VINYL MONOMERS BEARING CHROMOPHORE MOIETIES AND THEIR POLYMERS .2. FLUORESCENCE AND INITIATION BEHAVIOR OF N-(4-N',N'-DIMETHYLAMINOPHENYL)MALEIMIDE AND ITS POLYMER

A maleimide bearing electron-donating chromophore, N-(4-N',N'-dimethyl aminophenyl)maleimide (DMAPMI) was synthesized from N,N-dimethylaminoa niline and maleic anhydride in the presence of acetic anhydride and so dium acetate. DMAPMI can be easily copolymerized with vinyl acetate (V Ac). In addition, it can be easily homopolymerized by UV light irradia tion or by using AIBN or BPO as an initiator. The fluorescence spectra of DMAPMI and its polymer or copolymer were recorded and compared at the same chromophore concentrations. It was observed that the fluoresc ence emission intensity of DMAPMI was much lower than those of its pol ymers. This may be due to the occurrence of intermolecular charge tran sfer interaction between the electron-donating dimethylaminophenyl moi ety and acrylic electron-accepting carbon-carbon double bond in the mo nomer. The model compound, N-(4-N',N'-dimethylaminophenyl)succinimide (DMAPSI), which has no carbon-carbon double bond, displayed the same f luorescence behavior as DMAPMI polymers. The fluorescence of DMAPMI po lymers and DMAPSI can be quenched by electron-deficient compounds such as AN, TCNE, MMA, etc. All these results supported the above conclusi on. This is another example of the ''fluorescence structural self-quen ching effect'' termed by us previously and demonstrates again that thi s phenomenon is not an accidental but a general one for acrylic monome rs bearing electron-donating chromophores. Study of the initiation beh avior of DMAPMI and its polymer showed that they could initiate the ph otopolymerization of AN, by combination with BPO, they could also init iate the thermopolymerization of vinyl monomers such as MMA. (C) 1996 John Wiley & Sons, Inc.