The improvement of mechanical properties and toughness of nanoparticles for epoxy composites was mostly dependent on the disperse state of nanoparticles in epoxy matrices. When the content of nanoparticles was higher than a threshold value, it was easy to aggregate and then affect the improvement effect. Pickering emulsion was prepared using SiO₂ nanoparticles as emulsifier and functional monomer as oil phase. The influence of Pickering emulsion on the curing process was investigated. The effect of Pickering emulsion on the mechanical properties, toughness, and glass transition temperature (Tg) was studied. Impact and tensile fracture surface were observed by scanning electron microscopy (SEM). Results from differential scanning calorimeter (DSC), tensile, impact, and fracture toughness tests are provided. The results indicated that the introduction of Pickering emulsion can eliminate the residual stress and accelerate curing reaction. Epoxy composites were capable of increasing tensile strength by up to 29.9%, impact strength of three‐fold, fracture toughness of 35%, and Tg of 20.7°C in comparison with the reference sample. SEM images showed that SiO₂ nanoparticles exhibit a good dispersion in epoxy matrix. The increases in mechanical properties, toughness, and Tg of epoxy composites were attributed to the “Second Phase Toughness” mechanism.

中文翻译：

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皮克林乳液对环氧复合材料力学性能和断裂韧性的影响。

用于环氧树脂复合材料的纳米粒子的机械性能和韧性的提高主要取决于纳米粒子在环氧树脂基体中的分散状态。当纳米颗粒的含量高于阈值时，其易于聚集并随后影响改善效果。使用SiO ₂制备Pickering乳液纳米粒子作为乳化剂，功能性单体作为油相。研究了Pickering乳液对固化过程的影响。研究了Pickering乳液对机械性能，韧性和玻璃化转变温度（Tg）的影响。通过扫描电子显微镜（SEM）观察冲击和拉伸断裂表面。提供了差示扫描量热仪（DSC），拉伸，冲击和断裂韧性测试的结果。结果表明，Pickering乳液的引入可以消除残余应力并加速固化反应。与参考样品相比，环氧树脂复合材料能够将拉伸强度提高29.9％，冲击强度提高三倍，断裂韧性提高35％，Tg达到20.7°C。SEM图像表明SiO ₂纳米颗粒在环氧基质中表现出良好的分散性。环氧复合材料的机械性能，韧性和Tg的提高归因于“第二相韧性”机制。