Molecular dynamics study of the shock response of polyurea

We leverage the phase segregated microstructure of polyurea to study its shock response using molecular dynamics (MD) simulation. The two phase segregated domains, the hard and the soft domains, are investigated separately. The shock response of the domains is studied using a multiscale shock-simulation approach that allows simulation of low pressure shocks. Both domains exhibit an unconventional behavior at low shock velocities that is typically associated with polymers. The shock response of the hard domain is marked by energy dissipation due to hydrogen bond breaking. Moreover, the radial distribution function suggests a severe distortion in the ring structure of aromatic moieties in the hard domain at high shock pressure. Finally, the shock Hugoniot of polyurea, obtained by combining the response of the two domains using a mixing rule, shows excellent match with experimental data