Characterization of the Internal Pores of LLM‐105 with Different Particle Sizes Using Contrast Variation Small Angle X‐Ray Scattering

Abstract To study the effect of particle size on the internal pore structure of micro/nano energetic materials, three kinds of micro/nano explosives 2,6‐diamino‐3,5‐dinitropyrazine‐1‐oxide (LLM‐105) with different particle sizes were selected as the research objects. The internal pore structure information, including porosity, pore volume distribution and fractal characteristics of micro/nano LLM‐105 were characterized by contrast variation small‐angle X‐ray scattering (CV‐SAXS). The scattering results show that the power‐law index of three samples with different particle sizes is between 3 and 4 in the measured q range (the surface fractal dimension D s of 200 nm LLM‐105 is 2.16, D s of 500 nm LLM‐105 is 2.20, and D s of 3 μm LLM‐105 is 2.76). With the decrease of particle size, the interface between the internal pores and matrix becomes smooth. The pore volume per unit mass of LLM‐105 increases with the decrease of the particle size. The increase of pore volume per unit mass when the particle size decreases from 3 μm to 500 nm is much larger than that when the particle size decreases from 500 nm to 200 nm. The number of 2.5 nm–40 nm internal pores in LLM‐105 increases with the decrease of particle size. Especially for the pores of 11 nm, the number of pores increases most obviously with the decrease of particle size.