Abstract
Rolling-bearing cages (separators) which were made by injection moulding from polyamide 66 filled with short glass fibres were tested before and after exposures in hot air at temperatures 120, 140, 160, and 180°C at various times ranging from a few hours to three weeks. The cages were loaded in tension and the changes of maximum force corresponding to ultimate tensile stress were studied. A very simple degradation mechanism containing the main features of the real degradation processes was proposed and its kinetic equations were derived. On the basis of the assumption that the changes of properties during ageing are proportional to the changes of chemical composition and structure a regression function was proposed. It was used for the fitting of the measured results and for the construction of predictive curves which describe the temporal and temperature dependence of strength for working temperatures and long times.
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References
ISO 2578–1974 Plastics, Determination of time-temperature limits after exposure to prolonged action of heat.
DIN 53 446 Testing plastics, Determination of time-temperature limits (in German).
M. I. Cohan (ed.), "Nylon Plastics" (John Wiley & Sons, New York, 1973) p. 375.
H. Reymers, Mod. Plast. 47 (1970) 78.
?CSN 64 0768 Testing Plastics, Determination of time-temperature limits (in Czech).
?CSN 64 0007 Plastics, Statistical methods for evaluation of long-time test results of mechanical properties (in Czech).
GOST 9.707–81 Unified system of corrosion and ageing protection, Polymeric materials. Methods of accelerated climatic ageing tests (in Russian).
J. Kohout, in Proceedings of International Conference on Advanced materials and Technologies, Plze?n, June 1995, editor not mentioned (?SKODA-Research Plze?n & Technical University of Brno, Plze?n and Brno, 1996) Vol. 2, p. 24. Czech translation in Jemn´a mechanika a optika 41 (1996) 255.
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Kohout, J. Strength changes of moulded polyamide composite caused by thermal oxidation. Journal of Materials Science 34, 843–849 (1999). https://doi.org/10.1023/A:1004593417901
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DOI: https://doi.org/10.1023/A:1004593417901