Synthesis and Characterization of a One‐Component Water‐Soluble Photoinitiator Based on Thioxanthone Derivatives

Thioxanthone derivatives with additional amino groups (TX‐S‐NH 3 ) are synthesized via a simple esterification reaction between TX‐S‐CH 2 ‐COOH and 2‐methylaminoethanol hydrocarbons in a p‐toluene sulfonic acid medium. The TX‐S‐NH 3 is characterized by 1 H NMR, 13 C NMR, FT‐IR, HRMS, ultraviolet‐visible spectrophotometry, and fluorescence spectroscopy. TX‐S‐NH 3 has strong absorption in water and ethanol, and the molar extinction coefficients at 395 nm are 2800 and 2780 mol −1 L cm −1 , respectively. TX‐S‐NH 3 shows a low fluorescence quantum yield of 0.109 in deionized water. The maximum mobility of TX‐S‐NH 3 in the photocuring product in ethanol is 12.5%. The double bond conversion of TMPTA cured by TX‐S‐NH 3 is 60.7% without co‐initiator. TX‐S‐NH 3 has excellent curing effects in UV‐curable ink with a light curing time of only 2.3 s.