Cyclotriphosphazene fibre reinforced poly(benzoxazine-co-ε-caprolactam) nanocomposites for flame retardant applications

Cyclophosphazene nanotube (PZT) incorporated poly(benzoxazine-co-E >-caprolactam) (P(BZ-co-CPL)) nanocomposites were developed for improving flame retardant properties. The effects of PZT on the flammability properties of P(BZ-co-CPL) matrix were evaluated through UL-94 flammability test and limiting oxygen index (LOI). The UL-94 results of P(BZ-co-CPL)/PZT hybrid nanocomposites showed V-1 rating, whereas neat P(BZ-co-CPL) showed burning rating. The LOI values are increased from 25.4 to 31.4 for 1.5 wt% PZT incorporated P(BZ-co-CPL) nanocomposite systems. SEM was used to study the char morphology of P(BZ-co-CPL)/PZT after being exposed to UL-94 flammability test. Data from thermal studies indicate that the PZT incorporated P(BZ-co-CPL) systems possess better T (g) and thermal degradation behavior when compared to the neat P(BZ-co-CPL). The values of dielectric constant are decreased with increasing temperature. From the values, it is ascertained that the P(BZ-co-CPL)/PZT systems exhibit stable dielectric behavior with regard to variation in temperature. The TEM images ascertain the uniform dispersion of PZT in the P(BZ-co-CPL) matrix.