Study of the change in polarity of polypropylene modified in bulk by polar copolymers

The adhesive properties of the blends of isotactic polypropylene with ethylene-acrylic acid copolymers were investigated. It was found that the surface free energy, polar component of surface free energy, polar fraction and mechanical work of adhesion increased with concentration of EAA copolymers in the iPP blends to a degree exceeding additive function. The proportionality of mechanical work of adhesion of the polymer blends to polar fraction that reflects the strength of adhesive joint was also revealed. This observation permits us to claim that the increase in polarity or hydrophilicity of iPP due to modification in bulk by the use of polar EAA copolymer raises the strength of adhesive joints between iPP and more polar polymers. The relationship between mechanical properties of the studied polymer blends and their composition showed the functional additivity of the mechanical parameters.