STABILIZATION OF LINEAR POLYETHYLENE CROSS-LINKED BY IRRADIATION

Our experiments have shown that after a complex degradative effect, such as processing, irradiation and ageing, the effects of antioxidants and their mixtures are very different. The results of our investigation support the opinion, expressed by many researchers of stabilization, that there does not exist any universally practicable antioxidative system. The optimal effect has to be determined, for each system, in the knowledge of the quality and quantity of the given oxidative load. For polyethylene crosslinked by irradiation a satisfactory stability can be attained with the aid of the usual stabilizers; however, they must be used in relatively larger quantities owing to the additional degradative action of the irradiation. There are noticeable differences between the stabilizers not only in their stabilizing action, but also in influencing the degree of discoloration and in the dose number required to produce the same degree of crosslinking. © 1990 Hüthig & Wepf Verlag, Basel