Improving Interfacial Adhesion Between Thermoplastic Polyurethane and Copper Foil Using Amino Carboxylic Acids

A chemical methodology to improve the adhesion between copper foil and a thermoplastic polyurethane (TPU) matrix is reported. The copper foil (0.127 mm thickness) was treated with aminocarboxylic acid-based Coupling agents such as 6-aminohexanoic acid and 4-aminobenzoic acid. 3-Aminopropyl trimethoxysilane was also used as a conventional silane coupling agent for comparative studies. The interfacial adhesion between copper foil and laminated TPU was examined by means of peel adhesion test, scanning electron microscopy, and attenuated total reflection-infrared spectroscopic methods. The treatment of copper foils with 6-aminohexanoic acid resulted in improved adhesion, which was equal to that of the silane-treated system. The mechanism of how the coupling agents strengthen the interfacial adhesion between TPU and copper foil is discussed. The solution concentrations of the coupling agents were optimized with respect to the peel adhesion of the interface. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 1738-1744, 2009