Methods to Evaluate Near-Infrared Photoinitiating Systems for Photopolymerisation Reactions Assisted By Upconversion Materials

The photoinitiating systems of upconversion materials-assisted photopolymerization (UCAP) lacks a systematic evaluation method, which significantly limits its applications of high-performance and high-precision materials. Herein, we demonstrate an operable evaluation system for photoinitiating systems selection from the aspects of spectral matching, initiation activity and polymerization ability, or as an instructed strategy for the novel initiation systems development in UCAP process. Ir-784, Om-819, Om-TPO and ITX stand out from the analysis of quantitative initiation systems and have excellent initiation and polymerization performances. Notably, the exogenous heat from the UCAP induced by the NIR laser excellently improves the polymerization ability of the photoinitiating system and the mechanical properties of the final materials. The evaluation method integrated with digital and theoretical research will further extend the versatility of UCAP technology in chemistry "4.0" of developing digital-based production technologies.