New heat resistant nanocomposites reinforced silicate nanolayers containing triazine rings based on polyamide: Synthesis, characterization, and flame retardancy study

Abstract

N1,N1′-(6-methoxy-1,3,5-triazine-2,4-diyl)dibenzene-1,4-diamine (MTDA) containing triazine ring structure was synthesized and characterized. A new, montmorillonite (Mt) modified by MTDA (MTDA-Mt), was prepared by ion-exchange of sodium montmorillonite (Na+-Mt) with protonated form of MTDA. It was confirmed by Fourier transform infrared spectroscopy and X-ray powder diffraction (XRD) techniques. The results of XRD indicated that MTDA had intercalated with Na+-Mt. A new polyamide (PA) containing triazine ring was synthesized by direct polycondensation reaction of 4,4′-(6-methoxy-1,3,5-triazine-2,4-diyl)bis(azanediyl)dibenzoic acid and 4,4′-diaminodiphenylether and characterized. PA/MTDA-Mt nanocomposites containing 4 and 8 mass% of MTDA-Mt were prepared via blending of MTDA-Mt with the PA by solution intercalation technique in N-methyl-2-pyrrolidone. The nanostructures and properties of the PA/MTDA-Mt nanocomposites were investigated using different techniques. Transmission electron microscopy and XRD results revealed the good dispersion nano silicate layers in the polymer matrix. Thermal properties and flame retardancy of the resulting PA/MTDA-Mt nanocomposites were investigated by thermal gravimetry analyses and microscale combustion calorimetry techniques. The results showed that the addition of MTDA-Mt enhanced the flame retardancy of PA, reflecting the decrease in heat release rate from 111 W/g for PA to 91 and 77 W g-1 for PA/MTDA-Mt nanocomposites.