Qian Dan, Zhou Jiahai, Zheng Jieyuan, Cao Jun, Wan Jintao, Fan Hong
State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
Zhejiang Chuanhua Chemical Group Co., Ltd., Hangzhou 311200, China.
Polymers (Basel). 2022 Oct 18;14(20):4391. doi: 10.3390/polym14204391.
Tremendous effort has been focused on improving the toughness of epoxy, but the common approaches diminish the mechanical properties. In this work, a new silicone-modified trifunctional epoxy monomer SITEUP is synthesized from the hydrosilylation transformation of eugenol epoxy (EPEU) and tris-(dimethylsiloxy)phenylsilane. The chemical structures and curing kinetics of SITEUP are investigated based on H-NMR, C-NMR, MADLI-TOF-MS, and DSC analyses. SITEUP is introduced into DGEBA/IPDA systems as a functional modifier in varied loadings for toughening the resulting epoxy thermosets. The impact strength of the modified epoxy thermosets containing 20% SITEUP is 84% higher than that of the pristine epoxy thermoset and also maintains high flexural strength. Further morphology study reveals that the plastic deformation caused by siloxane segments is the key factor accounting for the enhanced toughness of the finalized epoxy thermosets. Si-O-Si segments incorporated into the thermosetting network could absorb more energy by increasing the mobility of polymer chains under external stress and led to improved thermal stability and damping characteristics. In addition, SITEUP is able to decrease the surface tension and increase the hydrophobic properties of the resultant epoxy materials.
人们付出了巨大努力来提高环氧树脂的韧性，但常用方法会降低其机械性能。在这项工作中，通过丁香酚环氧树脂（EPEU）与三（二甲基硅氧基）苯基硅烷的硅氢加成转化反应，合成了一种新型有机硅改性三官能环氧单体SITEUP。基于氢核磁共振（H-NMR）、碳核磁共振（C-NMR）、基质辅助激光解吸电离飞行时间质谱（MADLI-TOF-MS）和差示扫描量热法（DSC）分析，研究了SITEUP的化学结构和固化动力学。将SITEUP作为功能改性剂以不同含量引入到二缩水甘油醚双酚A/异佛尔酮二胺（DGEBA/IPDA）体系中，以增韧所得的环氧热固性材料。含有20% SITEUP的改性环氧热固性材料的冲击强度比原始环氧热固性材料高84%，并且还保持了较高的弯曲强度。进一步的形态学研究表明，硅氧烷链段引起的塑性变形是最终环氧热固性材料韧性增强的关键因素。并入热固性网络中的硅氧硅链段可以通过在外部应力下增加聚合物链的流动性来吸收更多能量，并导致热稳定性和阻尼特性得到改善。此外，SITEUP能够降低所得环氧材料的表面张力并增加其疏水性。
