Effect of EPD coated silanized graphene oxide on carbon fiber reinforced plastic: An emphasis on mechanical properties at cryogenic temperatures

Abstract

The space industry is constantly exploring lightweight, high-strength materials, particularly carbon fiber reinforced polymer (CFRP) composites. Nonetheless, in some cryogenic space applications, neat CFRP fails miserably. Here, silane functionalized graphene oxide (SGO) was coated on the carbon fiber surface to modify its properties. SGO is deposited onto a PAN-based plain weave carbon fiber using the electrophoretic deposition (EPD) process. SGO coated carbon fiber, along with epoxy resin, was used to fabricate CFRP laminates. From mechanical studies of CFRP samples, tensile, flexural, and impact strength improved by 13.1 %, 26.6 %, and 3.9 %, respectively, at room temperature (RT). The improvements were 15.1 %, 35.3 %, and 13.5 %, respectively, at cryogenic temperatures (CT). FTIR studies confirmed the emergence of a flexible Si-O-Si bond, which is a key factor for improved strength. AFM and SEM analysis were conducted to investigate contact roughness improvement. Contact angle microscopy examined SGO-induced wettability of modified carbon fiber. Also, a fracture study showed that the failure mode of SGO-coated CFRP at CT had changed from interface failure to matrix failure.