Synthesis of Photo-degradable Polyphthalaldehyde Macromonomer and Adhesive Property Changes of its Copolymer with Butyl Acrylate on UV-irradiation

We prepared a new polyphthalaldehyde (PPA) macromonomer by introducing a polymerizable methacryloyl group at the terminal of PPA main-chain. Resulting macromonomer was copolymerized with butyl acrylate to obtain pressure-sensitive adhesives (PSAs). We also compared the behavior of the copolymers with those of polymer blends of poly(butyl acrylate) and linear PPA polymers to clarify the role of polymerization. Higher peel strengths were observed for copolymers than those of corresponding polymer blends. As an increase in irradiation time, the strength generally decreased, although once increased for the copolymer films at the early stage. These results suggest that the introduction and the depolymerization of PPA side-chains caused drastic changes in adhesive properties.