Use of high-performance fibres and intumescents as char promoters in glass-reinforced polyester composites

This work reports the development of novel glass fibre-reinforced composite materials containing a commercially available polyester resin, a phosphate-based intumescent and inherently flame retardant polybenzimidazole (PBI, Celanese), cellulosic (Visil, Sateri), phenol-formaldehyde (Kynol) and oxidised acrylic (Panox) fibres. The intumescent and flame retardant fibre components are added as additives in pulverised form to the resin component of the composite laminate. Thermal stability, char formation and flammability properties of these novel structures are studied by cone calorimetry. The results are discussed in terms of the effect that these char-forming fibres have on promoting further char formation and hence, altering the burning behaviour of resin-intumescent composites.