Papers by Author: Hai Hui Liu

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: In this study, a 85/15 AN/MA copolymer (acrylonitrile – methylacrylate copolymer with feed ratio of 85/15 mol%) was synthesized by emulsion polymerization at 60 °C, and then the copolymer was used to produce hollow fiber (abbreviated as PAN hollow fiber )by melt spinning using a single screw extruder machine. The PAN hollow fiber was characterized by using Scanning Electron Microscope (SEM), Thermo-gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The hollow fiber of melt-spinning PAN with high hollow rate of 51.1% has a homogeneous wall and regular section. The hollow fiber is potentially used as raw materials to fabricate heat preservation fabric for comfort clothing.