Influence of environmental concentrations of ozone on thermo-oxidative degradation of PP

Recently it was postulated that natural variations of ozone concentration c ould have a big influence on the oven stability of polypropylene (PP). To e xamine this hypothesis the influence of low concentrations of ozone (compar able with environmental concentrations) on the thermo-oxidative degradation rate of PP-films was determined. PP-films were aged in a draft air oven wi th and without the addition of a small amount of ozone (maximum concentrati on ozone in the oven was 100-200 mug/m(3)). The decrease of the elongation at break as function of oven ageing time was determined. It is shown that c hanges in the environmental concentrations of ozone have no significant inf luence on the rate of degradation in an oven. (C) 2001 Elsevier Science Ltd . All rights reserved.