Thioxanthone based one-component polymerizable visible light photoinitiator for free radical polymerization

Abstract

An acrylate functionalized thioxanthone based one-component polymerizable visible light photoinitiator, 4-((methyl(9-oxo-9H-thioxanthen-2-yl)amino)methyl)phenyl acrylate (TX-PA) has been designed and synthesized and its structure has been confirmed by ¹H NMR, ¹³C NMR and MS. TX-PA could successfully initiate photopolymerization of 1,6-hexanedioldiacrylate (HDDA), trihydroxymethylpropyl triacrylate (TMPTA) and pentaerythritol triacrylate (PETA) under xenon light exposure (λ > 400 nm) both in the presence and absence of N-methyldiethanolamine (MDEA). The synergistic effect of the acryloxy group and tertiary amine in the thioxanthone molecule helps TX-PA exhibit a higher photopolymerization activity and better migration stability than that of 2-(benzyl(methyl)amino)-9H-thioxanthen-9-one (TX-B). The results demonstrate that TX-PA is an effective one-component polymerizable visible light photoinitiator for free radical polymerization with excellent migration stability, which has great potential to be widely used in the food packing or biomedical fields.