Banerjee Poulami, Parasuram Sampath, Kumar S, Bose Suryasarathi
Department of Materials Engineering, Indian Institute of Science, Bangalore - 560012, India.
Nanoscale. 2022 Jun 30;14(25):9004-9020. doi: 10.1039/d2nr01234k.
Carbon fiber reinforced epoxy (CFRE) laminate structures have emerged as futuristic materials having surpassed metals in strength and durability. The interfacial chemistry determines the mechanical performance of such laminates. In this study, a unique approach was adopted wherein the alternate layers of the carbon fiber (CF) mat were grown with ZnO nano-rods and modified with bis-maleimide (BMI), and epoxy resin containing 0.2 or 0.5 wt% graphene oxide (GO) was infused using conventional VARTM technology to enhance the mechanical interlocking of epoxy with the fiber as well as to impart self-healing properties to the laminate. While ZnO rods offer surface roughness thereby facilitating better wetting of epoxy, the Diels-Alder thermo-reversible bonds between BMI and GO facilitate self-healing properties besides improving the interfacial adhesion between epoxy and CF. The rationale behind this work is to synergistically improve the interface-dominated mechanical properties like interlaminar shear strength (ILSS) while maintaining or even improving fiber-dominated properties like flexural strength (FS) as well as imparting considerable recovery in strength post the self-healing cycle. The laminates after this treatment (having 0.5 wt% GO) indeed exhibited 46% improvement in FS and 33% improvement in ILSS properties as well as an ILSS recovery of 70%. The surface analysis suggests that ZnO nano-rods offer surface roughness that helps in the wettability of the matrix on the fibers. In addition, the 2D and 3D representative volume analysis (RVE) model was established to identify the load transfer behaviour in the ZnO-CF-epoxy interface in the microscale reference region. The fractographic analysis confirmed that rigid ZnO nano-rods allowed better matrix adhesion resulting in improved mechanical performance.
碳纤维增强环氧树脂（CFRE）层压结构已成为具有未来感的材料，其强度和耐久性超过了金属。界面化学决定了此类层压板的机械性能。在本研究中，采用了一种独特的方法，即碳纤维（CF）毡的交替层生长有ZnO纳米棒并用双马来酰亚胺（BMI）进行改性，然后使用传统的真空辅助树脂传递模塑（VARTM）技术注入含有0.2或0.5 wt%氧化石墨烯（GO）的环氧树脂，以增强环氧树脂与纤维之间的机械互锁，并赋予层压板自愈合性能。虽然ZnO棒提供了表面粗糙度，从而促进了环氧树脂的更好润湿，但BMI和GO之间的狄尔斯-阿尔德热可逆键除了改善环氧树脂与CF之间的界面粘附外，还促进了自愈合性能。这项工作背后的基本原理是协同改善界面主导的机械性能，如层间剪切强度（ILSS），同时保持甚至改善纤维主导的性能，如弯曲强度（FS），并在自愈合循环后使强度有相当大的恢复。经过这种处理的层压板（含有0.5 wt%的GO）确实在FS方面提高了46%，在ILSS性能方面提高了33%，并且ILSS恢复率达到了70%。表面分析表明，ZnO纳米棒提供的表面粗糙度有助于基体在纤维上的润湿性。此外，还建立了二维和三维代表性体积分析（RVE）模型，以确定微观参考区域中ZnO-CF-环氧树脂界面的载荷传递行为。断口分析证实，刚性的ZnO纳米棒使基体具有更好的粘附性，从而提高了机械性能。
