Effect of Modified Carbon Nanotube on the Thermal Behavior, Flame Retardancy and Mechanical Properties of Poly(1,4-butylene terephthalate)/Aluminum Phosphinate Composites

In this work, a carbon nanotube modified by inorganic acids ( m -CNT) was blended with poly(1,4-butylene terephthalate) (PBT) and aluminum phosphinate (AlP) to prepare the flame retarded composites. Morphological observations revealed that both the m -CNT and AlP particles were homogeneously dispersed in PBT matrix. Differential scanning calorimeter analysis showed that the mixture of m -CNT and AlP significantly increased the crystallization temperature of PBT resulting from the nucleation effect of m -CNT and AlP. The improvement of thermal stability and tensile strength/modulus were strongly depended on the uniform dispersion of the mixed particles and the interactions between m -CNT and PBT through hydrogen bonding formation. In comparison with PBT/10AlP, PBT/0.5 m -CNT/9.5AlP passed the Underwriters Laboratories (UL) 94 V-0 classification with the higher limiting oxygen index (37.5%) and the lower peak of heat release rate in cone calorimeter testing. The improved flame retardant performance was attributed to the condensed-phase acted by m -CNT combined with the gas-phase effect of AlP.