Wedge Test of Carbon-Nanotube-Reinforced Epoxy Adhesive Joints

摘要

Epoxy adhesives reinforced with carbon nanotubes (CNTs) were developed. The distribution of the CNTs in the epoxy matrix was observed with transmission electron microscopy. Joints were formed by unclad 2024-T3 aluminum adherents bonded with the CNT-filled epoxy adhesives. The durability of the joints was studied with a wedge test under water at 60 degrees C. The addition of CNTs to the epoxy greatly improved the adhesive joint durability. The initial craA length of the joint with 1 wt % CNTs, which was obtained before the wedge specimen was put into water, was only about 7% of that with neat epoxy. After immersion of the specimens in 60 degrees C water, the joint with neat epoxy failed after 3 h, but all of the joints adhered with different fractions of CNTs were still bound together after the experimental time of 90 h. The significant enhancement by CNTs of the adhesive joint durability was mainly attributed to the high mechanical properties of the CNTs and their ability to resist water. Nevertheless, the experimental results also reveal that the durability of the joints showed an optimum value at approximately I wt % CNTs, beyond which a decrease in the property was observed. In addition, the failure mechanism of the joints was also investigated in terms of interfacial failure and cohesive failure. Cohesive dominated failure was found for the joint bonded with I wt %. CNT-filled epoxy. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 2957-2962, 2009