Electrical and flame-retardant properties of carbon nanotube/poly(ethylene terephthalate) composites containing bisphenol A bis(diphenyl phosphate)

The uniform dispersion of carbon nanotubes (CNTs) in poly(ethylene terephthalate) (PET) was achieved by the liquid bisphenol A bis(diphenyl phosphate) (BDP) assisted pre-dispersion melt mixing. Most of the CNTs existed in a filamentous stretched state and a percolation threshold was achieved at 0.28 vol.% CNTs. In addition, the uniformly dispersed CNTs, acting as a framework to support the char produced by the oxidation of the PET and BDP, inhibited the vigorous bubbling process during combustion. The char adhering to the CNTs lowered their heat-transfer efficiency and made the CNT network layer more compact. Thus, the flame-retardant property was significantly improved since the network layer consisted of CNTs and chars, acting as a heat shield, more effectively reduced the exposure of the PET resin to the external air and heat feedback of the heat flux.