Experimentally Informed Development of a Bismaleimide (BMI) Resin Cure Process Simulation

Bismaleimide (BMI) resins are an increasingly common polymer matrix material for fiber reinforced composites due to their excellent thermo-mechanical properties and oxidative stability. However, BMI monomers undergo a complex combination of curing reactions, which results in a currently incomplete understanding of the process-structure-property relationships for BMI resins and BMI matrix composites. This work presents a reactive molecular dynamics (MD) simulation of the cure process for a BMI resin, which captures the complex and process-sensitive properties of the resin network using a parallel cure model. Network formation in the simulation is compared to the experimental extent of cure measured by spectroscopy, as well as experimental gel fraction measurements. Volumetric shrinkage, Young's modulus, shear modulus, yield strength, and Poisson's ratio are additionally predicted in MD and compared to experimental values. The developed model is used to create a virtual processing cycle, which can underpin physics-informed cure process optimization and multiscale modeling of composite materials.