Polymer durability estimates based on apparent activation energies for thermal oxidative degradation

In order to further our understanding of polymer durability, the degradatio n kinetics of a series of polymers was studied. The Arrhenius activation en ergy was used as the parameter to follow the rate dependence as a function of temperature. For most systems, it was evident that the apparent activati on energies increase monotonically with temperature. This finding explains the frequent observation that kinetic parameters obtained at high temperatu res often lead to grossly optimistic estimates of shelf life at ambient con ditions. The activation energies of polypropylene from the surface embrittl ement processes were also found to have a striking similarity to the therma l processes, with nearly identical activation energies at the same temperat ure. A good understanding of this observation could lead to broader applica tions and further the understanding of polymer degradation. (C) 2001 Publis hed by Elsevier Science B.V.