Combined Effects of Stress, Moisture, and Temperature

The interaction of temperature and moisture causes greater degradation than can be attributed to either environment by itself. There is evidence to suggest that exposure to humid 

Mechanical stress accelerates the effect of environment on the adhesive joint. A great amount of data is not available on this phenomenon for specific adhesive systems because of the time and expense associated with stress-aging tests. However, it is known that moisture, as an environmental burden, markedly decreases the ability of an adhesive to bear prolonged stress, especially at slightly elevated temperatures. 

FIGURE 15.16 Time to failure versus stress for two adhesives in a warm, high-humidity environment, (a) One part, heat cured modified epoxy adhesive. (b) Flexibilized amine cured epoxy adhesive.43 

TABLE 15.17 Comparison of Long-Term and Accelerated Exposures44 

Adhesive type Stress No stress Stress No stress Stress No stress 

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