title: Influence of atmospheric plasma on physicochemical properties of vapor-grown graphite nanofibers.
abstract: Vapor-grown graphite nanofibers (GNFs) were modified by plasma treatments using low-pressure plasmas with different gases (Ar gas only and/or Ar/O2 gases), flow rates, pressures, and powers. Surface characterizations and morphologies of the GNFs after plasma treatment were investigated by X-ray photoelectron spectroscopy (XPS), contact angle, titration, and transmission electron microscopy (TEM) measurements. Also, the investigation of thermomechanical behavior and impact strengths of the GNFs/epoxy composites was performed by dynamic-mechanical thermal analysis (DMTA) and Izod impact testing, respectively. The plasma treatment of the fibers changed the surface morphologies by forming a layer with a thickness on the order of 1 nm, mainly consisting of oxygen functional groups such as hydroxyl, carbonyl, and carboxyl groups. After functionalization of the complete surfaces, further plasma treatment did not enhance the superficial oxygen content but slightly changed the portions of the functional groups. Also, the composites with plasma-treated GNFs showed an increase in T(g) and impact strength compared to the composites containing the same amount of plasma-untreated GNFs.
authors.affiliation: Advanced Materials Division, Korea Research Institute of Chemical Technology, P.O. Box 107, Yusong, Daejeon 305-600, South Korea.
authors.forename: Min-Kang
authors.initials: MK
authors.lastname: Seo
authors.forename: Soo-Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Sang-Kwan
authors.initials: SK
authors.lastname: Lee
mesh_terms: D001272:Atmosphere; D006108:Graphite / Q000737:chemistry*; D008854:Microscopy, Electron; D049329:Nanostructures / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics; D014835:Volatilization
chemical_list: D006108:Graphite