Facilely prepared blue-green light sensitive curcuminoids with excellent bleaching properties as high performance photosensitizers in cationic and free radical photopolymerization?

Polymer Chemistry Pub Date: 2018-03-07 DOI: 10.1039/C8PY00166A

Abstract

Curcumin is attractive in photopolymerization especially in cationic photopolymerization, because of its broad absorption and nontoxic properties. Curcuminoid (CMD) is a linear diarylheptanoid and can be considered as a derivative of curcumin. Based on the framework of curcumin, four CMDs containing carbazole/triphenylamine/dimethylaniline/phenothiazine as electron donors and β-diketone as electron acceptors are prepared using a facile synthesis method. The absorption maxima of the prepared CMDs all showed significant red-shifts compared with that of curcumin. The CMDs can act as high performance photosensitizers of iodonium salt (ONI) to start the ring-opening cationic photopolymerization of epoxides and the free radical photopolymerization of acrylates upon blue-green light exposure using light-emitting diodes. Excellent polymerization initiating efficiencies are found, and high final function conversions are obtained. The initiating abilities of the CMDs/ONI can be enhanced in the presence of N-vinyl carbazole or triphenylphosphine. More remarkably, the CMDs/ONI exhibit excellent photobleaching properties, and can be used in deep free radical photopolymerization.

Graphical abstract: Facilely prepared blue-green light sensitive curcuminoids with excellent bleaching properties as high performance photosensitizers in cationic and free radical photopolymerization
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