The effect of surface treatment on graphite nanoplatelets used in fiber reinforced composites

Abstract

Atmospheric plasma treatment (APT) was used to surface-activate graphite nanoplatelets (GnP) as well as highly graphitic P100 fibers used to manufacture composites. X-ray photoelectron spectroscopy showed an increase in the O=C ratio of the treated surfaces when using either CO or O 2 as the active gas, whereas CO exhibited less damage to the treated reinforcement carbon material. APT of P100 fibers resulted in a 75% increase in composite tensile strength when compared to composites using untreated fibers. Surface treatment of GnPs also resulted in GnP=epoxy composites with significantly higher glass transition temperatures (Tg's) and 50% higher flexural strengths than those with no surface treatment because of stronger particle-to-resin coupling, which was also evidenced by the fracture surfaces. The effect of GnP loading concentration and plasma treatment duration was also evaluated on the tensile strength of fiber-reinforced composites. The addition of untreated GnP filler resulted in a decrease in strength up to the 1% loading. However, higher loading conditions resulted in a 20% improvement because of GnP orientation effects. Fracture surfaces suggest that the fibers provided a mechanism for the GnPs to orient themselves parallel to the fiber axis, developing an oriented matrix microstructure that contributes to added crack deflection. Incorporating surface-treated GnPs in these composites resulted in tensile strengths that were as high as 50% stronger than the untreated systems for all loading conditions. Increased GnP-to-matrix bonding as well as enhanced orientation of the GnPs resulted in multifunctional composites with improved mechanical performance.

The Role of Functionalization in the Applications of Carbon Materials: An Overview

“…The authors of [344] describe a plasma treatment by air dielectric barrier discharge (DBD) at atmospheric pressure to treat the surface of CNFs to induce COOH, -C-OH and =C=O groups leading to a higher reactivity between fiber surface and matrix and a higher surface roughness. Atmospheric CO 2 and O 2 plasma treatments were used to activate graphite nanoplatelets as well as highly graphitic fibers used as reinforcing elements in composites [345]. The plasma treatments induced an increase of the oxygen functionalities on the treated surfaces.…”

Plasma-graft anhydride on Carbon Fiber and its Effect on Composite Properties

“…The SFC test method, originally developed from the early work of Kelly and Tyson [13], can provide abundant statistical information, such as interfacial failure modes and interfacial shear strength (IFSS) value, using only a few specimens [14]. Each test specimen for the fragmentation test consists of a single carbon fiber embedded in a matrix along the tensile loading direction.…”

Incorporation of silicon dioxide nanoparticles at the carbon fiber‐epoxy matrix interphase and its effect on composite mechanical properties

“…Recently, the incorporation of nanoparticles at the surface of the fibers or into the sizing such as carbon nanotubes and graphene nanoplatelets has been investigated . Adding nanoparticles in the sizing shows advantages in comparison to mixing of the particles directly in the matrix, because those particles can lead to a very sharp increase of the viscosity, generating difficulties for composite processing.…”