The Synergic Effect of Primary and Secondary Flame Retardants on the Improvement in the Flame Retardant and Mechanical Properties of Thermoplastic Polyurethane Nanocomposites

Abstract

Recently, nanocomposites of polymers have attracted attention due to their advanced features compared to their complement polymer microcomposites. In this study, thermoplastic polyurethane (TPU) was used as a matrix; antimony trioxide (primary flame retardant) and montmorillonite organo-clay (secondary flame retardant), along with benzoflex (plasticizer), were used as fillers to examine their synergistic effect. Nanocomposites of various compositions (TPU-1 to TPU-6) were prepared via the melt-mixing method and compressed to form sheets of the desired dimensions with a compression molding hydraulic press machine. Characterization of the samples was conducted with Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). A tensile test was performed through a universal testing machine (UTM) which showed that the Young’s Modulus improved from 147.348 MPa for the pure sample (TPU-1) to 244.568 MPa for TPU-6. A UL-94 test was executed to observe flame retardance. The sample of interest (TPU-6) achieved V-0 classification in UL-94. All these results confirmed the synergistic effect of primary and secondary flame retardants. An optimum increase in fire resistance and mechanical strength was observed for TPU-6.