NEPE推进剂/衬层界面研究进展

Recent advances on research of adhesive interfaces between NEPE propellants and HTPB liner

装药界面是固体火箭发动机故障高发部位。NEPE固体推进剂活性组分多,界面化学物理过程复杂,装药界面粘接问题更加突出。重点开展了界面结构表征、界面粘接与老化失效机理两个方面的研究,发现NEPE推进剂/衬层界面区域在微观尺度上存在多层次结构,推进剂一侧形成40~80μm的HMX及其键合剂富集区,衬层HTPB粘合剂向NEPE推进剂方向扩散,在物理分界衬层侧形成粘合剂基体富集层。系统分析了影响界面粘接的主要因素,确定了影响界面粘接的主反应,阐明了两个主反应的竞争关系。揭示了界面粘接的主要副反应,即工艺助剂YS与固化剂的反应。发现了NEPE推进剂/衬层粘接界面老化降解的关键化学过程,界面老化降解主要发生在PEG与N100反应形成的氨基甲酸酯结构的C—O键,氮氧化物的残余含量决定老化反应的速率。

Propellant-liner interfaces are the high-risk area of solid rocket motor faults.The interfacial adhesion problem of nitric ester plasticized polyether（ NEPE） propellants-liner is especially evident,because there are very complex chemical and physical interactions at the propellant-liner interface area.This paper summarizes two key problems in the propellant-liner interface research,which are micro-structure characterization and adhesion/aging mechanism of the propellant-liner interface. The chemical compound distribution and micro-structure of the interface have been illuminated.There is a 40 ～ 80 μm layer enriched with HMX and its bonding agent.Liner binder diffuses to NEPE propellant,and a binder enriched layer is formed at liner side of physical interface.The main factors which affect interfacial adhesion have been investigated,and then the two main reactions of the interface adhesion have been extracted. Moreover,the effect on adhesion of their competition has been explained in detail. The key side reaction of the interface adhesion has been detected.It is the reaction between processing aids YS and curing agent.The key chemical process of the interface aging reactions has also been found out.The weakness of interface aging is the bonding C-O of carbamate groups formed by the reaction between PEG and N-100,while the aging rate depends on the residual nitrogen oxide content in the interfacial layer.