Macromolecular Rapid Communications
M. Atilla Tasdelen, Baris Kiskan, Yusuf Yagci
Free radical polymerization of methyl methacrylate (MMA) is initiated upon irradiation at > 350 nm in CH2Cl2 solution containing benzoxazine (P-a) and one of the following photosensitizers: benzophenone (BP), thioxanthone (TX), (CTX), 2-isopropyl-thioxanthone (ITX) and camphorquinone (CQ). The postulated mechanism is based on the intermolecular reaction of excited photosensitizer with the tertiary amino moiety of the ground state P-a and subsequent hydrogen abstraction reaction. The resulting aminoalkyl radicals initiate the polymerization. Incorporation of P-a groups into polymers was demonstrated by spectroscopic methods. The possibility of deep curing using described photoinitiating system followed by the thermal ring opening of the incorporated P-a groups was also demonstrated.