抄録
Mono- (1), di- (2), and trifunctional (3) O-acyloximes were prepared as novel photobase generators (PBGs) from mono-, di-, and trioximes based on 1,3,5-triacetylbenzene, respectively, and these PBGs and acetophenone O-phenylacetyloxime (4) were compared from the viewpoint of physical, photochemical properties, and crosslinking ability of poly(glycidyl methacrylate)(PGMA). Thermal decomposition temperatures of the PBGs were higher than 200 °C showing good thermal stability. Absorption maxima of PBGs shifted to shorter wavelength as an increase in the number of acetyl groups. Product analysis suggested the photo-degradation of 3 into 1,3,5-triacetylbenzene via 2 and 1. Quantum yields of photolysis of PBGs at 254 nm in acetonitrile were estimated to be around 0.3. The lower quantum yield of 1 suggested the inactive effect of electron withdrawing substituents on the reactivity of excited acyloxime moiety. The yields of benzylamine in polymethacrylonitrile (PMAN) films were analyzed by HPLC after derivatization, and multifunctional PBGs tended to give higher yields than monofunctional ones. However, the yield of benzylamine based on acyloxime unit was in the order 1 > 2 > 3 ∼ 4. PGMA films containing PBGs became insoluble on irradiation after heating due to the addition reaction of the generated amine and epoxy groups in PGMA. The degree of the insolubilization corresponded to the yields of photo-generated benzylamine in PMAN films, showing the apparent advantage of multifunctionality.
