HTPB推进剂用季铵盐高效降速剂研究

Research on quaternary ammonium salts used as high⁃efficiency burning rate suppressants in HTPB propellant

低燃速、高比冲端羟基聚丁二烯(HTPB)推进剂是先进固体火箭发动机发展的重要方向,针对HTPB推进剂用传统降速剂的降速效率不高,且容易造成推进剂能量损失等问题,设计合成了以NF_(2)SO_(3)^(-)、CF_(3)SO_(3)^(-)、BF4-、ClO_(4)^(-)为阴离子的含有长链烷基的新型季铵盐降速剂。对这些降速剂进行了SEM和DSC表征、燃速测试及量子化学计算,研究了它们抑制高氯酸铵(AP)分解和降低HTPB推进剂燃速的作用规律,探讨了高氯酸根季铵盐的降速机理。结果表明,这些季铵盐降速剂对AP的热分解均具有一定的抑制作用,与添加相同含量(1%)草酸铵的推进剂燃烧性能相比,它们的降速幅度提升均超过4.5%,降速效果最好的BPE-1524CD的降速幅度提升达到10.43%;在相同燃速条件下,添加BPE-1524CD降速剂的推进剂燃烧残渣比添加草酸铵的降低了50%,比冲提高了10~20 N·s/kg;三种高氯酸根季铵盐降速剂均易吸附于AP表面,由它们调控的HTPB推进剂的燃速与这些降速剂的导热系数有正相关性。

Developing a hydroxyl-terminated polybutadiene(HTPB)propellant with a low burning rate and a high specific impulse is a crucial focus in advanced solid-fuel rocket motors research.Aiming at the low efficiency of traditional burning rate suppressants in HTPB propellant and the associated energy loss,a new series of quaternary ammonium salts containing long-chain alkanes with NF_(2)SO_(3)^(-),CF_(3)SO_(3)^(-),BF_(4)^(-)and ClO_(4)^(-)as anions were designed and studied.Comprehensive characterization analysis by SEM and DSC,combustion performance determination and quantum chemistry calculations were conducted on these compounds.The effect of these quaternary ammonium salts on the thermal decomposition of ammonium perchlorate(AP)and the combustion regulation performance in HTPB propellant was investigated.The burning rate suppressing mechanism of quaternary ammonium per-chlorate was also analyzed.The results show that these quaternary ammonium salts effectively suppress the thermal decomposition of AP.Compared with combustion performance of the propellant added the same content(1%)of ammonium oxalate,the suppression amplitude for the burning rate of these compounds increased by more than 4.5%.Among the quaternary ammonium salts investigated in this study,BPE-1524CD is the most effective burning rate suppressant,and its suppressing amplitude increases by 10.43%.For the HTPB propellants with the same burning rate,compared with that of adding ammonium oxalate,the combustion residue of propellant containing BPE-1524CD reduces by 50%,and the specific impulse increases by 10~20 N·s/kg.Three kinds of quater-nary ammonium perchlorate are easily adsorbed on the surface of AP,and there is a positive correlation between the burning rates of HTPB propellants adding quaternary ammonium perchlorate and the thermal conductivity.