SC-CO_(2)辅助挤出成型过程中双基发射药的流变特性

Rheological Property of Double-base Propellant in SC-CO_(2)Assisted Extrusion Process

为了部分替代在发射药挤出成型过程中使用的有机溶剂,将超临界二氧化碳(Supercritical Carbon dioxide,SC-CO_(2))引入发射药的挤出成型过程中,借助其在临界点附近急剧变化的溶剂特性,实现增塑后可快速从产品中驱除,为最终实现SC-CO_(2)对有机溶剂的完全替代做铺垫。以剪切黏度为反映流变特性的参数,采用在线狭缝流变仪测量物料的剪切黏度并获得流变曲线,对物料在不同工艺条件下的流变特性进行研究。研究结果表明:SC-CO_(2)辅助双基药挤出成型过程中物料的流变行为可以用幂律模型描述,引入SC-CO_(2)后物料黏度显著降低,SC-CO_(2)在4.67 wt%含量下使得双基药的稠度系数降低17.10%,体现了SC-CO_(2)对于双基药的良好增塑作用;随着SC-CO_(2)含量、溶剂含量、温度等参数值持续升高,继续增大参数值所能提供的增塑效果将变得有限。

To partially substitute the organic solvents used in the extrusion process of propellant,supercritical carbon dioxide(SC-CO_(2))was introduced into the extrusion process of propellant.Owing to its solvent properties that sharply changing near the critical point,SC-CO_(2)is rapidly removed from the product after plasticization,paving the way for the complete replacement of organic solvents by SC-CO_(2).Shear viscosity is adopted as a parameter to reflect the rheological property,and an in-line slit rheometer is used to measure the shear viscosity of material and obtain the rheological curves to investigate the rheological properties of material under various process conditions.The results indicate that the rheological behavior of material in the extrusion process of SC-CO_(2)assisted double-base propellant can be described by power-law model.The viscosity of material decreases significantly due to the introduction of SC-CO_(2).And the introduction of SC-CO_(2)decreases the viscous coefficient of double-base propellant by 17.10%at the content of 4.67 wt%,reflecting the excellent plasticizing effect of SC-CO_(2)on the double-base propellant.The plasticizing effect provided by increasing the parameter values is limited as the process parameters such as SC-CO_(2)content,solvent content,and temperature increase.