To provide high‐temperature polyimide matrix resins, novel carborane‐containing thermosetting polyimides are presented. First, the low‐viscosity carborane‐containing imide oligomers are synthesized using newly designed 1‐(3‐amino‐4‐tolyl)‐2‐(4‐aminophenyl)‐o‐carborane and aromatic dianhydride as monomers, 4‐phenylethynyl phthalic anhydride as the end‐capping reagent. Followed by thermal curing, the resulting polyimides show high T_g (≥500 °C) and above 92.1% char yield at 800 °C both in nitrogen and air atmosphere due to the incorporation of the bulky carborane cages. Aging studies, performed at 400 and 500 °C for 5 h in air on a carborane‐containing polyimide and a carborane‐free polyimide, show that the polyimide with carborane groups possesses excellent thermo‐oxidative stability. Moreover, the novel polyimides exhibit constant and relatively low coefficient of thermal expansion values over a wide range of temperature, indicative of a remarkable dimensional stability. Thus, this study clearly demonstrates the viability of the incorporation of carborane cages to access polyimide thermosets with ultrahigh T_g and thermo‐oxidative stability.

中文翻译：

---

衍生自含硼烷的二胺的高Tg和热氧化稳定的热固性聚酰亚胺

为了提供高温聚酰亚胺基体树脂，提出了新型的含碳硼烷的热固性聚酰亚胺。首先，使用新设计的1-（3-氨基-4-甲苯基）-2-（4-氨基苯基）-邻-甲硼烷和芳族二酐作为单体，4-苯基乙炔基邻苯二甲酸酐合成低粘度含硼烷的酰亚胺低聚物作为封端试剂。热固化后，所得的聚酰亚胺显示出较高的T _g（≥500°C）和氮气和空气中800°C时焦炭收率达到92.1％以上，这是由于引入了笨重的碳硼烷笼。在含碳硼烷的聚酰亚胺和无碳硼烷的聚酰亚胺中，在空气中于400和500°C下进行了5小时的老化研究，结果表明，具有碳硼烷基团的聚酰亚胺具有出色的热氧化稳定性。此外，新型聚酰亚胺在很宽的温度范围内显示出恒定且相对较低的热膨胀系数值，这表明尺寸稳定性非常好。因此，这项研究清楚地证明了结合碳硼烷笼子进入具有超高T _g和热氧化稳定性的聚酰亚胺热固性塑料的可行性。