A series of biobased benzoxazine oligomers suitable for vacuum-assisted resin transfer molding (RTM) were prepared from eugenol derivatives, furfurylamine, diamine, and paraformaldehyde. After the structures of these oligomers were identified by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (¹H NMR and ¹³C NMR), their curing behaviors and processability were evaluated by differential scanning calorimetry, FT-IR, and rheological tests. Results showed that the oligomers had stable viscosity lower than 1 Pa·s in the temperature range from 60 to 190 °C, and their processing window was found to be wider than 160 °C. The cured resins exhibited excellent thermal properties (10% thermal weight loss at 406 °C and glass transition temperature greater than 110 °C), good hydrophobic performance, and low moisture absorption. The benzoxazine oligomers reported here demonstrated great potential in the fabrication of composites, especially the green composites via more efficient processes, such as RTM.

中文翻译：

---

通过引入软硅链段合成适用于真空辅助树脂传递模塑工艺的生物基苯并恶嗪

由丁香酚衍生物，糠胺，二胺和多聚甲醛制备了一系列适用于真空辅助树脂传递模塑（RTM）的生物基苯并恶嗪低聚物。通过傅立叶变换红外光谱（FT-IR）和核磁共振光谱（¹ H NMR和¹³通过差示扫描量热法，傅立叶变换红外光谱和流变学测试，对它们的固化行为和可加工性进行了评估。结果表明，低聚物在60至190°C的温度范围内具有低于1 Pa·s的稳定粘度，并且发现其加工范围大于160°C。固化的树脂表现出出色的热性能（在406°C和玻璃化转变温度大于110°C时，热重量损失10％），良好的疏水性和低吸湿性。本文报道的苯并恶嗪低聚物在通过更有效的工艺（例如RTM）制造复合材料（尤其是绿色复合材料）方面显示出巨大的潜力。