Chemiluminescence study on the oxidation of several polyolefins - I. Thermal-induced degradation of additive-free polyolefins

Chemiluminescence (CL) has been applied to evaluate the oxidation susceptibility of various polyolefins: low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE) and isotactic polypropylene (i-PP). The intensity of CL emission in inert atmosphere could be related to the previous oxidation level. The thermal stability at 170 degrees C of the hydroperoxides in LDPE seems to be lower than that in LLDPE or HDPE. The kinetic parameters of the oxidation at 170 degrees C in oxygen, calculated from CL data, suggest the following stability order: HDPE > LLDPE > LDPE>>i-PP. The intensity of CL emission was related to the CH3 content as evaluated by Fourier transform infra-red spectroscopy. (C) 1998 Elsevier Science Limited. All rights reserved.