Chemiluminescence spectral evolution along the thermal oxidation of isotactic polypropylene

Abstract

Several isotactic polypropylene samples have been thermally oxidised and their chemiluminescence recorded. The experimental device employed has allowed the simultaneous measurement of the integral and the spectral light emitted by the samples during oxidation. It has been found that the spectrum of chemiluminescence remains unchanged along the auto-acceleration stage of oxidation, while a gradual broadening and shift to longer wavelengths occurs as the kinetic curve approaches its intensity maximum, a shift which continues as long as oxidation does so. The shift to longer wavelengths originates in the disappearing of the low-wavelength emission (around 415nm in isotactic polypropylene) which dominates the spectrum along the auto-acceleration stage, concomitant to a growing of longer wavelength components. Correlated stages exist in the kinetics and in the spectral evolution of the chemiluminescent emission along the thermal oxidation of polypropylene. ©