ABSTRACT

A new kind of macrophotoinitiator (MPI) was synthesized through the copolymerization of acrylic monomers and the polymerizable photoinitiator monomer 2959-AA. Monomer 2959-AA was obtained by an esterification reaction between acrylic acid (AA) and the water-soluble photoinitiator Irgacure 2959 [2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone]. By adjusting the monomer proportions in the MPIs, two series of MPIs with different 2959-AA contents and different glass transition temperatures were obtained. The molecular structure of 2959-AA was characterized by Fourier-transform infrared spectroscopy, nuclear magnetic spectrometry, and mass spectrometry. Polymerization of 1, 6-hexanediol diacrylate was initiated using Irgacure 2959 and 2959-AA, and two series of MPIs to be polymerized were studied with a photo-DSC test. Results showed that 2959-AA had higher chemical reactivity than Irgacure 2959 because of the higher solubility of the former. It was evident from the experiments that 2959-AA content in the MPI progressively increased the polymerization rate and monomer conversion when the glass transition temperatures of MPIs were similar. At the same 2959-AA content, the polymerization rate slightly slowed down with increased glass transition temperature. However, the radical lifetime and polymerization time were prolonged. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40352.