TEM) and X-ray photoelectron spectroscopy (XPS) proved that about 2.3 wt.% of C60 molecules, with the size of about 40–70 nm, were bonded onto the surface of GO and mainly located on the edge of GO sheets. The chemical decoration made GO-d-C60 to have better dispersion in HDPE than GO, favoring the formation of compact and integrated char barriers when heated or ignited. Consequently, GO-d-C60 improved the thermal stability and flame retardancy of HDPE more effectively than pristine GO, due to the assembly of the barrier effect of GO and the radical-trapping effect of C60.