Preparation of Expanded Graphite and Graphite Nanosheets for Improving Electrical Conductivity of Polyester Coating Films

2021 ◽  
Vol 21 (12) ◽  
pp. 5846-5858
Author(s):  
Yun Ding ◽  
Mingxia Tian ◽  
Aili Wang ◽  
Hengbo Yin
Keyword(s):  
Electrical Conductivity ◽  
Thermal Expansion ◽  
Milling Time ◽  
Expanded Graphite ◽  
Graphite Powder ◽  
Expandable Graphite ◽  
Coating Films ◽  
Natural Graphite ◽  
Graphite Nanosheets ◽  
Volumetric Rate

Expanded graphite and graphite nanosheets were facilely prepared by the thermal expansion of expandable graphite at 800 °C and sand milling of expanded graphite in water, respectively. When the expandable graphite precursor was prepared by the oxidation and intercalation of natural graphite (5 g) using KMnO4 (6 g) as an oxidant in a concentrated sulfuric acid solution (120 mL) at room temperature (25 °C) for 8 h, the expanded graphite with a maximum volumetric rate of 317 mL g−1 was prepared after the thermal expansion of the expandable graphite precursor at 800 °C for 60 s. The oxidation extent of natural graphite with KMnO4 is crucial for the preparation of expanded graphite. The thicknesses of graphite nanosheets decreased from 8.9 to 3.2 nm when the sand milling time of the expanded graphite in deionized water was prolonged from 6 to 24 h. The prolonging of the sand milling time not only decreased the layer number of the graphite nanosheet but also increased the d002 spacing due to the shocking and shearing forces. The addition of the expanded graphite powder and graphite nanosheets in a polyester paint efficiently improved the electrical conductivity of the resultant polyester coating films.

Effect of Expansion Temperature of Expandable Graphite on Anti-Friction Effect of Graphite Nonasheets from Sonicating Expanded Graphite

2011 ◽  
Vol 80-81 ◽  
pp. 225-228
Author(s):  
Wen Yan Duan
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Heating Temperature ◽  
Expanded Graphite ◽  
Expandable Graphite ◽  
Graphite Nanosheets ◽  
Friction Effect ◽  
Expansion Temperature ◽  
Scanning Electron

Three graphite nanosheets were prepared by sonicating three expanded graphites that were formed by rapidly heating expandable graphite at 600, 800 and 1000 °C, respectively. The graphite nanosheets were characterized by scanning electron microscope. The anti-friction effects of the graphite nanosheets used as lubricating additives were investigated. The results show that the size of the graphite nanosheets decreases with increasing the temperature of expandable graphite. The graphite nanosheets have an obvious anti-friction effect, and the effect is related to the heating temperature.

Structural Evolution of Natural Flake Graphite during Intercalation and Exfoliation

2014 ◽  
Vol 552 ◽  
pp. 328-330
Author(s):  
Zhi Guo Liu
Keyword(s):  
Intercalation Compound ◽  
Structural Evolution ◽  
Expanded Graphite ◽  
Expandable Graphite ◽  
Flake Graphite ◽  
Graphite Intercalation Compound ◽  
X Ray Diffraction ◽  
Natural Graphite ◽  
X Ray ◽  
Graphite Intercalation

In order to investigate the structural evolution of natural flake graphite during intercalation and exfoliation, natural graphite flakes were treated by intercalating, water-washing, drying and expanding. The corresponding products, graphite intercalation compound (GIC), residue GIC (expandable graphite) and expanded graphite were characterized by X-ray diffraction (XRD). The results can provide reference for the research in this field.

Preparing Graphite Nanosheets by Sonicating Expanded Graphite

2014 ◽  
Vol 552 ◽  
pp. 353-356
Author(s):  
Xue Qing Yue ◽  
Hua Wang ◽  
Wei Ma ◽  
Jun Shuang Tian
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Liquid Medium ◽  
Expanded Graphite ◽  
Average Diameter ◽  
Natural Graphite ◽  
Graphite Nanosheets ◽  
Water Washing ◽  
Scanning Electron

Natural Graphite Flakes were Treated by Intercalating, Water-Washing, Drying and Expanding, Forming Expanded Graphite. Graphite Nanosheets were Prepared by Sonicating Expanded Graphite in a Liquid Medium. the Corresponding Products were Characterized by Scanning Electron Microscope. the Results Show that the Graphite Nanosheets as-Prepared have an Average Diameter of 16μm and an Average of Thickness of 25 Nm.

Expansion Mechanism of Expandable Graphite Formed by Natural Graphite with Different Particle Size

2012 ◽  
Vol 499 ◽  
pp. 16-19
Author(s):  
Meng Lu Wang ◽  
Li Ji
Keyword(s):  
Particle Size ◽  
Expanded Graphite ◽  
Expansion Ratio ◽  
Microwave Oven ◽  
Raw Material ◽  
Expandable Graphite ◽  
Particle Sizes ◽  
Natural Graphite ◽  
Expansion Mechanism

Using three natural graphites with different particle sizes, 80, 50 and 35 mesh, as raw material, three expanded graphites were prepared by irradiating expandable graphite in a microwave oven. Results show that the particle size of natural graphite influences strongly the expansion ratio of expanded graphite, and the larger the particle size, the larger the expansion ratio. In addition, the expansion mechanism of expandable graphite is discussed.

