Photoinitiators with low migration capability based on benzophenone

Abstract

Due to the increasing safety concerns caused by migration of photoinitiators, the development of low migration photoinitiators has become a priority in the current stage. As a widely used Type II photoinitiator, benzophenone is known to cause the migration of residual small molecule initiators and co-initiators after photopolymerization, leading to safety issues and severely limiting its applications. In this work, a polymerizable photoinitiator (VBP) was synthesized by directly introducing an ethylene group into benzophenone, three different molecular weight single-component photoinitiators PVBN1-3 were synthesized based on VBP. The characterization was conducted by using spectroscopic techniques, revealing stronger absorption ability in the range of 200–330 nm compared to benzophenone. The initiation efficiency of the acrylic monomer by PVBN1-3 was evaluated by using real-time FT-IR technique. The migration stability of the cured system was investigated through immersion extraction. The results demonstrate that VBP and PVBN1-3 are a series of high-performance, low-migration photoinitiators.