Acetal-functionalized polyurethane adhesives: A path to debonding-on-demand
Tankut Türel, Patrick Schara, Anna Cristadoro, Martin Linnenbrink, Željko Tomović
Abstract
• Acetal decorated polyurethane adhesives were applied to various substrate combinations. • Adhesives remained stable in neutral conditions but debonded under mild acidic triggers. • Acid-triggered debonding enabled adhesive-free substrate recovery for recycling. • Lap-shear strength surpassed that of conventional PPG-derived reference adhesive. Polyurethanes stand out as remarkably versatile polymers, renowned for their adjustable mechanical and thermal characteristics, making them invaluable across various domains, notably in adhesive applications. Yet conventional polyurethane adhesives typically form permanent bonds, and thus debonding is not possible without harming the bonded substrates. In the light of escalating calls for sustainability, the development of polyurethane adhesives with debonding-on-demand capabilities has become paramount. Such innovations facilitate disassembly, repair, exchange, and recycling of bonded materials. Consequently, herein, we integrate three different linear acetal polyols into one-component, polyether-based polyurethane adhesives. These new systems not only exhibit comparable thermal properties and superior adhesive performance to conventional adhesives but also offer debonding-on-demand capabilities. These findings provide a drop-in solution to the limitations of traditional bonding methods and foster a circular economy, underscoring the pivotal role of adhesive technology in addressing environmental imperatives.