Thermal Degradation Kinetics of iPS/Pd Nanocomposite Prepared by a Drying Process

Abstract

Palladium (Pd) nanoparticles were incorporated into an isotactic polystyrene (iPS) by a one-step drying process through simultaneous vaporization, absorption and reduction processes of palladium(II) bis(acetylacetonate), Pd(acac)2 at 180oC for 30 min. Pd nanoparticles were observed by a transmission electron microscope (TEM), and it was found that metallic nanoparticles were selectively loaded on the amorphous region between the lamellae of iPS. The effect of Pd nanoparticles on the thermal degradation kinetics of iPS was studied by Flynn & Wall equation using thermogravimetric analyzer (TGA) data at various heating rates. The activation energy of neat iPS was ca. 130~204 kJ/mol over the thermal degradation fraction of 0.05~0.40 while that of iPS/Pd nanocomposite was ca. 221~234 kJ/mol over the same range. These meant Pd nanoparticles have positive effect on the thermal degradation of alkyl polymer chains in iPS.