5‐Aminoindole is designed for aldehyde‐functional benzoxazine (PHB‐a) copolymerization due to the special reaction between the indole and aldehyde groups, and the copolymerization with benzoxazine monomers. The curing and mechanical behavior and thermal properties of the cured resins are investigated using Fourier transform infrared spectroscopy, ¹H NMR spectroscopy, differential scanning calorimetry, scanning electron microscopy, dynamic mechanical analysis, tensile tests and thermogravimetric analysis. The resulting networks show better processability and mechanical properties without obvious degradation in thermal performance. The low curing temperature (70 °C) of PHB‐a is achieved after incorporation of 5‐aminoindole. An elongation rate of 2.54% and a forcing break of around 72.3 MPa are achieved, while neat poly(PHB‐a) is brittle and failed in the grips. Furthermore, its glass transition temperature is maintained up to 234 °C. These findings open a new way to realize low‐temperature curing and to improve the mechanical properties of brittle polybenzoxazine resins under the premise of maintaining good thermal stability. © 2020 Society of Industrial Chemistry

中文翻译：

---

5-氨基吲哚/苯并恶嗪共聚可提高醛官能聚苯并恶嗪的可加工性和机械性能

5-氨基吲哚由于吲哚和醛基之间的特殊反应以及与苯并恶嗪单体的共聚作用而设计用于醛官能的苯并恶嗪（PHB-a）共聚。使用傅立叶变换红外光谱法研究了固化树脂的固化，力学行为和热性能，¹1 H NMR光谱，差示扫描量热法，扫描电子显微镜，动态力学分析，拉伸试验和热重分析。所得的网络显示出更好的可加工性和机械性能，而热性能没有明显下降。加入5-氨基吲哚后，PHB-a的固化温度低（70°C）。达到2.54％的伸长率和72.3 MPa左右的强制断裂，而纯净的聚（PHB-a）则很脆并且在握持过程中失效。此外，其玻璃化转变温度维持在234°C。这些发现为在保持良好的热稳定性的前提下实现低温固化并改善脆性聚苯并恶嗪树脂的机械性能开辟了一条新途径。©2020工业化学学会