Thermochimica Acta, Vol.472, No.1-2, 31-37, 2008
A study of the thermo-mechanical behavior of Boehmite-polyamide-6 nanocomposites
Some of the important thermo-mechanical characteristics of Boehmite-polyamide-6 nanocomposites are presented. Two different types of Boehmite (gamma-AlOOH) are investigated, which are unmodified and surface-modified using a titanate-coupling agent. Since use-temperature range is one of the most important parameters for engineering polymers, heat distortion temperature (HDT) and glass transition temperature (T-g) of the nanocomposites are analyzed in detail. According to the dynamic mechanical analysis (DMA), both storage and loss modulus show a gradual increase with (Ti-)Boehmite concentration. Compared to the HDT of the unfilled polymer (67 degrees C), there is a tremendous increase in HDTs of the nanocomposites up to 143 and 155 degrees C at 9% Boehmite and 15% Ti-Boehmite contents, respectively. PA6-Boehmite samples show a random variation in T-g values whereas the PA6-Ti-Boehmite samples have a certain trend: T-g values gradually decrease in the beginning, and then increase with filler concentration. It is shown that both series of nanocomposites have similar thermo-oxidative stabilities. Therefore, both the trend in T(g)s and the lower HDT values at low Ti-Boehmite contents are attributed to the plasticizing effect of the titanate-coupling agent. Complex Halpin-Tsai model has been used to assess the temperature-dependent mechanical properties of the nanocomposites. (C) 2008 Elsevier B.V. All rights reserved.
Keywords:nanocomposite;Boehmite;heat distortion temperature;glass transition temperature;thermo-oxidative stability