CHEMILUMINESCENCE OF THE THERMO-OXIDATIVE DEGRADATION OF POLYOLEFINS

Chemiluminescence method was applied to evaluate the thermal oxidative stability of various polyolefins, namely high density polyethylene (HDPE), isotactic polypropylene (IPP), polybutene (PB) and poly-4-methylpentene (P4MP). The increasing order of the chemiluminescent intensity of the polyolefins coincided with that of oxygen uptake rate. The thermal oxidative stability of the polymers estimated by both chemiluminescence and oxygen uptake methods decreased in the following order : HDPE>> P4MP> IPP> PB. At an equivalent oxidation level the chemiluminescent intensity of HDPE was much lower than that of three other polymers providing tert-hydrogen in the polymer chains. On the basis of the results obtained the oxidation mechanism of HDPE was discussed.