Some Practical Aspects of the Oxidative Stability of Polypropylene Pipes

Abstract

The oxidation time and oxidation temperature of a total of 20 specimens with unknown pre-history from various manufacturers of polyethylene and poly(ethylene-co-propylene) are determined. The specimens are in the form of fittings used in piping. The specimens are divided in two groups corresponding to their melting temperature and polyethylene content in the copolymer, respectively. The oxidation activation energy for the two groups is calculated. Reasonable relationship between the measured oxidation time and the time, calculated on the base of the measured oxidative temperature, is obtained. The scattering of experimental data is thoroughly examined and some recommendations aiming at improving the results are suggested. Specific recommendations are given for the cases of technological and post consummative piping waste. The paper critically estimates the accuracy in the measured oxidation time and temperature as well as their mutual relation.