Hydroxyl-terminated polybutadiene (HTPB) adhesive has a low polarity main chain, resulting in poor compatibility with energetic components and a lack of energy-contributing groups, thus offering a limited energy contribution to propellants. Despite the diverse modification methods available for HTPB, they often suffer from harsh reaction conditions, decreased performance post-modification, and limited modification pathways. In this study, simple “one-pot polycondensation” was employed to synthesize a hyperbranched polyborate (HBPB) with a B–O–C backbone structure for the modification of HTPB-based adhesives. The modified HBPB/HTPB adhesive exhibited excellent mechanical properties at both room and low temperatures. Compared to pure HTPB, the tensile strength at room temperature increased by 198%, and at low temperatures, the increase reached 941%. Additionally, the adhesion strength improved by 214%, enhancing the adhesive bonding effect and reducing the occurrence of “debonding” issues. Moreover, HBPB's unique three-dimensional topological structure and flexible chains imparted better low-temperature adaptability to HTPB, lowering the glass transition temperature (T_g) by 16.03 °C. The numerous active terminal groups increased the crosslinking density, thereby enhancing the strength of the HTPB system and significantly improving the performance of the composite material. This study addresses the shortcomings of existing adhesives in terms of polarity and low-temperature adaptability, providing an effective technical pathway for the further development of adhesives for solid propellants.

中文翻译：

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超支化聚硼酸酯改性 HTPB 粘合剂，具有增强的性能和更低的玻璃化转变温度


端羟基聚丁二烯（HTPB）粘合剂的主链极性较低，导致与含能组分的相容性差，且缺乏供能基团，从而为推进剂提供的能量有限。尽管HTPB可用的修饰方法多种多样，但它们常常面临反应条件恶劣、修饰后性能下降和修饰途径有限的问题。在本研究中，采用简单的“一锅缩聚”来合成具有 B-O-C 主链结构的超支化聚硼酸酯 (HBPB)，用于对 HTPB 基粘合剂进行改性。改性HBPB/HTPB粘合剂在室温和低温下均表现出优异的机械性能。与纯HTPB相比，常温下拉伸强度提高了198%，低温下提高达到941%。此外，粘合强度提高了214%，增强了粘合效果并减少了“脱粘”问题的发生。此外，HBPB独特的三维拓扑结构和柔性链赋予HTPB更好的低温适应性，使玻璃化转变温度（ T _g ）降低16.03℃。众多的活性端基增加了交联密度，从而增强了HTPB体系的强度，显着改善了复合材料的性能。该研究解决了现有粘合剂在极性和低温适应性方面的缺点，为固体推进剂粘合剂的进一步发展提供了有效的技术途径。