Effects of Film Thickness on The Work of Fracture Between Adhesives and Glass

In this investigation, the fracture energy of joints consisting of soda lime glass sandwiched around either an acrylate or poly(vinyl butyral) (PVB) was studied. This was accomplished for various adhesive thicknesses with the use of a tapered double cantilever beam specimen loaded in mode I. For adhesive thicknesses varying between 0.03 mm and 0.80 mm, the fracture energies ranged from 15 to 95 Pam for the glassy acrylate joints and from 375 to 1060 Pam for the more rubbery PVB joints. While the fracture energy was relatively independent of thickness for the acrylate joints, there was an increasing trend in toughness for the PVB joints. The fracture energy of the acrylate joints was modeled with a process zone model with reasonable results while the fracture energy of the PVB joints was modeled with constraints on the plastic zone. Scanning electron microscopy and measured bulk adhesive properties provided necessary input into the models.