Preparation of CL-20 with Controllable Particle Size Using Microfluidic Technology

Area of Science:

• Materials Science
• Chemical Engineering
• Energetic Materials

Background:

• CL-20 (hexanitrohexaazaisowurtzitane) is a high-energy-density material with limited applications due to sensitivity.
• Microscopic structural adjustments are key to overcoming CL-20's sensitivity limitations.

Purpose of the Study:

• To prepare ε-CL-20 with controlled particle sizes using microfluidic recrystallization.
• To investigate the impact of particle size on CL-20's properties, including sensitivity, density, and combustion behavior.

Main Methods:

• Microfluidic recrystallization was employed to synthesize ε-CL-20.
• Three distinct particle size distributions were achieved (D50 = 2.77 μm, 17.22 μm, and 50.35 μm).
• Characterization included analysis of surface defects, density, impact sensitivity, activation energy, and laser ignition performance.

Main Results:

• Microfluidic preparation yielded CL-20 with fewer surface defects compared to the raw material.
• Decreasing particle size increased CL-20 density and significantly reduced impact sensitivity.
• Smaller particles demonstrated higher energy release efficiency, while larger particles offered more stable energy release.
• Activation energy increased with particle size for microfluidic-prepared CL-20.

Conclusions:

• Microfluidic recrystallization enables controllable preparation of various CL-20 particle sizes, improving crystal size distribution and surface morphology.
• Optimizing CL-20 crystal size enhances both combustion performance and safety.
• This technique provides a valuable reference for producing other energetic materials with tailored particle sizes.