Investigations of thermal degradation behavior and fire performance of halogen-free flame retardant poly(1,4-butylene terephthalate) composites

This work aims to develop halogen-free poly(1,4-butylene terephthalate) (PBT) composites with enhanced flame retardancy using ecofriendly flame retardants, aluminum hypophosphite (AHP) and melamine derivatives (melamine polyphosphate and melamine cyanurate). Microscale combustion calorimetry and thermal gravimetric analysis/infrared spectrometry (TG-IR) technique were used to investigate the potential fire hazards of these PBT composites. For the PBT composites with the incorporation of AHP and melamine derivatives, the heat release capacity (HRC) which is an indicator of a material fire hazard was significantly reduced, and the intensities of a variety of combustible or toxic gases detected by TG-IR technique were remarkably decreased. Moreover, a loading of 20 wt % flame retardant mixture fulfilled the PBT composites high limited oxygen index (LOI) and V-0 classification in UL 94 testing. An intumescent flame retarded mechanism was speculated in this work, because numerous bubble-like char residues were found on the surface of the samples containing flame retardant mixture after LOI testing. © 2011 Wiley Periodicals, Inc.