ABSTRACT
Support for this has been given by recent FTIR emission studies of single particles of polypropylene (91) in which higher oxidation products, such as y-Iactones, were formed at the earliest stages of oxidation. This was consistent with the involvement of primary and secondary alkylperoxy radicals in the CL-producing reaction, and the sequence of reactions leading to CL from polypropylene clearly differ significantly from those in polyethylene. The Russell mechanism also requires that oxygen is produced in an excited singlet state, and there is evidence that the decomposition of polypropylene hydroperoxide produces singlet oxygen (92).
Although CL may be observed in both the liquid and solid states, the kinetic methodology generally applied has been one of a homogeneous free radical chain reaction. The intensity of CL, I, is given by the application of the steady-state approximation to the reaction sequence, shown in Eqs. (1')-(6') of Section II.C, so that
