Thermal Degradation Behavior of Styrene-Butadiene-Styrene Tri-Block Copolymer/Multiwalled Carbon Nanotubes Composites

The thermal degradation behavior of styrene-butadiene-styrene triblock copolymer (SBS) and SBS/multiwalled carbon nanotubes (MWCNTs) composites prepared by solution processing and melt mixing, respectively, was investigated using nonisothermal thermogravimetric analysis (TGA). The kinetic parameters of the activation energy (E-a) for degradation, preexponential factor A, and the reaction order (n) were evaluated by the Flynn-Wall-Ozawa, Kissinger, and Coats-Redfern methods, respectively. E-a increased and n decreased after the incorporation of 3 wt% of MWCNTs into the SBS. The E-a of SBS/MWCNTs composite prepared by melt mixing v,,as higher than that by solution processing, which was attributed to the good dispersion of MWCNTs in SBS and the interactions between MWCNTs and SBS. The gases evolved during thermal degradation at a nitrogen atmosphere were studied by Fourier transform infrared spectroscopy (FTIR) coupled with the TGA. Aliphatic and aromatic C-H peaks appeared simultaneously in FTIR spectra, indicating the thermal degradation of SBS proceeds by a random chain scission process. (c) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 524 531, 2009