Synthesis and polymerization of p-(p′-vinylbenzoyl)-peroxybenzoic acid tert-butylester: A monomer containing a photodissociable radical source

In a previous report we have shown that efficiently photodecomposable, but thermally stable, peresters can be made from a compound that contains both a triplet photosensitizer functionality and a perester group. This fundamental approach has been extended to make a novel vinyl monomer containing a triplet sensitizer and a perester group. Thus, the monomer p-vinylbenzoyl-p-tert-butyl perbenzoate (VBPE) has been synthesized and polymerized by normal procedures without loss of perester activity. The resulting polymer perester can be used as an efficient photolabile radical source by irradiating at the λ_max of the benzophenone carbonyl moiety. The homopolymer (PVBPE) and copolymers with other monomers, such as styrene, could be photocrosslinked with high efficiency. Copolymers of VBPE and styrene containing low percentages of VBPE have been used to initiate graft chains of poly(methyl methacrylate) by irradiating a solution of the copolymer in methyl methacrylate at 366 nm.