Chemiluminescence from oxidation of polypropylene: Some comments on a kinetic approach

We present a detailed criticism of the kinetic approach to the analysis of data obtained from measurements of the very weak chemiluminescence accompanying the oxidation of polypropylene. It is shown that a kinetic model proposed by other workers is based upon invalid assumptions, leads to kinetic parameters which are not sensible, and requires measurement of the properties which it claims to predict

Physical spreading and heterogeneity in oxidation of polypropylene

The oxidation of solid polypropylene measured by chemiluminescence (CL) has been interpreted as involving heterogeneous initiation that leads to high oxidation rates in localized zones and is followed by the physical spreading of oxidation. Evidence of the high activity of oxidizing centers to promote further oxidation of even physically separated PP powder particles has been obtained. In such a model of highly reactive centers existing from the earliest onset of oxidation, an induction period was related to the physical characteristics of the material rather than the chemical interpretation in liquid-state kinetic models. Therefore, failure of the material may be related to the spreading of a few centers of initial oxidation of the polymer. quotcopy; 1996 American Chemical Society

Oxyluminescence study of the degradation of filled and unfilled rubbers

SIGLEAvailable from British Library Lending Division - LD:2265.63F(BR--94542) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Photolysis and photooxidation in engineering plastics

The most important UV-degradation mechanisms for polymers are photolysis and photo-oxidation. For polyolefins it is well known that photo-oxidation is the dominating mechanism. These polymers do not have an inherent absorption at wavelengths present in terrestrial sunlight (>290 nm) so photolysis cannot play an important role. In contrast to polyolefins, the majority of engineering plastics do have absorptions at these wavelengths. As a result, for these polymers, besides photo-oxidation, photolysis can play an important role. For polyamide 6, poly(butylene terephthalate), two different copolyetheresters and bisphenol-A polycarbonate, the importance of photolysis as well as that of photo-oxidation in polymer light-induced degradation is discussed