Possibilities of strength prediction of adhesive joints of polymers by master curve method

In the present work it is shown that the strength, depending on temperature and strain, and durability, depending on temperature and static load, of adhesive joints of polymers with adhesive of elastomer type can be predicted from master curves, drawn according to the principle of temperature–time analogy. Shift factors, determined by the Williams-Landel-Ferry (WLF) equation with universal values of constants, have been used to draw the master curves. It allowed to find relations between reference temperature and glass transition temperature of the adhesive. Their existence can be explained on the basis of free volume theory. Referring to the analogous influence of temperature and the part of the plasticizer inserted into the adhesive, on the strength of adhesive joints the existence of temperature–concentration analogy has been determined on the phenomenological level. Nomograms have been suggested for the calculation of strength and durability values from the master curves. Their application is convenient for repeated usage of master curves.