The Effects of Di-T-Butylperoxide on the Oxidative Stability of Polypropylene Ii

摘要

The oxidative embrittlement of polypropylene film (5 mil) has been studied by measuring stress-strain behavior, molecular weight changes, and development of carbonyl concentration in the infrared spectrum. Oxidation was conducted both in air and in peroxide in the temperature range of 50-90C. The mechanical measurements show the effects of oxidation in the most responsive way; the embrittlement can be clearly seen as a sudden decrease in the elongation at break. The use of infrared carbonyl concentration to follow degradation effects has been found to be ineffective. It is only when the oxidation has proceeded to an advanced stage that the carbonyl concentration begins to show itself at a significant level. The cause of the drastic change in mechanical properties is believed to be the scission of 'tie molecules' in the amorphous phase which interconnects crystallin regions. (Author)