Modeling the formation and thermomechanical properties of polybenzoxazine thermosets

We present a comparative molecular modeling study of the thermomechanical properties of crosslinked benzoxazine resins. A crosslinking algorithm was developed in order to simulate the thermal curing of thermoset resins and monitor the evolution of their network topology. The resin properties (gelation point, crosslink density, volumetric expansion, glass transition temperature, thermal expansion coefficient and elastic constants) were probed as a function of the network composition. The simulation results are in line with analytical models and in very good agreement with experimental data. Our molecular dynamics simulations provide a detailed rationale for the differences in the measured thermomechanical properties of recently reported benzoxazine derivatives and pave the way to the design of improved resins using predictive modeling tools based on the monomer chemical structure as the sole input.