预应变对HTPB推进剂老化动态力学性能的影响
Effect of Prestrain on Dynamic Mechanical Properties of HTPB Propellant during Aging Process

针对HTPB复合固体推进剂开展了70℃热力耦合加速老化试验，采用动态热机械分析仪测定了不同预应变老化作用下HTPB推进剂的动态力学参数，获得并分析了推进剂的储能模量、损耗模量及力学损耗温度谱等参数。结果表明，老化过程中预应变对HTPB推进剂动态力学性能有较大影响。在相同老化时间，随预应变的增大，HTPB推进剂高分子链柔性降低，玻璃化温度升高，玻璃化松弛活化能增大，力学损耗增大。无预应变老化条件下，随老化时间的增加，HTPB推进剂力学损耗降低，黏合剂氧化交联起主导作用，而15%预应变老化条件下，随老化时间的增加，HTPB推进剂力学损耗增加，基体损伤及填料/基体界面损伤对推进剂力学损耗起主导作用。
The accelerated aging tests of HTPB (hydroxy-terminated polybutadiene binder) propellant under the interaction of thermal and prestrain were adopted to study the effect of prestrain on the mechanical properties of composite solid propellant. The dynamic mechanical parameters of HTPB propellant at different prestrain levels were obtained through dynamic mechanical tests and the temperature spectra of storage modulus, loss modulus and loss factor were analyzed. The results show that the prestrain during aging process has great influence on the dynamic mechanical properties of HTPB propellant. At the same aging time, with the increase of the prestrain, the flexibility of polymer chain decreases, as a result, the glass transition temperature of HTPB propellant increases. Besides, the activation energy of the glass relaxation process and the mechanical loss increase. For the HTPB propellant aged without prestrain, with the increase of aging time, the mechanical loss of HTPB propellant decreases due to the leading role of the oxidative crosslinking reaction of binder matrix. However, for the HTPB propellant aged under 15% prestrain level, the mechanical loss increases with the increase of aging time. Because the accumulated damage of binder matrix and the damage of interface between filler/matrix plays a dominant role in the mechanical loss of the propellant