The optimization of extrusion of energetic materials is a complex topic that requires the knowledge of the material behaviour in the processing conditions selected for this forming process. During the rheological characterization of multi-base colloidal propellants (nitrocellulose gels), certain mechanisms, such as apparent wall slip and loss of solvents, provoke a significant distortion on the rheological results. Although there are some specific procedures based on correcting the wall slip or quantifying the rate of solvent evaporation, this work provides a new analysis of these phenomena for double-base gelled propellants that can help to improve the rheological characterization of these materials. In the present work the concept of “transition layer” is introduced for describing the migration effects related to the loss of solvents that are originated inside the material sample, which provides a better understanding of the viscoelastic response of these concentrated suspensions when rotational rheology with parallel plate geometry is applied. In addition, the control of the normal force exerted during the rotational rheology testing is assumed in this work to analyse the influence of the above-mentioned mechanisms. This analysis of the rheological behaviour of these energetic materials is the basis for the modelling and optimization of the extrusion process, though a deeper knowledge of specific mechanisms of the propellant doughs visco-elasto-plastic response inside the extrusion channels must be developed.

高能材料挤出的优化是一个复杂的主题，需要了解在为该成型过程选择的加工条件下的材料行为。在多碱胶体推进剂（硝化纤维素凝胶）的流变学表征过程中，某些机制（例如明显的壁滑和溶剂损失）会引起流变结果的显着变形。尽管有一些基于校正壁滑或量化溶剂蒸发速率的特定程序，但这项工作为双基胶凝推进剂的这些现象提供了新的分析方法，可以帮助改善这些材料的流变性。在本工作中，引入“过渡层”的概念来描述与材料样品内部起源的溶剂流失相关的迁移效应，这可以更好地理解这些浓缩悬浮液的粘弹性响应，当旋转流变与平行应用板的几何形状。另外，在这项工作中假设控制旋转流变测试过程中施加的法向力，以分析上述机制的影响。对这些高能材料的流变行为的分析是建模和优化挤压过程的基础，尽管必须深入了解推进剂面团在挤压通道内的粘弹塑性响应的具体机理。