ABSTRACT
This chapter discusses the advantages and disadvantages of hybrid composites nano-modied by carbon nanostructures. A brief review on carbon nanotubes and graphene describes the major techniques employed into the “composite’s world.” To be able to exemplify the graphene use, this chapter reports the effect of graphene dispersion into epoxy adhesives and its aging by UVA light exposure. To achieve this goal, two approaches were employed. The rst one was direct exposure of the nano-modied AR300/AH30-150 samples to UVA light for 400 hours. After the aging process, nanoindentation tests were performed. The second approach was based on tensile tests of aged single lap joints (SLJs). The graphene nanostructures formed inside the AR300/AH30-150 nano-modied adhesive seems to block the aging process, as none of the specimens presented a decrease on stiffness. The force-displacement curves obtained by nanoindentation seem to indicate a good dispersion process, as the large majority of the curves laid down at the same path. When the SLJs were tested, the results also indicated an average increase on bearing-load capacity of 40.96% and 72.03% for 1 wt.% and 2 wt.%, respectively for 100 hours aging. When the aging reached 200 hours, there is a decrease on load capacity when compared against the 100 hours results. The average load capacity was 27.03% and 58.19% higher than the not aged AR300/AH30-150 SLJs. At 400 hours, there is another increase on load capacity, that is, 32.06% and 74.43% for 1 wt.% and 2 wt.% graphene, respectively. A nite element simulation revealed that peel and shear stresses at adhesive edge increased by 82%. The Fourier Transformed Infrared tests revealed that chemical changes on hydroxyl, carbonyl, and epoxy components could be the reason for this behavior. The graphene dispersion into the epoxy adhesives seems to have a double folded effect; in one hand, it increases the bonded joint capacity, and on the other hand, blocks the aging effect of UVA light.
