Accelerated aging, methods for

Aging of spirits involves oxidation. It is this reaction which one attempts to hasten by the processes devised for accelerated aging. Methods for aging spirits artificially fall into four main classes as follows (1) treatment with air, oxygen, or ozone (2) exposure to actinic rays (3) electrolytic treatment and (4) use of catalysts. Combinations of these methods are likewise employed. 

The time accelerated aging method for electric wires and cables requires a high dose rate irradiation, but the exposure to polymer in air results only the oxidation of surface when the dose rate is higher. I previously reported the methodology study of time accelerated irradiation of elastomer (2). The study showed two appropriate methods, one was irradiation in pressurized oxygen at room temperature the other was irradiation at 70°C in air. The article studied the effect of higher dose (up to 10 MGy) irradiation on ethylene-propylene-diene elastomer (EPDM) by using the time accelerated method. Irradiation at 70°C in air was chosen as the time accelerated irradiation condition because of the experimental convenience. 

Sun, D.C. 1996. Simple accelerated aging method for long-term post-radiation effects in UHMWPE implants. In Fifth world biomaterials congress. Toronto Society for Biomaterials. 

Sun, D.C., Stark, C., Dumbleton, J. H. Development of an Accelerated Aging Method For Evaluation of Long-term Irradiation Effects on UHMWPE Implants, Irradiation of Polymers, ACS Symposium Series, American Chemical Society, 1996... 

Sun DC, Stark C, Dumbleton JH. Development of an accelerated aging method for evaluation of long-term irradiation effects on UHMWPE implants. Polym Repr 1994 35 969-70. 

S.M. Kurtz, O.K. Muratoglu, F. Buchanan, B. Currier, R. Gsell, K. Greer, G. Gualtieri, R. Johnson, S. Schaffner, K. Sevo, S. Spiegelberg, F.W. Shen, S.S. Yau. Interlaboratory reproducibility of standard accelerated aging methods for oxidation of UHMWPE. Biomaterials 22(13), 1731-1737, July (2001). 

The lack of an unambiguous method for demonstrating predictive validity of thermal accelerated-aging methods warrants extreme caution in extrapolating to long-term behavior for polymer-adhesive systems. The usefulness of such studies is often best applied to a ranking of preferred behavior under evaluative criteria. 

Develop time- and geometry-based scaling techniques to relate laboratory tests to the real performance of a structure, and accelerated test methods for simulating long-term ageing. 

Accelerated aging methods have been developed for evaluating the integrity of medical packaging (ASTM F 1980-02 2002). Nevertheless, because... 

Notice that these principles do not explicitly define the test parameters. However, the guidance documents developed by CDHR do provide accelerated aging protocols for specific devices within their jurisdiction based on the Q,q theory for chemical reactions. So, the theory postulated by Von t Hof using the Qio value (which states that a rise in temperature of 10°C will double the rate of chemical reaction) is the most convenient method of estimating the approximate ambient storage time equivalent at a selected accelerated aging temperature, despite flie Imown limitations and concerns for use on complex and dissimilar material structures. 

A second route is called the accelerated ageing method. It is based on a lambda measurement after storing the board for 25 weeks at 70 "C, followed by the addition of a safety increment. This safety increment can be reduced, depending on the outcome... 

Maxwell, A.S., Broughton, W.R., Dean, G., Sims, G.D. Review of accelerated ageing methods and lifetime prediction techniques for polymer materials, NPL Report DEPC MPR 016 (2005). 

Accelerated aging methods wherein specihe elastomer properties are measured at a number of elevated temperatures and stresses over different periods of time provide a means for estimating long-term performance. These same methods may be used, in some cases, to estimate the service performance of actual components. This type of methodology also enables an investigator to determine a rate expression that can be useful for predicting the behavior of an elastomer under other conditions of time, temperature, and stress. 

A hot air chamber used for heating or drying raw rubber, for vulcanising rubber products by the dry heat method, or for carrying out accelerated ageing by the air oven method. On the continent of Europe, the term oven is sometimes used in the sense of autoclave. 

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