Influence of Aspect Ratio and Microstructure on Thermal Characteristics of Needle-Like Nitroguanidine

Abstract. Nitroguanidine (NQ) is a well-known energetic material whose solid-state properties are strongly influenced by its crystallization behaviour and resulting crystal morphology. Under conventional crystallization methods, NQ dominantly forms long, needle-like crystals characterized by high aspect ratio. These morphological features are known to influence key physicochemical attributes, including thermal stability and sensitivity characteristics. Despite extensive use of NQ, systematic investigations addressing how controlled variations in needle aspect ratio affect these characteristics remain limited. Therefore, a deeper analysis of NQ crystals with varying aspect ratios is essential to establish clearer correlations between morphology, thermal behaviour and physicochemical properties, thereby contributing to a more fundamental understanding of structure-property relationships in energetic crystalline materials. This work focuses specifically on the role of aspect ratio within needle-like NQ crystals as a controllable morphological parameter. Using a controlled-crystallization approach, NQ samples with varying aspect ratios (length/diameter) will be prepared and characterized. Morphological measurements will be obtained via Optical Microscopy and SEM, while BET analysis will quantify surface area and porosity effects correlated with aspect ratio. Thermal properties will be characterized by DSC/TGA. Mechanical sensitivity will be investigated with BAM/Friction tests to complete the characterisation of the samples. By establishing quantitative relationships between aspect ratio and structural/thermal behaviour, this research aims to deepen understanding of morphology-driven performance in NQ and lay groundwork for targeted morphology engineering. The findings will inform safer utilization strategies for needle-dominant nitroguanidine systems. Experimental work is ongoing and initial results will be presented at the conference.