8 июля, 2015 
Malyar DACCO SCI, Inc., Columbia, Maryland, U. S.A.
Although obtaining high initial bond strength is relatively easy, maintaining good bond durability in aggressive environments is comparatively more difficult. The most important factor leading to bond degradation of most materials is moisture. Moisture is pervasive over much of the world and is responsible for the vast majority of bond failures, both in the field during service and in the laboratory during research and development.
The importance of adhesive bond durability will vary depending on the particular application and environment. One of the most critical cases is military and civilian aircraft, especially those that operate in tropical, coastal, or marine locations. At the other extreme, less critical applications include those subject to low stresses and protected from harsh environments, such as interior furniture in temperate climates [1] or even wrapped gift packages. Increased durability generally requires additional initial cost through more expensive materials or processing. Consequently, it makes little sense for a bond to have a significantly longer lifetime than the item or system of which it is a part. In this chapter, we will concentrate on applications where durability is a critical issue, such as the aerospace industry—an emphasis natural to the topic.
The rate of bond degradation depends on a number of variables that can be grouped into three categories: environment, material, and stress. The environment is dominated by temperature and moisture. It can also include the concentration of aggressive ions, such as chlorides, and the presence of fuels, deicers, and other fluids. Electrochemical potential, either directly applied or created by galvanic couples, and extreme pH can also promote degradation. The material grouping is all-inclusive and includes the adherend, the adhesive, and the interphase between them. Finally, the stresses to which the bond is subject either during or after exposure also influence its lifetime or residual strength.
Each of these factors will be discussed in more detail. We also review the means to enhance durability. Entire books can and have been written on durability; in this short chapter, we can only touch on the subject. For more details, the reader is referred to the many reviews in the literature [1-13].
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