Mesoscale dynamic simulation on phase separation between plasticizer and binder in NEPE propellants

It has been found that phase separation between polymer binder and small molecular plasticizer has an important effect on the properties of nitrate ester plasticized polyether (NEPE) propellants. However, the phase separation mechanism and factors of influencing the phase separation have not been clarified yet. To shed some light on this issue, a simple and novel method, that is Dissipative Particle Dynamics (DPD) mesoscale simulation, was used to study the influence of temperature and chains length on the phase separation behavior between binder and plasticizer. The results indicated that the temperature is the key factor in controlling the moving speed of molecules in NEPE propellants system. While the interaction between binder and plasticizer plays an important role on the phase separation. With temperature decreasing, the phase separation takes place later and the extent of phase separation is higher. Within a range, when the length of polymer chains is larger, the occurrence of phase separation is earlier. However, for long chains system, the phase separation is less completely than that of the short chains system when the process reaches equilibrium. (c) 2008 Elsevier Ltd. All rights reserved.