Thermomechanical Property Prediction of a Bismaleimide Resin Using Molecular Dynamics
Abstract
Bismaleimide (BMI) resins have seen increased use as a thermoset polymer matrix material in structural aerospace composites as a result of their excellent thermomechanical properties and low specific weight that arise from the complex structural features of the BMI matrix. Since the development of high-performance composites has increasingly relied on molecular modeling to predict polymer processing characteristics, the ability to effectively model these materials is imperative. Molecular models offer insights into residual stresses and bulk properties of the composite matrix polymer, which directly impact the laminate's durability and performance when subject to thermal and mechanical loads. Unfortunately, its complex crosslink structure has limited the structure-property understanding of BMI at the molecular level, complicating modeling attempts at all length scales. This study utilizes molecular-scale simulations to model a BMI thermoset resin commonly used in aerospace composites at the nanoscale to predict the properties of the bulk thermoset. Molecular dynamics (MD) simulations using the interface force field (IFF) are performed on BMI resins to describe a likely crosslink structure and to evaluate thermomechanical properties as a function of temperature and crosslink density. These properties are then validated against experimental data to ascertain the model accuracy and demonstrate that molecular modeling methods can be successfully used to predict the evolution of properties in the BMI resin during its curing.