Cross-linked Polyperoxides for Photoremovable Adhesives

Photoremovability of cross-linked polyperoxides was investigated considering the application to dismantlable adhesives. Applying lap-shear stress on the glass joints bonded by the cross-linked polyperoxides, i.e., the alternating copolymer of 2-hydroxyethyl sorbate and oxygen cross-linked by tolylene 2,4-diisocyanate, resulted in the failure of the glass adherend. UV irradiation on the bonded glass joints more than 19 J/cm(2) resulted in a significant decrease in the lap-shear adhesion strength due to the photodegradation of the cross-linked polyperoxides, and the bonded glass joints were successfully debonded without breaking the glass adherends. The failure mode was the cohesive failure of the adhesive and the residue of the cross-linked polyperoxides heavy adhered on the both debonded glass adherends. The additional photoirradiation on the debonded glass adherends in tetrahydrofuran resulted in the significant removal of the adhered cross-linked polyperoxide due to the further photodegradation. After 150 J/cm(2) irradiation, the adhesive residues were completely wiped off from the glass adherends.