Vinyl monomers bearing chromophore moieties and their polymers. I. Initiation and photochemical behavior ofN-acryloyl-N?-phenylpiperazines and their polymers

Abstract

Two novel acrylic monomers bearing aromatic tertiary amino groups, i.e., N-acryloyl-N′-phenylpiperazine (APP) and N-methacryloyl-N′-phenylpiperazine (MPP) are synthesized by the reaction of N-phenylpiperazine and the corresponding acryloyl chlorides in the presence of triethylamine. They can be polymerized easily by using AIBN as an initiator or photopolymerized without any sensitizer. The photochemical behavior of APP, MPP, and their polymers are explored by recording the fluorescence spectra in solution. It has been found that the fluorescence intensities of these monomers are dramatically lower than those of their polymers in the same chromophore concentration, and such phenomenon is termed as “structural self-quenching effect” (SSQE). The strong fluorescence of these polymers can be quenched by adding electron-deficient monomers which have no chromophore moieties such as MMA, AN, etc., and their Stern–Volmer constants are determined. It is observed that the higher the electron-deficiencies of the quenchers, the higher the Stern–Volmer constants, which means stronger quenching effect. The SSQE displayed by APP and MPP make them useful as probes to pursue their photopolymerization process. As polymerizable aromatic tertiary amines, APP and MPP themselves or combining with organic peroxides such as BPO can initiate the photopolymerization or thermal polymerization of vinyl monomers such as MMA, AN by free radical nature, and at the same time enter the polymer chain. © 1996 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 34:1881–1888, 1996