Papers by Author: Yong Tan

Abstract: A novel approach to the functionalization of nanometer-sized graphene was presented in this work. Covalent bonding between the filler and matrix was formed, with minimal disruption to the sp² hybridization of the pristine graphene sheet. Functionalization proceeded by covalently bonding a 4-substituted benzoic acid monomer to the surface of expanded graphene, via ‘‘direct Friedel-Crafts” acylation in mild reaction medium of polyphosphoric acid (PPA)/phosphorous pentoxide. Polyamide 6 (PA6)-functionalized graphene (FG) composites were prepared by in situ polymerization of ε-caprolactam in the presence of nanometer-sized FG. Nanocomposite fiber with 0.1 wt.% content of nanometer-sized FG was prepared with a piston spinning machine and hot-roller drawing machine. The nanometer-sized FG performed homogeneous dispersion in the polymer matrix. The mechanical properties of the PA6-FG composites fiber was enhanced by adding FG in the polymer matrix. The new functionalization method paves the way to prepare graphene-based nanocomposites fiber simply, without disrupting the primary structures of nanometer-sized graphene.

Abstract: Pristine polyacrylonitrile (PAN)-base carbon fibers (P-CFs) was functionalized with 4-Aminobenzoic acid via ‘‘direct’’ Friedel-Crafts acylation in a mild reaction medium of polyphosphoric acid (PPA)/phosphorous pentoxid (P2O5). Fourier transform infrared spectroscopy, Raman spectroscopy, Scanning electron microscopy were applied in this study to demonstrate that PAN-base carbon fibers inherently have functional groups on their surface as a result of the reaction. The overall evidence indicates that the 4-Aminobenzoic acid functionalization of carbon fibers can be achieved without oxidation as pre-treatment. Thus, amine functionalized CFs（F-CFs）can be synthesized, without disrupting the strength of the carbon fibers.