The purpose of this article is to study how processing parameters can promote adhesion in grafted polypropylene/aluminum laminates made by extrusion coating. The density of bonds created at the interface is quantified by Xray spectroscopy after dissolution of the polymer film. dynamic mechanical analysis (DMA) and tensile tests are performed to characterize the mechanical properties of polymer films. They are linked with the crystalline structure, as revealed by optical microscopy and X-ray diffraction. A numerical model of extrusion coating is used to quantify the impact of cooling conditions on adhesion. A good correlation is found between the temperature history, the formation of bonds, and the mechanical properties of the polymer films. High temperature conditions can improve adhesion by increasing the open time for the reaction and the rate of the chemical reaction between grafted polymer chains and aluminum. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 2609-2624, 2009