Durability of a reference material over diverse conditions

摘要

A polyethylene film with phenolic antioxidant and phosphite synergist, has been proposed to be a standard reference material for the oxidative induction time measurement by DSC (differential scanning calorimetry) [R.L. Blains, A proposed reference material for oxidative induction time by differential scanning calorimetry, in: A.T. Riga, G.H. Patterson (Eds.), ASTM Special Technical Publications, STP 1326, ASTM, W. Conshohocken, PA, 1997, pp. 193-204.], ASTM D-3895 [ASTM D-3895-92, Test Method for Oxidative Induction Time of Polyolefins by Differential Scanning Calorimetry]. We have examined the oxidative stability of this material over diverse conditions. These include oxidative induction time in air, over broad temperatures; induction time in pressurized oxygen in a pressure DSC, circulating oven. and samples subjected to different doses of ionizing radiation. It appears that when the lifetime is presented in the Arrhenius form, a progressively diminishing activation energies toward room temperature was observed. After combining experimental OIT (oxidative induction time) data of up to about 8 years, a conservative estimate of durability of about 30 years was obtained. (C) 2000 Published by Elsevier Science B.V. [References: 6]