No abstract

In this study, an effect of iron oxide (Fe 2 O 3 ) impurity in talc on degradation behavior of polypropylene (PP)/talc composite was studied using a PP/Fe 2 O 3 model composite sample. The thermal oxidative degradation was performed at 100 C. Although the degradation of a pure PP sample hardly occurred at such temperature, the existence of Fe 2 O 3 induced the PP degradation. The degraded PP part was formed around the Fe 2 O 3 grain in the PP/Fe 2 O 3 sample. It was found from the optical microscope observation that the degraded PP was able to diffuse only within the PP amorphous part. The analysis of the oxidation distribution on the degraded PP surface was performed employing a scanning electron microscope/electron dispersive spectrometer. The result showed that the PP spots in the vicinity of the Fe 2 O 3 grain were unoxidized during the initial degradation process, and the oxidized PP spots were located at around 6 lm distance from the Fe 2 O 3 grain. It was concluded that the degradation was initiated microscopically away from the Fe 2 O 3 grain so that the Fe 2 O 3 had both the abilities to accelerate the decomposition of PP hydroperoxide compounds and to reduce the produced radical species into nonradical products.