Molecular dynamics simulation of DNAN/DNB cocrystal PBXs

Area of Science:

• Materials Science
• Chemical Engineering
• Computational Chemistry

Background:

• DNAN/DNB eutectic offers superior safety and thermal stability over traditional melt-cast explosives.
• Polymer binders are crucial for enhancing the mechanical properties of energetic materials like DNAN/DNB.
• Developing polymer-bonded explosives (PBXs) is key to meeting production demands without altering existing infrastructure.

Purpose of the Study:

• To model and predict the properties of DNAN/DNB eutectic explosives with various polymer binders.
• To evaluate the impact of different polymers on the stability, mechanical properties, and detonation performance of DNAN/DNB.
• To identify the optimal polymer binder for DNAN/DNB-based PBXs.

Main Methods:

• Molecular dynamics (MD) simulations were performed using Materials Studio.
• Simulations utilized a timestep of 1 fs and a total duration of 2 ns under NPT ensemble.
• The COMPASS force field was applied at a constant temperature of 295 K.

Main Results:

• The DNAN/DNB/PEG model exhibited the highest binding energy and shortest trigger bond length among the five tested PBXs.
• PEG addition significantly improved the stability, compatibility, and sensitivity of the DNAN/DNB eutectic.
• While binder addition slightly decreased detonation performance, the overall results for DNAN/DNB/PEG remained satisfactory.

Conclusions:

• Polyethylene glycol (PEG) is identified as the optimal polymer binder for DNAN/DNB eutectic explosives.
• The DNAN/DNB/PEG PBX demonstrates excellent comprehensive performance, balancing stability and energetic properties.
• This research provides valuable insights into the design of safer and more effective polymer-bonded explosives.