To improve the low-temperature toughness of epoxy resins, in this study, an epoxy-terminated hyperbranched polysiloxane (EPTS-12) was synthesized and introduced into the epoxy resin as a toughener. The structure of EPTS-12 was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (¹H NMR), and the fractured surfaces of the modified resins were observed by a scanning electron microscope (SEM). With the content of EPTS-12 at 5 wt%, under room temperature (RT) and − 72 °C, the maximum values of elongation at break were 14.19% and 16.06%, increasing by 35.66% and 74.19% respectively. The test results of dynamic mechanical analysis (DMA) also showed that the toughness of the modified epoxy resins was improved. The SEM images of the fractured surfaces of the modified resins were used to investigate the toughening mechanism of the toughener (EPTS-12). With the virtue of a simple synthesis process, low cost, and good reproducibility, this toughener can further expand the application of epoxy resins.

为了提高环氧树脂的低温韧性，本研究合成了端环氧基超支化聚硅氧烷（EPTS-12），并将其作为增韧剂引入到环氧树脂中。采用傅里叶变换红外光谱（FT-IR）和核磁共振（¹ H NMR）对EPTS-12的结构进行表征，并通过扫描电子显微镜（SEM）观察改​​性树脂的断口表面。当EPTS-12含量为5wt%时，室温和-72℃下，断裂伸长率最大值分别为14.19%和16.06%，分别增加了35.66%和74.19%。动态力学分析（DMA）测试结果也表明，改性环氧树脂的韧性有所提高。利用改性树脂断裂面的SEM图像研究增韧剂(EPTS-12)的增韧机理。该增韧剂合成工艺简单、成本低、重现性好，可进一步拓展环氧树脂的应用。