Molecular dynamics simulation of TNT/PYRN cocrystal PBXs

Area of Science:

• Energetic Materials Science
• Computational Chemistry
• Polymer Science

Background:

• The trinitrotoluene (TNT)/pyranidine (PYRN) eutectic system offers a less sensitive, moderate-energy explosive alternative.
• Investigating polymer-bonded explosives (PBXs) based on TNT/PYRN is crucial for understanding structure-property relationships.
• Limited research exists on the intrinsic causes of property changes in eutectic explosives.

Purpose of the Study:

• To theoretically model the TNT/PYRN eutectic system integrated with various polymer additives.
• To elucidate the influence of polymer matrices on the structural integrity, initiation properties, and mechanical behavior of PBXs.
• To identify the optimal polymer binder for TNT/PYRN-based PBXs.

Main Methods:

• Molecular dynamics (MD) simulations were performed using Materials Studio.
• The COMPASS empirical force field was employed with a 1 fs time step over a 2 ns NPT ensemble simulation at 295 K.
• Five distinct cleavage planes within the eutectic matrix were explored for polymer integration.

Main Results:

• Polymer-bonded explosives (PBXs) were successfully synthesized by incorporating polymers into the TNT/PYRN eutectic system.
• The TNT/PYRN/F2603 configuration exhibited the highest binding energetics and shortest critical bond lengths, indicating superior stability.
• The TNT/PYRN/F2603 system demonstrated enhanced explosive initiation capability and superior overall performance metrics.

Conclusions:

• F2603 is identified as a preferential binder for TNT/PYRN eutectic-based PBX formulations.
• The integration of F2603 enhances the stability, interfacial compatibility, and initiation performance of the explosive composite.
• This research provides valuable insights into the design of low-vulnerability and high-performance energetic materials.