Acid-base properties and modeling by quantum chemistry of adhesion interactions at the interface of thermoplastic-aluminum systems

Abstract

Thermoplastic-aluminum systems are used in the manufacture of corrosion-resistant lightweight constructions in aerospace and automotive industries. The adhesion strength of such systems is determined by the mechanism of adhesion interaction. In this article, adhesion interactions between the surfaces of polyethylene terephthalate, poly(propylene carbonate), poly(methyl methacrylate), polystyrene, polypropylene and aluminum were studied to identify a correlation between the acid-base properties of the studied surfaces, the mechanism of adhesion interaction and energy characteristics in thermoplastic-aluminum systems using experimental and theoretical approaches. The experimental approach consisted of finding the values of the free surface energy components, the acidity parameters of thermoplastics and aluminum by the E.J. Berger and van Oss-Chaudhuery-Good methods. The theoretical approach consisted of the study of adhesion interactions in thermoplastic-aluminum systems using the quantum chemistry method B3LYP-GD3/6-31G(d,p). It was theoretically established the functional groups to be the active sites on the thermoplastics surface. At the same time, the strongest adhesion interaction is manifested in systems formed by a carbonyl oxygen atom.The experimental values of the components of the free surface energy of thermoplastics and aluminum are in good agreement with the theoretical values of the energy and force of the adhesion interaction of the systems under consideration.