Abstract Nano-silica modified phenolic resin film is prepared using different mass fractions of nano-silica by liquid composites molding (LCM). The effects of nano-silica on the rheology and curing of phenolic resin are studied by rheometer and differential scanning calorimeter (DSC). The results show that the viscosity of nano-silica modified phenolic resin decreases with the increase of temperature, and the viscosity is lowest between 70°C and 90°C. The appropriate resin film infusion (RFI) process is investigated, and the stepped curing process system is established. In addition, the microstructures of modified phenolic film and composites are tested by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Nano-silica can be uniformly dispersed in phenolic resin when the amount of nano-silica added is ≤ 4%. And the mechanical properties of nano-silica modified phenolic composites are tested by universal material testing machine. The optimum nano-silica mass loading for the improvement of mechanical properties is found. This work provides an effective way to prepare the modified phenolic resin film suitable for resin film infusion (RFI) processes, and it maybe become a backbone of thermal protection material in aerospace.

中文翻译：

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纳米二氧化硅改性酚醛树脂薄膜：制造与性能

摘要 以不同质量分数的纳米二氧化硅为原料，采用液相复合成型法制备了纳米二氧化硅改性酚醛树脂薄膜。采用流变仪和差示扫描量热仪(DSC)研究了纳米二氧化硅对酚醛树脂流变学和固化的影响。结果表明，纳米二氧化硅改性酚醛树脂的粘度随温度升高而降低，70～90℃时粘度最低。研究了合适的树脂薄膜灌注（RFI）工艺，建立了阶梯固化工艺体系。此外，通过扫描电子显微镜（SEM）和能量色散光谱（EDS）测试了改性酚醛薄膜和复合材料的微观结构。当纳米二氧化硅的加入量≤4%时，纳米二氧化硅可以均匀地分散在酚醛树脂中。并通过万能材料试验机测试纳米二氧化硅改性酚醛复合材料的力学性能。找到了用于改善机械性能的最佳纳米二氧化硅质量负载。该工作为制备适用于树脂薄膜灌注（RFI）工艺的改性酚醛树脂薄膜提供了一种有效途径，有望成为航空航天热防护材料的支柱。