Abstract In this study, synthesis of three hydroxyl-terminated block copolymers of varying molecular weight by ring opening polymerization of ԑ-caprolactone using hydroxyl-terminated poly butadiene as the initiator and stannous octoate as the catalyst was attempted. These block copolymers were specifically synthesized for its application in solid rocket propellants as an energetic binder. The desired chemical links between blocks were noticed in 1H nuclear magnetic resonance (NMR) and 13C NMR spectra, followed by confirmation in 1H/13C heteronuclear single quantum coherence and Fourier transform infrared spectra. To specify these block copolymers, various properties such as hydroxyl value (OH value), number average molecular weight ( M ¯ n ), specific gravity (ρ), rheological properties, glass transition temperature (Tg), thermal decomposition, and miscibility with nitrate ester plasticizers were determined. Additionally, the mechanical properties of the samples were evaluated using isocyanates as curators at NCO/OH equivalence ratio of 0.8 and 1.0. Finally, the best combination was selected based on physicochemical properties and miscibility with nitrate esters for further evaluation in composite propellant. We also theoretically studied the ballistic parameters of composite propellants by the NASA CEC-71 program to observe the gain of density impulse as the plasticizer to polymer ratio was increased.

中文翻译：

---

探索用于复合推进剂应用的聚丁二烯和ε-己内酯的遥爪嵌段共聚物

摘要 本研究以端羟基聚丁二烯为引发剂，辛酸亚锡为催化剂，通过环己内酯的开环聚合合成三种不同分子量的端羟基嵌段共聚物。这些嵌段共聚物是专门合成的，用于作为高能粘合剂在固体火箭推进剂中的应用。在 1H 核磁共振 (NMR) 和 13C NMR 光谱中注意到了嵌段之间所需的化学联系，随后在 1H/13C 异核单量子相干和傅里叶变换红外光谱中得到了确认。为了指定这些嵌段共聚物，各种特性，如羟基值（OH 值）、数均分子量（ M¯ n ）、比重（ρ）、流变特性、玻璃化转变温度（Tg）、热分解、并测定了与硝酸酯增塑剂的混溶性。此外，在 NCO/OH 当量比为 0.8 和 1.0 的情况下，使用异氰酸酯作为固化剂来评估样品的机械性能。最后，根据理化性质和与硝酸酯的混溶性选择最佳组合，以进一步评估复合推进剂。我们还通过 NASA CEC-71 计划从理论上研究了复合推进剂的弹道参数，以观察随着增塑剂与聚合物比率的增加，密度脉冲的增益。根据物理化学性质和与硝酸酯的混溶性选择最佳组合，以进一步评估复合推进剂。我们还通过 NASA CEC-71 计划从理论上研究了复合推进剂的弹道参数，以观察随着增塑剂与聚合物比率的增加，密度脉冲的增益。根据理化性质和与硝酸酯的混溶性选择最佳组合，以进一步评估复合推进剂。我们还通过 NASA CEC-71 计划从理论上研究了复合推进剂的弹道参数，以观察随着增塑剂与聚合物比率的增加，密度脉冲的增益。