Functional Graphite Research Articles

Hierarchical Polyaniline Core-Shell Nanocomposites Coated on Modified Graphite for Improved Electrical Conductivity Performance.

Graphite has recently gained scientific and industrial attention due to its high electrical conductivity. In the current endeavor, a new way to fabricate novel and multifunctional nanocomposites using functional graphite (FG) as filler is presented. The fabrication of multilayered conducting composites of PANi/PMMA/PPG-b-PEG-b-PPG was carried out via in situ polymerization, using polyaniline (PANi), poly(methyl methacrylate) (PMMA) and block copolymer as matrices in the presence of FGfiller. The growth of PANi chains is manifested by PMMA due to the formation of H-bonding between imine and carbonyl groups of PANi and MMA units, respectively, and are responsible for ion exchange sites. FTIR spectroscopy was used for structural elucidation of composites while elemental analysis was accomplished by XPS and EDX spectroscopy. The morphology of the prepared PANi/PMMA/PPG-b-PEG-b-PPG@FG composites was inspected by the SEM. The structure and crystallinity of the composites was investigated via XRD. The improved thermal stability and properties of the nanocomposites were observed using TGA and DSC. The conductivity measurements were used to characterize the electrical conductivity performance of the resulting composites. The presence of functional filler as well as polyaniline shows a significant contribution towards the enhancement of electrical conductivity of PANi/PMMA/PPG-b-PEG-b-PPG@FG nanocomposites.

Functionalization and Chemical Linking of Reduced Graphene Oxide or Graphite onto Polyurethane and the Impact on the Tensile Strength and Sheet Resistance of Polymer Composites

Reduced graphene oxide (RGO) or graphite is functionalized with hydroxyl groups for linking to the sides of polyurethane (PU) chains. Blended PU with RGO or graphite is prepared as a control for comparison. The PU composites are compared with respect to their spectroscopic, thermal, mechanical, shape memory, and sheet resistance properties. Scanning electron microscopy images demonstrate the good distribution of functionalized graphene oxide (FGO) or functionalized graphite (FG) particles on the inner surface of the PU. The linking of FGO or FG onto PU does not significantly affect the thermal behavior or shape memory properties but sharply improves the tensile strength of the PU composites without a noticeable decrease in tensile strain. The shape recovery of PU composites remains at approximately 90%, regardless of the FGO or FG content. The FG-linked PU composites exhibit a sharp decrease in sheet resistance as the FG content increases, whereas the sheet resistance of the FGO-linked PU composites does not decrease with increasing FGO content. The control PU composites with blended RGO or graphite show significant reductions in their sheet resistance. Considering the ease of functionalization of the graphite surface and the significant improvement in tensile strength, linking FG onto PU is advantageous for the development of PU composites with low sheet resistance.

Buckypaper of polyvinyl chloride/p‐phenylenediamine modified graphite and PVC/graphite via resin infiltration technique

Resin‐infiltration technique has been employed as a versatile method to improve nanofiller dispersion in matrix. In this article, fabrication of polyvinyl chloride (PVC)/p‐phenylenediamine (PPD)/functional graphite (F‐G) and PVC/F‐G composite paper have been reported through resin‐infiltration techniques. Synthesis and characterization of PVC/PPD/F‐G and PVC/F‐G composite papers for enhanced structural, morphological, thermal, hardness, wettability, and conductivity properties have been studied. Moreover, the effect of increasing amount of F‐G and PPD/F‐G nanofiller on composite paper properties was scrutinized and compared. Transmission electron microscopy and scanning electron microscopy depicted better graphite nanofiller dispersion in PVC matrix and network formation in PVC/PPD/F‐G composite paper. Maximum degradation temperature (Tmax) of PVC/PPD/F‐G 0.08 composite paper (517°C) was found higher than PVC/F‐G 0.08 composite paper (484°C). Dynamic contact angle analysis shows that the PVC/PPD/F‐G and PVC/F‐G composite papers have better surface wettability than neat PVC. PVC/PDD/F‐G 0.1 and PVC/F‐G 0.1 composite papers possess high microhardness values up to 39.67 and 32.76 Hv, respectively. Electrical conductivity of 8.97 × 10−3 and 5.89 × 10−3 S m−1 was observed for 0.08 wt% PPD/F‐G and F‐G loaded samples. POLYM. COMPOS., 39:4176–4187, 2018. © 2017 Society of Plastics Engineers

Structure and properties of 4-aminobenzoic acid-modified polyvinyl chloride and functionalized graphite-based membranes

ABSTRACTIn this effort, series of polyvinyl chloride (PVC) and 4-aminobenzoic acid (4ABA)-modified PVC and functional graphite (FG)-based membranes were prepared. Fourier transform infrared spectroscopy and X-ray diffraction analysis were used to confirm PVC and graphite modification and nanocomposite formation. Scanning electron microscopy depicted homogenously layered morphology of modified PVC nanocomposite. Glass-transition temperature (Tg) of non-modified PVC nanocomposite was 243°C, whereas modified nanocomposite with similar FG loading had Tg of 258°C. Higher filler content furnished better hydrophilic membranes. Efficiency of PVC–4ABA-0.5/FG 0.5 membrane was 100% for removal of Hg2+ and Pb2+. PVC–4ABA-0.5/FG 0.5 membrane with smaller contact angle (30°) is a fine option for water purification.

Conductive Behaviour and Self-Conductance Characteristic of Carbon Nanotubes/Functionalized Graphene Hybrid Films

Multi-walled carbon nanotubes (MWCNTs)/Functionalized graphite (FG) hybrid films were fabricated by a simple solution-casting method. The films showed a layered, well-entangled and interconnected porous structure at nanometer scale. Such the nanostructures resulted in the films having the relatively high bulk conductivity and self-conductance characteristics. With increasing MWCNT mass fraction, the conductivity rapidly increased from approximately 10(-9) S/m of the host FG to over 10(-1) S/m. The percolation threshold was found to be about 29.6 wt% of MWCNTs. For the film with 83 wt% MWCNTs the specific capacitance was about 1 F/cm3. The hybrid films are of much higher power factor compared to conventional dielectric capacitors. The energy density of the film with 50 wt% MWCNTs was found to be 0.1 Wh/m3 and the charge-discharge period was very short about 8 seconds. It is believed that the MWCNTs/FG hybrid films have great potential as electrode materials for applications to energy storage.