1. Development of a Light-Deactivatable PSA Via Photodimerization.
- Author
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Trenor, Scott R., Long, Timothy E., and Love, Brian J.
- Subjects
- *
COUMARINS , *PRESSURE-sensitive adhesives , *GUMS & resins , *POLYMERS , *ADHESIVES - Abstract
Photoreactive pressure-sensitive adhesives (PSAs) were developed to create photodeactivatable resins. Coumarin-functionalized poly(2-ethylhexyl acrylate-co-hydroxyethyl acrylate) was prepared via traditional free-radical polymerization followed by quantitative hydroxyl group esterification and studied as model photoactive PSAs. The polymers were solution-cast into films and photocrosslinked via dimerization of the coumarin derivatives with ultraviolet-A (UVA) light irradiation (> 300 nm). Ultraviolet-Visible (UV-Vis) spectroscopy indicated that approximately 60% of the coumarin groups photodimerized when exposed to 22 J cm -2 of UVA irradiation. The formation of reversible coumarin crosslinks gelled the model PSA and reduced peel strength from 1.62 to 0.05 N/mm. UVC irradiation photocleaved the coumarin dimers, reducing the crosslink density and raising the peel strength to 0.10 N/mm. This reversibility of the coumarin photodimerization and consequent peel-strength modulation may provide a mechanism for the repeated use of these model adhesives. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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