Visible-Light-Sensitive Polymerizable and Polymeric Triazine-Based Photoinitiators with Enhanced Migration Stability

Abstract

Photopolymerization has attracted great interest because of its mild reaction conditions, spatiotemporal controllability, cost efficiency, and fast speed. However, with the raising environmental awareness and the increasing attention to life and health, the leachability of photoinitiators has become a growing concern. In this research, a methacrylate functionalized triazine-based polymerizable visible light photoinitiator, 2-(((4-(2-(4,6-bis(trichloromethyl)-1,3,5-triazin-2-yl)vinyl)phenoxy)carbonyl)amino)ethyl methacrylate (CT) and its reversible addition–fragmentation chain transfer (RAFT) polymerized CT (pCT) were designed as the polymerizable and polymeric photoinitiators, respectively. The photoinitiation abilities of the investigated triazine derivatives were evaluated under violet LEDs. Due to the steric effect, pCT showed slightly reduced photoinitiation ability under both LED at 400 nm and 410 nm irradiation. Nevertheless, photopolymers initiated using CT and pCT showed excellent migration stability compared to those prepared by 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine (MT) and 4-(2-(4,6-bis(trichloromethyl)-1,3,5-triazin-2-yl)vinyl)phenol (PT). Specifically, CT and pCT-based polymers prepared under the irradiation of LED at 400 nm exhibited only 1/3-fold and 1/14-fold of photoinitiators leachability, while 1/2-fold and 1/6-fold of photoinitiator leachability were obtained compared to the MT-based photocured polymers when using LED at 410 nm. The excellent migration stability of pCT reveals potential applications in the biomedical and food packaging fields.