Fully Atomistic Molecular Dynamics Simulations of Hydroxyl-Terminated Polybutadiene with Insights into Hydroxyl Aggregation

A fully atomistic model designed to reproduce the molecular weight and average functionality typical of commercial hydroxyl-terminated polybutadiene (HTPB) formulations is presented. The structural and dynamical properties of HTPB were investigated utilizing molecular dynamics (MD) simulations. Spatial conformations of the HTPB chains were characterized by using the radius of gyration and end-to-end distance; HTPB chain dynamics were described by the end-to-end vector autocorrelation function. Terminal hydroxyl (OH) groups were found to associate in dynamic aggregates of various sizes. The distribution of the OH aggregate sizes and their relative stabilities were calculated. The significance of OH association in relation to curing reactions is discussed.