Influence of a monofunctional acid-base environment on peel mechanics

Abstract

There is a strong practical interest in being able to predict the strength of an adhesive bond with a non-destructive technique. The general fracture mechanics (GFM) theory, which assumes a linear relationship between the work of separation and the thermodynamic work of adhesion, allows for the possibility of such a correlation. In this study, a plasticized poly(vinyl butyral) (PVB) and quartz adhesive-adherend system is used to investigate the influence of the work of adhesion on the work of separation in a modified 180° peel test. The work of adhesion may be varied by separately introducing various Lewis acids and bases as functional groups in the adhesive or adherend surfaces, or into the medium in which fracture is carried out. Wetting and surface tension measurements, obtained via the Wilhelmy technique, are used to determine surface energies and acid-base properties. The strong acid functionality of quartz suggests that a basic environment should yield a lower work of adhesion value than an acidic environment. Applying GFM theory allows this prediction to be extended to the work of separation. The measured adhesion strength results obtained agreed qualitatively with this prediction.