AGING OF LDPE-APP BLENDS USING HIGH OXYGEN-PRESSURE

Low density polyethylene-atactic polypropylene (LDPE-aPP) blends were aged under 0.5 MPa of oxygen at 80-degrees-C. The oxidation of these b lends was monitored using transmission infra-red spectroscopy. Changes of the elongation at break and tensile strength at break as a functio n of ageing time and blend compositions were determined from stress-st rain measurements. It is shown that the elongation at break decreases slightly for the aged blends which contain less than 30% of atactic po lypropylene. These data were related to the different sensitivity of p olyethylene and atactic polypropylene to oxidative degradation.