Synthesis of metal-containing polyurethane/clay nanocomposites

Abstract

The metal-containing polyurethane/organoclay nanocomposites with varying contents of organoclay were prepared via solution intercalation. The organoclay employed was bentonite, whose surface was modified by oleylmethylbis(2-hydroxyethyl)ammonium chloride (OMH). Metal-containing polyurethane has been synthesized by the reaction between hexadenlate Schiff base zinc complexes and isocyanate-terminated prepolymers. The study results of nanocomposites showed that the metal-containing polyurethane intercalated into the layers of organoclay, which was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The structure of metal-containing polyurethanes in the nanocomposites was not changed by the presence of the organoclay silicate layers as evidenced by Fourier transform infrared spectroscopy (FTIR). Thermal stability and flammability of the nanocomposite were studies by thermogravimetric analysis (TGA) and measuring limiting oxygen index (LOI) values, respectively. TGA results indicated that the thermal stability of nanocomposites was not superior to that of the pure polymer a low temperature, however, the nanocomposites had better thermal stability than the pure polymer at high temperature. The nanocomposites were found to be more flame retardant than the pure metal-containing polyurethanes. The experimental results indicated that there is interaction between metal-containing polyurethane chain and surface of organoclay because both of them contain polar species. The organoclay loading was found to have influence on thermal property of the nanocompolsites.