Synthesis and characterization of polyurethane based UV responsive detachable adhesives containing 1,8 cineole as UV Trigger

• Development and characterization of UV-stimulated reusable adhesives. • Sustainable utilization of biobased materials in adhesive synthesis. • Investigation of mechanical performance versus reusability through repeated bonding-debonding cycles. Traditional permanent adhesives restrict component repair, recycling, and sustainability due to their irreversible bonding and poor reworkability. Addressing these challenges requires designing smart adhesive systems with controlled detachment triggered by external stimuli such as light. This study investigated whether eucalyptus oil–derived adhesives can achieve UV-triggered reversible bonding with reliable mechanical performance, enabling recyclable and reusable adhesive systems without conventional PI (photo-initiators). Three formulations were synthesized using plant-based monomers and evaluated via the single lap joint (SLJ) test under 365 nm UV light (33 mW cm –2 ). Mechanical durability, load-bearing capacity, and detachment kinetics were assessed across multiple bonding–debonding cycles. FTIR spectroscopy was used to monitor molecular changes and confirm the UV-responsive detachment mechanism. Formulation S3 achieved seven repeatable UV-triggered debonding cycles, with detachment times increasing from 35 s to 310 s across cycles. It maintained adhesion under a 200 g load for two hours, outperforming S1 (42 min) and S2 (18 min). FTIR confirmed 1,8-cineole–DMG linkages as the light-cleavable sites enabling efficient bond release. This research presents a photo-initiator-free, bio-based adhesive design offering controllable, UV-responsive debonding and recyclability, representing a sustainable alternative to conventional permanent adhesives for industrial and consumer applications.