  Predictive computational modeling of polymer materials is necessary for the
efficient design of composite materials and the corresponding processing
methods. Molecular dynamics (MD) modeling is especially important for
establishing accurate processing-structure-property relationships for neat
resins. For MD modeling of amorphous polymer materials, an accurate force field
is fundamental to reliable prediction of properties. Reactive force fields, in
which chemical bonds can be formed or broken, offer further capability in
predicting the mechanical behavior of amorphous polymers subjected to
relatively large deformations. To this end, the Reactive Interface Force Field
(IFF-R) has been recently developed to provide an efficient means to predict
the behavior of materials under these conditions. Although IFF-R has been
proven to be accurate for some crystalline organic and inorganic systems, it
has not yet been proven to be accurate for amorphous polymer systems. The
objective of this study is to use IFF-R to predict the thermo-mechanical
properties of three different epoxy systems and validate with experimental
measurements. The results indicate that IFF-R predicts thermo-mechanical
properties that agree closely with experiment. Therefore, IFF-R can be used to
reliably establish mechanical properties of polymers on the molecular level for
future design of new composite materials and processing methods.
