AN EXPERIMENTAL-TECHNIQUE TO MEASURE THE ADHESIVE STRENGTH BETWEEN INCLUSIONS AND TRANSPARENT MATRICES

An experimental method is presented to measure the adhesive strength b etween spherical inclusions and transparent host matrices, The techniq ue was developed to measure reliably the adhesive strengths between pa rticles and resin matrices. Commonly used adhesion tests possess ill-d efined stress concentrations inherent in their design that make them u nsuitable for the determination of true adhesive strengths. The proced ure developed here involves embedding a sphere of the candidate partic le material in the contoured neck portion of a cylindrical epoxy bar ( or that of other transparent resin). The decohesion of the sample from the epoxy is observed as the bar is strained in tension. The radial s tress at the poles leading to decohesion is then determined by means o f a numerical solution of the deformation problem. Adhesive strength d ata were obtained from a number of epoxy specimens containing particle s of Delrin, Nylon, polycarbonate and silica glass, and are presented here and discussed in relation to particle-surface pre-treatments.