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A series of acrylic oligomer which can undergo self‐initiation under UV irradiation were synthesized by Michael addition of acetylacetone (acac) with multi‐functional acrylates using diazabicycloundecene as catalyst. GC‐MS and proton NMR were employed to study the photolysis mechanism of model molecule which was prepared from acac and ethyl acrylate. The β‐diketone moiety attached to a fully substituted carbon atom was photoscissile and prone to produce alkyl free radicals by losing acetyl free radical. Polymerization of the acrylated β‐diketone‐containing oligomers can be thus efficiently triggered regardless of solely irradiated under UV light or blended with pure trimethylolpropane triacrylate. As determined with photo‐DSC, the acrylated β‐diketone‐containing oligomers photopolymerized more slowly than the traditional system of trimethylolpropane triacrylate containing Darocur 1173 at the early stage, but reached a higher final conversion. The rheology measurement showed that the synthesized acrylated β‐diketone‐containing oligomers exhibited shear thinning property. POLYM. ENG. SCI., 47:1082–1090, 2007. © 2007 Society of Plastics Engineers

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Organic–inorganic hybrid UV‐curable coatings were synthesized through blending UV‐curable components and stabilized titania sol prepared via a sol–gel process of tetrabutyl titanate (TBT) with three different stabilizers, acetylacetone (Acac), isopropyl tri(dioctyl)pyrophosphato titanate coupling agent (TTPO) and a polymerizable organic phosphoric acid (MAP). The size and the dispersion of titania particle in the UV‐cured organic matrix were dominated by the properties of these stabilizers. A cured hybrid film with titania particle size around 20 nm was obtained when TTPO was utilized as protection agent for the sol. It is interesting that the hardness and flexibility of the photocured hybrid films were improved simultaneously, in contrast to results with neat organic UV‐curable formulations. Copyright © 2006 Society of Chemical Industry