• Louro, Cs
• Amaro, Am
• Rodrigues, João
• Bernardo, L.
• Pinto, Dg
• Lopes, S.

Abstract

Reinforced concrete is widely used in structures. New materials to replace both the steel and the concrete have been studied in many research centres. One of the possibilities for the reinforcement is the partial or total replacement of the steel bars by new composite materials. Nano composites are very promising, and an investigation line was developed to this end by an interdisciplinary team. On this work, the mechanical properties of epoxy resin nanocomposites (EPNCs) filled with alpha-Al2O3 nanoparticles (NPs) with irregular shape and approximately 100 nm maximum diameter size was investigated. The variable study was the alumina NPs contents: 1,3 and 5 wt.%. The NPs were previously pretreated with a silane agent (APTES). Two hardeners, 3-dodec-2-enyloxolane-2,5-dione (DDSA) and 8-methyl-3a,4,7,7a-tetrahydro-4,7-methano-2-benzofuran-1,3-dione (MNA), frequently used in epoxy resin embedding tissues, were used simultaneously for this study. Unlike other hardeners, DDSA does not need curing treatment, constituting a novel application and a saving time-energy during the manufacturing process. Considering the mechanical behaviour, it was observed that the EPNCs filled with 5 wt.% of alumina NPs showed the maximum improvement in flexural modulus, around 14 % when compared to the pristine EP sample. No relevant effect was observed on the flexural strength by adding alumina NPs. Additionally, the maximum increase observed for hardness, and Young's modulus were about 13 % and 28 %, respectively (the maximum increase was observed at 3 wt.%).

Topics

• nanoparticle
• nanocomposite
• impedance spectroscopy
• strength
• steel
• flexural strength
• hardness
• resin
• curing
• atom probe tomography