Adhesion of semi-crystalline polymers: shear contribution to fracture energy

A study of the adhesion of two semi-crystalline polymers (EVOH and PEg (grafted polyethylene)) by peel has shown that local fracture energy, G_A, is virtually independent of peel angle. Adopting the Dugdale model for energy expenditure, we obtain an estimate of G_A^D of the order of magnitude of G_A. However, observation of fracture fronts suggests that supplementary energy losses occur after separation, due to shear stresses reorienting the fibrillar craze material. A simple model is proposed to estimate this shear contribution to fracture energy, G_A^S, suggesting the potential importance of shear effects in overall fracture energy. To cite this article: A. Guiu, M.E.R. Shanahan, C. R. Physique 3 (2002) 397–402.