The effect of metals on thermal degradation of polyethylenes

A chemiluminescence study on thermal degradation of some polyethylenes (LDPE, LLDPE, HDPE, UHMWPE) on seven metal trays in the presence of triazines as stabilisers was carried out. The kinetic effects of metals (Al, Zn, Ti, Mo, Mn, Fe and Cu) were assessed at 200 degreesC by the calculation of oxidation induction period, half-oxidation time, maximum oxidation time and rate in the propagation stage. Different sequences of catalytic effect provided by the studied metals in LDPE and HDPE are reported. A characteristic copper index for each metal was also calculated. Some considerations on the thermal stability of polyethylenes in intimate contact with metal surfaces are presented. (C) 2003 Elsevier Ltd. All rights reserved.