End-group analysis of polymers by electrospray ionization mass spectrometry: 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one initiated free-radical photopolymerization

End-group analysis of poly(methyl acrylate) and poly( dicyclohexyl itaconate) initiated by 2-methyl-1-[4-(methylthio) phenyl]-2-morpholinopropan-1-one (MMMP) has been performed by electrospray ionization mass spectrometry (ESI-MS). MMMP has been found to fragment into two radicals that are near-equally capable of initiating free-radical polymerization processes. The present study indicates the occurrence of significant termination by disproportionation in the polymerization of methyl acrylate. Additionally, it has been demonstrated that dicyclohexyl itaconate undergoes termination by disproportionation almost exclusively