Excellent overall performance of graphene/epoxy coatings prepared by covalent-noncovalent bridging modification of quinacridone

Abstract

In this work, we have successfully dispersed raw graphene into an epoxy coating by a facile solution mixing method using pristine and modified quinacridone as dispersants. Through mechanical and electrochemical property tests, we found that the overall performance of the graphene/epoxy coatings prepared by combining unmodified as well as modified quinacridone was significantly better than that of the coatings prepared by using only one form of the dispersant. The epoxy coatings prepared using 0.2 wt% graphene, 0.5 wt% unmodified quinacridone, and 0.5 wt% modified quinacridone showed excellent corrosion resistance, with the impedance modulus value remaining above 1010 Ω-cm2 even after 100 days of immersion in a 3.5 wt% NaCl solution at pH = 1. The coating also exhibited excellent mechanical properties, with a tensile strength of 20.88 MPa, which is 3.7 times higher than that of the pure epoxy coating, in addition to excellent abrasion resistance and pencil hardness up to 6H. This method provides a new strategy for the preparation of high-performance graphene reinforced organic coatings.