The high brittleness of epoxy resin at cryogenic temperature restricts their wide application in cryogenic engineering. In this study, polyhedral oligomeric silsesquioxane (POSS) with -Si-O-Si- molecular chains were synthesized, and the mechanical properties of diglycidyl ether of bisphenol A (E51 epoxy resin) were significantly enhanced at room temperature (RT) by incorporating a 4% POSS and curing agent 4,4′-diamino-diphenylmethane (DDM) as the E51/POSS/DDM resin system. Subsequently, by adding different contents of epoxidation hydroxyl-terminated polybutadiene (EHTPB) into the E51/POSS/DDM resin system, the EHTPB-E51/POSS/DDM resin system was prepared. The investigation into the impact of EHTPB content on the mechanical properties of EHTPB-E51/POSS/DDM resin system at room temperature (RT) revealed that EHTPB-E51/POSS/DDM resin system with 10% EHTPB exhibited the most favorable results. Specifically, the elongation at break, flexural strength, and critical stress intensity factor (K) were measured to be 6.82%, 143.75 MPa, and 1.83 MPa m, respectively. These values demonstrated a notable improvement of 53.3%, 26.9%, and 86.7% compared to those for the E51/DDM resin system. Concurrently, at 77 K, the elongation at break and critical stress intensity factor (K) increased by 37.8% and 73.5%, respectively. The toughening mechanism of the prepared EHTPB-E51/POSS/DDM resin system was further explored through resin-curing cross-linking simulation networks and SEM images of the fracture surface of resin samples. The study of EHTPB and POSS synergistically toughened epoxy resin provided a new efficient method to prepare epoxy resins with high toughness at low temperatures.

中文翻译：

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用于低温应用的 POSS/EHTPB 协同增韧环氧树脂

环氧树脂在低温下的高脆性限制了其在低温工程中的广泛应用。在这项研究中，合成了具有-Si-O-Si-分子链的多面体低聚倍半硅氧烷（POSS），并通过掺入一种有机硅，显着增强了双酚A二缩水甘油醚（E51环氧树脂）在室温（RT）下的机械性能。 4% POSS 和固化剂 4,4'-二氨基二苯甲烷 (DDM) 作为 E51/POSS/DDM 树脂体系。随后，通过在E51/POSS/DDM树脂体系中添加不同含量的环氧化端羟基聚丁二烯(EHTPB)，制备了EHTPB-E51/POSS/DDM树脂体系。室温（RT）下EHTPB含量对EHTPB-E51/POSS/DDM树脂体系机械性能影响的研究表明，含有10% EHTPB的EHTPB-E51/POSS/DDM树脂体系表现出最有利的结果。具体而言，测得断裂伸长率、弯曲强度和临界应力强度因子（K）分别为6.82%、143.75 MPa和1.83 MPa·m。与 E51/DDM 树脂体系相比，这些值显着提高了 53.3%、26.9% 和 86.7%。同时，在 77 K 时，断裂伸长率和临界应力强度因子 (K) 分别增加了 37.8% 和 73.5%。通过树脂固化交联模拟网络和树脂样品断裂表面的SEM图像，进一步探讨了所制备的EHTPB-E51/POSS/DDM树脂体系的增韧机理。 EHTPB与POSS协同增韧环氧树脂的研究为制备低温高韧性环氧树脂提供了一种新的有效方法。