Curing kinetics of dually-processed acrylate-epoxy 3D printing resins

In this work, the curing kinetics of a new ternary acrylate/epoxy/anhydride thermoset system which is used for dual-curing 3D-printing applications is studied. The first curing stage is an acrylate free-radical photo-polymerization that can also be triggered using a suitable thermal radical initiator. The second curing stage is an epoxy-anhydride copolymerization initiated at higher temperatures by a nucleophilic tertiary amine. Isothermal acrylate photocure kinetics was modeled using a first order rate expression. The thermal curing of both reaction stages was studied under by non-isothermal integral isoconversional and model fitting methods. Furthermore, they were successfully reproduced using a simulation based on the obtained kinetic parameters. Reduced master curves and isokinetic relationships were used to validate the kinetic model selected and the reliability of the employed methodology. The conditions for obtaining a thermal and sequential dual curing can be established with the help of isokinetic temperature.