Photoinitiator‐free photopolymerization of acrylate‐bismaleimide mixtures and their application for inkjet printing

There is growing interest in using photoinitiator‐free systems in coating applications such as inkjet‐printing, because residual photoinitiator can alter the properties of the resulting polymer. Bismaleimides (BMI) offer the opportunity to polymerize acrylates without the addition of photoinitiators, as this class of molecules can serve both as polymerizable monomer and as photoinitiator together with electron donor systems, like vinyl ether monomers or acrylates. The UV‐induced copolymerization of a low‐molecular‐weight BMI with various acrylate monomers and oligomers without any photoinitiator was characterized. The BMI‐acrylate systems show comparable polymerization speeds to widely used acrylic systems with photoinitiator. Superior thermal stability as well as thermomechanical properties are achieved by enhancing acrylics with BMI. Such photoinitiator‐free systems lend themselves to be used for low‐migration coatings as well as for high‐temperature applications. Here, a characterization of selected BMI‐acrylate mixtures regarding their photocuring kinetics and their application as inks for inkjet printing is shown.