Enhancement in the initiating activity of chalcones via a long-alkyl chain strategy for free radical photopolymerization and 3D printing

Abstract

A novel chalcone-based derivative, E-PHMTO, equipped with an alkyl chain and chemically similar to the commercial photoinitiator ITX, was successfully synthesized. Compared to the intermediate reaction products E/Z-HMTO, the introduction of an alkyl chain to the chalcone group shifts the focus of E-PHMTO towards proton transfer rather than isomeric side reactions, resulting in an LED-sensitive photoinitiator with excellent initiating performance through steric hindrance. Furthermore, E-PHMTO demonstrated superior initiating activity compared to ITX under LED@385 nm irradiation and proved to possess outstanding polymerization properties suitable for 3D photo-printing applications. This research might offer a versatile approach for the convenient design and preparation of highly efficient, LED-sensitive chalcone photoinitiators.