Self-assembly strengthening-toughening epoxy/Graphene composites through intermolecular π-π interactions with ultralow Graphene content

Abstract

Dispersion of Graphene (GE), high cost of massive usage of GE, and synergistic efficiency of GE and other fillers on epoxy resin (ER) are still challenges. This work not only achieves the uniform dispersion of few-layered GE through π-π interaction between GE and phenyl glycidyl ether (PGE), but also presents an equation in calculating the synergistic efficiency of multiple tougheners. The results show that the strength, modulus, elongation at break, and impact strength of ER can be simultaneously improved when D8 (an epoxy resin with side aliphatic chains) and PGE/GE are used together (D8/PG-X samples) or alone, and the D8/PG-X samples exhibit incomparable positive synergistic efficiency in both strength and toughness with ultralow GE content. The improvement of the impact strength, elongation at break, tensile modulus, and tensile strength in the optimum D8/PG-5 system is 115.5 %, 45.7 %, 17.8 %, and 28.3 % compared with unmodified ER system. We demonstrate that the improved comprehensive properties of the D8/PG-X samples as well as the improved interlaminar shear strength (ILSS) of the carbon fiber (CF)/ER composites can be ascribed to synergistic strengthening-toughening effect of self-assembly effect of aliphatic chains in D8 and uniformed dispersed GE (by π-π interaction). The impressive synergistic strengthening-toughening strategy can provide theoretical guidance for the preparation of high-performance ER with ultralow GE content.