Relationship between surface rearrangement and adhesion strength of poly(ethylene-co-acrylic acid) LDPE blends to aluminum

The adhesion strength between poly(ethylene-co-acrylic acid) (PEAA) and aluminum (Al) was investigated by varying the acrylic acid content in PEAA and the zero shear viscosity of PEAA. In PEAA and low-density polyethylene (LDPE) blends/Al joints, the effects of PEAA on the adhesion strength between PEAA/LDPE blends and Al were also studied by varying the acrylic acid content in PEAA and the amount of PEAA in PEAA/LDPE blends. A 90 degrees peel test was employed to measure the adhesion strength. In order to examine the interface concentration of acrylic acid in PEAA/Al joints and PEAA-LDPE blends/Al joints, the contact angles of n-octane and air on PEAA and PEAA/LDPE blends were measured under water as a polar medium instead of on Al. The locus of failure changed from cohesive failure in the polymer film to adhesional failure with increasing PEAA content in the PEAA-LDPE blends as judged by the unaided eye and X-ray photoelectron spectroscopy (XPS).