Fire and mechanical performance of nanoclay reinforced glass-fiber/PBT composites containing aluminum hypophosphite particles

The objective of this work is to develop environmentally friendly fire retardant glass-fiber reinforced poly(1,4-butylene terephthalate) (GRPBT) composites with enhanced fire retarded performance using nanoclay and aluminum hypophosphite (AHP). Exfoliated clay nanocomposites of flame retarded GRPBT were fabricated through melt blending process. For the GRPBT/clay nanocomposite in combination with AHP, the heat release capacity which is an indicator of a material fire hazard reduced by 51%. Moreover, significant improvements were obtained in limiting oxygen index along with maintained Underwriters Laboratories 94 ratings. The flame retardancy mechanism of GRPBT/AHP/clay composite was investigated through thermogravimetric analysis and residue characterization. The results indicated that the well dispersed layered silicates in polymer matrix play an important role of “microreactor” during the combustion. In addition, the substitution of a certain fraction of AHP by nanoclay could recover the interface between glass fiber and polymer matrix leading to the improvement of tensile strength.