Modulation of ADN Crystal Surface Properties by Additives

In this paper, a method to reduce the hygroscopicity of the energetic oxidizer ammonium dinitramide (ADN) was proposed by modulating the surface properties of ADN crystals with additive microdoping. Cyclotetramethylene tetranitramine (octogen, HMX) was selected as the additive, and a three-layer solventization model was constructed based on the adhesion energy theory by placing the additive in the solvent layer. The modified adhesion energies and moisture absorption rates of each ADN crystal surface were calculated under the effects of different solvents and additives. The effects of additives on the crystal growth and crystal morphology of ADN in the presence of different solvents were investigated. The interactions between different solvents and crystalline surfaces were analyzed, and the modification of the attachment energy was calculated. The results showed that utilizing HMX as an additive significantly influenced the ADN crystal morphology, crystal face occupancy, and growth rate in different solvent environments. HMX showed the best antihygroscopicity performance as an ADN additive in a dichloromethane (DCM) solvent environment, and the percentage of antihygroscopic crystal faces on the ADN crystal surfaces increased up to 74.70%.