Infrared and thermogravimetric studies of the thermal degradation of chrysotile asbestos fibers: evidence for matrix effects

Thermal decomposition of short chrysotile asbestos fibers under static heating has been studied by infrared spectroscopy and thermogravimetry. The spectral changes were monitored at room temperature for fibers heated (a) in the free state or (b) in KBr matrix. In either case dehydration occurs sharply near 550 °C. However, subsequent transformations of the chrysotile anhydride were found to be markedly different for (a) and (b), suggesting important matrix effects. This provides an explanation for earlier observations in which the thermal decomposition scheme appeared dependent of the size of the chrysotile fibers.