Tensile properties of graphene nanoplatelets/epoxy composites fabricated by various dispersion techniques

• Published in: Polymer testing Vol. 76; pp. 181 - 191
• Main Authors: Kilic, Ugur, Sherif, Muhammad M., Ozbulut, Osman E.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-07-2019
• Subjects: Dispersion techniques; Epoxy composites; GNP; Graphene nanoplatelets; GNP; Epoxy composites; Graphene nanoplatelets; Dispersion techniques
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/j.polymertesting.2019.03.028

This study investigates the tensile behavior of ductile and brittle epoxy polymers reinforced by graphene nanoplatelets (GNPs) dispersed by various methodologies. Dispersion of GNPs into the epoxy matrix using sonication or sonication in combination with high shear mixing was investigated. Also, the effectiveness of the dispersion of GNPs into epoxy resin or hardener was assessed. Then, the effect of GNP concentration on the tensile properties of GNP/epoxy composites fabricated by three selected dispersion techniques was explored. A large number of specimens were tested under uniaxial tensile loading and the results were analyzed in terms of tensile strength, fracture elongation, and tensile modulus. Finally, scanning electron microscopy imaging was used to assess the fractured surface of the selected specimens. Results indicate that the addition of GNPs into brittle epoxy does not provide significant improvements in tensile properties. On the other hand, up to 41% increase in tensile strength and 19% increase in tensile modulus were observed for ductile epoxy with 1 wt% GNPs. However, the addition of GNPs into either brittle or ductile epoxy reduces the fracture elongation of the developed composites.
•Effective dispersion of GNPs into a brittle and a ductile epoxy polymer using sonication and high shear mixing was explored.•The effect of GNP concentration on tensile properties of epoxy nanocomposites was investigated.•Dispersing GNPs into epoxy resin first 30 min sonication and then 60 min shear mixing provided better results.•Using only sonication for the dispersion of GNPs leads considerable decreases in fracture elongation.•The use of 1 wt% of GNP in ductile epoxy increases the tensile strength by 41% and tensile modulus by 19%.