4.1 Introduction

The testing of adhesives and sealants is a complex subject because there are many parameters that can affect the test result. Interactions of the adhesive and adherend are often obscure. The joint design and type of load strongly influence the final stress distribution. The parameters by which the test is conducted, such as strain rate, temperature, and environmental conditions, also have a strong impact on the test results.

Although complex, testing is an extremely important subject since one cannot reliably predict the strength of the adhesive bond based solely on characteristics of the adhesive, substrate, and the joint design. To determine the strength of the joint, one must resort to testing.

Through testing the many factors that can affect the strength of the joint can be measured. Sometimes it is difficult to separate the variables that control joint strength, but at least through testing, we have a vehicle to provide a quantitative approximation. Standard tests, such as ASTM tests, are very useful for comparing and determining the consistency of materials and processes. They are less valuable in accurately predicting the strength of specific production joints. Usually, prototype tests must be designed for this purpose.

In this chapter, standard test methods for both adhesives and sealants will be described. Similar test methods are often applied to both adhesives and sealants since adhesion is a major factor in both applications. This chapter will review fundamental tests that are used to control the consistency of materials used in these processes. The...