HTPB/Al/AP/RDX复合推进剂组元之间相互作用研究

Study on Interaction between Component for HTPB/Al/AP/RDX Composite Propellant

为了探索HTPB/Al/AP/RDX复合推进剂组元之间的相互作用,用DSC和TG-DTG方法以及分解反应动力学计算研究了递增组元的4个混合体系(包括HTPB黏合剂体系、HTPB/Al、HTPB/Al/AP和HTPB/Al/AP/RDX推进剂体系)中各组元之间的相互作用。结果表明,DTG峰温以及反应速率常数k可以表征各组元之间的相互作用,其DSC和TG过程可以分为3个阶段;除Al外,各组元之间存在相互作用,各阶段的质量损失测定值与按组分含量计算的加合值吻合得相当好,表明各组元并没有明显的跨阶段分解;AP与HTPB黏合剂的分解温度区间接近或部分重叠,在HTPB/Al/AP和HTPB/Al/AP/RDX的混合体系中发生了强烈氧化还原作用:四组元体系中RDX在200℃及220℃的速率常数k分别为1.53和6.81s-1,均大于单质RDX在同一温度下的速率常数1.33×10-6和1.06×10-5s-1,说明AP可以加速RDX的分解,但RDX对AP或(AP+HTPB)分解的影响呈现复杂的情况,由于HTPB/Al/AP和HTPB/Al/AP/RDX两体系中AP与HTPB的共同分解过程中存在“等动力学点”(308.0℃),温度低于此点时(AP+HTPB)分解速率常数k因RDX存在而下降,而当温度高于此点时则该k值因RDX存在而增大。通过RDX分解机理解释了存在这种现象的原因。

In order to study the interaction between composite propellant components,four hybrid systems of progressive components(HTPB binder system,HTPB/Al,HTPB/Al/AP and HTPB/Al/AP/RDX)were investigated.The interactions between components were studied through DSC,TG-DTG methods and kinetic calculations.The results showed that the DTG peak temperature and reaction rate constant(k)could characterize the interactions between the components.Corresponding DSC and DTG processes were divided into three stages.Except Al,there were interactions between different components and the measured value of mass loss at each stage agreed well with the sum of the calculated contents of the components with no obvious cross-stage decomposition observed.The decomposition temperature range of AP and HTPB was close or partially overlap,and strong redox occurs in the hybrid system of HTPB/Al/AP and HTPB/Al/AP.The rate constant of RDX at 200℃and 220℃in the quaternary system were 1.53s-1and 6.81s-1,which were greater than that of elemental RDX at the same temperature,incdicating that AP could accelerate the decomposition of RDX while the role of RDX in the decomposition of AP or(AP+HTPB)proved to be complicated.Isokinetic point(308.0℃)existed in the decomposition process of AP and HTPB for HTPB/AI/AP and HTPB/AI/AP/RDX systems.Due to the present of RDX,the decomposition rate constant of(AP+HTPB)decreased when the heating temperature is lower than isokinetic point but increased when the heating temperature was higher than isokinetic point.The reason for this phenomenon was further explained based on the decomposition mechanism of RDX.