Synergistic Effect of Graphene on Antidripping and Fire Resistance of Intumescent Flame Retardant Poly(butylene succinate) Composites

Intumescent flame retardant poly(butylene succinate) (IFRPBS) composites with enhanced fire resistance were prepared using graphene as synergist. The morphology of fracture surfaces of the composites was investigated by scanning electron microscopy (SEM). The limiting oxygen index (LOT) values increased from 23.0 for the pure PBS to 31.0 for IFRPBS with 20 wt % IFR loading. The addition of graphene further improved the LOI values of the composites and exhibited excellent antidripping properties. The UL-94 VU materials were obtained with a formulation of 18 wt % IFR and 2 wt % graphene. MFI measurement indicated that the presence of graphene significantly enhanced the melt viscosity and restrained the melt dripping. The thermal degradation and gas products of IFRPBS/graphene systems were monitored by thermogravimetric analysis (TGA), real time Fourier transform infrared spectrometry (RTFTIR), and thermogravimetric analysis-Fourier transform infrared spectrometry (TG-FTIR). X-ray photoelectron spectroscopy (XPS) was utilized to explore the chemical components of the outer and inner char residues.