Papers by Author: Xing Xiang Zhang

Abstract: Thenovel Polyaniline/viscose fiber have been synthesized in situ by oxidativepolymerization of aniline with ammonium persulfate as an oxidant and viscose fiberas a template. It was found that the PANI particlesdeposited on the surface of viscose fiberconnected to form acontinuous network by taking along the viscose fiber template,which increases the thermal stability and electrical conductivity of viscose fiber.This work provides a new field of potential applications of conducting polymer.

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: The phase change materials (PCMs) can absorb, store or release large latent heat over a defined temperature range while the materials change phase or state, so they can be potentially used in thermal energy storage. In this paper, a series of microencapsulated phase change materials (MicroPCMs) with n-octadecane and n-dodecanol as core were successfully fabricated respectively, where the styrene-based copolymer, acrylic based copolymer, melamine-formaldehyde resin and polyurea were selected as shell materials. The morphology of these MicroPCMs was observed by scanning electron microscopy (SEM), and the core-shell structure and the shell thickness of microcapsules were also characterized by SEM. In addition, the phase change properties of MicroPCMs were investigated using differential scanning calorimetry (DSC) analysis. Furthermore, thermal-regulated calcium alginate fiber was produced by adding MicroPCMs in wet-spinning process; and the effects of various types of MicroPCMs on fiber was discussed.

Abstract: Octadecylated poly (vinyl alcohol) (PVA-C18) comb-like polymer was prepared through the reaction between PVA and 1-bromooctadecane via O-alkylation method. The structure, thermal properties and packing mode of PVA-C18 comb-like polymer were detailed investigated with Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), and X-ray diffraction (XRD). The results show that octadecyl side chains had been successfully grafted onto PVA backbones, and PVA-C18 comb-like polymer exhibit the better thermal storage properties with enthalpy of 29.3kJ/mol , indicated that it is one kind of solid-solid phase change materials.

Abstract: Microencapsulated n-octadecane (MicroC18) and doped with thermochromatic powders (TC-MicroC18) were prepared with melamine-formaldehyde (M-F) resin as the wall via in-situ polymerization. The chemical structure and thermal behavior of microcapsules were investigated using fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Experimental results show that 63 wt% n-C18 has been incorporated into microcapsules, and the obvious thermochromatic effect of TC-MicroC18 is displayed with temperature changing. The structure-properties of TC-MicroC18 also is discussed in detail from the aspect of molecular structure.

Abstract: A series of N-octadecylated polyethyleneimine (PEI18C) comblike polymers with different grafting ratios, through N-alkylation method, have been successfully prepared. The chemical structure and thermal behavior of PEI18C comblike polymers with different grafting ratios has been characterized by Fourier transformed infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Experimental shows that C18 alkyl groups have been successfully grafted onto PEI backbones, and the thermal behavior of PEI18C comblike polymers with different grafting ratios exhibit the linear increment with the grafting ratio of alkyl groups. It can be attributed to the effect of the grafting density of alkyl side groups along PEI backbones. The detailed investigation and discussion is carried out from the viewpoint of side chain crystallization and molecular packing behaviors.

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.

Abstract: Pristine multi-walled carbon nanotubes (P-MWNTs) were functionalized with 4-substituted benzoic acid via ‘‘direct’’ Friedel-Crafts acylation in mild reaction medium of polyphosphoric acid (PPA)/phosphorous pentoxide (P2O5). Raman spectroscopy, thermogravimetric analysis, transmission electron microscopy were applied in this paper to demonstrate that multi-walled carbon nanotubes inherently have functional groups on their surfaces as a result of the reaction. The overall evidence indicates that the 4-substituted benzoic acid functionalization of carbon nanotube can be achieved without oxidation as pre-treatment. Thus, aryl carbonyl moieties with different length of 4-substituted alkyl acyl amine functionalized MWNTs（F-MWNTs） can be synthesized simply, without disrupting the primary structures of the nanotubes.