AN OVERVIEW OF THE TECHNOLOGIES FOR ADHESIVE DEBONDING ON COMMAND

Adhesive bonding has found applications in various areas from high technology industries such as aeronautics, aerospace, electron ics, and automotive to traditional industries such as construction, sports and packagi ng. Adhesives can be used to join metals, polymers, ceramics, cork, rubber, and combi nations of any of these materials. The use of adhesive bonding rather than mechanical fasteners offers the potential for reduced weight and cost. However, one of the drawback is its “permanence” character as the joints are not easy t o disassembly. In most of the cases, structural adhesive joints cannot be disasse mbled without destroying the substrates. Nowadays, the widely used new materials (i.e. ceramics, carbon fibre reinforced polymers (CFRP), etc.) are usually expen sive which create an increasing demand for recyclability, driven by economic as wel l as environmental reasons. Thus, the development of new technologies and proce sses for easy recycle and repair of bonded structures are becoming of great i nterest for the industry. If bonds can be broken without damage of the components, rec ycling is easier. Also for an environmental friendly disassembly of bonded struct ures, it is necessary to separate the joint between the bonded components so that the different materials can be reused on a qualitatively high level. As recycling becomes a necessary and global issue, reversible adhesives or debonding on command of the adhesive joints might become a basic requisite for disassembly and recycl ing in the future. This paper provides an overview of the recent developments in the use of debonding technologies and summarizes the different strategie s and approaches to obtain adhesive debonding on command. The use of thermally expandable particles (TEPs), additives and nanoparticles in adhesive debonding a re discussed. The use of thermally reversible Diels-Alder chemistry into epo xy resins and electrically induced debonding of adhesives are also presented.