Abstracts of Bell System Technical Papers Not Published in this Journal (01 January 1954)

Telephone-System Applications of Recorded Machine Announcements, A.I.E.E., Trans., Commun. & Electronics 8, pp. 478-483, Sept., 1953. BIELING, D . , see D. EDELSON. BIGGS, B . S . 1 and W . L . HAWKINS 1 Oxidative Aging of Polyethylene, Modern Plastics, 31, pp. 121-122, 1 2 4 + , Sept., 1953 (Monograph 2155). Thermal oxidation of polyethylene follows the pattern set by lower hoinolognes such as paraffinic waxes and oils. It is an autocatalytic free radical chain reaction and is subject to inhibition by typical antioxidants. The rate of degradation in the dark at room temperatures is found to be extremely low. 

Photo-oxidation of polyethylene is rapid in contrast with that of saturated low molecular weight aliphatic hydrocarbons. Furthermore, antioxidants are of little benefit in protecting against exposure to light. Opaque pigments are of great value in reducing the effects of light, finely divided carbon black being particularly effective. By proper compounding polyethylene can be made to last many years outdoors. BOZORTII, BROWN, R. W. M . , see H. J. L.1 WILLIAMS.