Effect of Particle Size of Natural Graphite on Methyl Blue Sorption Behavior of Expanded Graphite

2012 ◽  
Vol 499 ◽  
pp. 12-15 ◽  
Author(s):  
Li Ji ◽  
Meng Lu Wang
Keyword(s):  
Particle Size ◽  
Removal Rate ◽  
Expanded Graphite ◽  
Expansion Method ◽  
Treatment Method ◽  
Raw Material ◽  
Methyl Blue ◽  
Expandable Graphite ◽  
Sorption Behavior ◽  
Natural Graphite

Using three natural graphites with different particle sizes, 80, 50 and 35 mesh, as raw material, expanded graphite was prepared by rapidly heating expandable graphite in a muffle and by irradiating it in a microwave oven, respectively. The resulting expanded graphites were used for adsorbing methyl blue in water. The results show that the removal rate of methyl blue is influenced by the treatment method of solution, the particle size of natural graphite and expansion method of expandable graphite. After selection of desired operation parameters, a higher removal rate is achieved.

Highly electrically conducting poly(L-lactic acid)/graphite composites prepared via in situ expansion and subsequent reduction of graphite

2018 ◽  
Vol 38 (2) ◽  
pp. 167-177 ◽  
Author(s):  
Bai Xue ◽  
Lanxiang Ji ◽  
Jianguo Deng ◽  
Junhua Zhang
Keyword(s):  
Electrical Conductivity ◽  
Lactic Acid ◽  
Percolation Threshold ◽  
Reduction Process ◽  
Expanded Graphite ◽  
Xrd Analysis ◽  
Expandable Graphite ◽  
Subsequent Reduction ◽  
Electrically Conducting

AbstractIn this paper, highly electrically conductive polymeric composites were obtained by low-temperature expandable graphite (LTEG) filling poly(L-lactic acid) (PLLA) in the presence of ascorbic acid via anin situexfoliation and subsequent reduction process during the melt blending. The electrical conductivity of the PLLA/reduced and expanded graphite (R-EG) composites was determined by a four-point probe resistivity determiner and compared with that of the PLLA/expanded graphite (EG) composites. The percolation threshold of PLLA/R-EG blends decreased from 11.2 wt% to 7.1 wt%, which illustrated the superiority of R-EG to the electrically conducting ability of PLLA composites. At the graphite concentration near the percolation threshold, the electrical conductivity of PLLA/R-EG composites was much higher than that of PLLA/EG composites. The effectivein situexpansion and reduction of LTEG were crucial to the overall electrical conductivity of the blends, which was confirmed by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analysis. Dynamic rheology analysis confirmed that the connected networks that were the major cause of the rapid increase in electrical conductivity were much more easily formed for PLLA/R-EG blends than those of PLLA/EG blends. Thermogravimetric analysis (TGA) was applied to determine the decomposition and thermal stability of the PLLA/R-EG composites.

Preparation and Characterization of Conductive Polymer Nanocomposites Based on Ethylene–Vinylacetate Copolymer (EVA) Reinforced with Expanded and Unexpanded Graphite

2015 ◽  
Vol 1114 ◽  
pp. 92-99
Author(s):  
Ismail H. Tavman
Keyword(s):  
Electrical Conductivity ◽  
Thermal Diffusivity ◽  
Thermal Cycling ◽  
Polymer Nanocomposites ◽  
Conductive Polymer ◽  
Young Modulus ◽  
Expanded Graphite ◽  
Filler Concentration ◽  
Melt Mixing ◽  
Natural Graphite

Recently polymer nanocomposites are used more and more frequently in industry due to the fact that the properties of the polymers can be altered to the specific requirements by the addition of particles and fibers of different properties, shapes. Polymers are poor thermal and electrical conductors, conductive fillers such as metallic powders, carbon black, graphite, are usually incorporated into polymer matrix to produce conducting composites. In this study composites were prepared using ethylenevinyl acetate (EVA) copolymer as matrix filled with two kinds of reinforcement graphite materials: untreated natural graphite (UG) and expanded graphite (EG). Composite samples up to 29.3 % graphite particle volumetric concentrations (50 % mass concentration) were prepared by the melt mixing process in a Brabender Plasticorder. Upon mixing, the EG particles originally 5μm to 6μm in size, exfoliates in the form of nanosheets having a few nanometer thickness; they have very big surface areas with high aspect ratio ranging between 20 and 250, as evidenced by TEM micrographs. From the experimental results it was deduced that the electrical conductivity was not only a function of filler concentration, but also strongly dependent on the graphite structure. The percolation concentration of the filler was found to be (15 to 17) vol% for micro-sized natural graphite, whereas the percolation concentration of the filler in nanocomposites filled with expanded graphite was much lower, about (5 to 6) vol%. The electrical conductivity of nanocomposites was also much higher than the electrical conductivity of composites filled with micro-sized filler at similar concentrations. Similarly, the values of the thermal diffusivity for the nanocomposites, EG-filled EVA, were significantly higher than the thermal diffusivity of the composites filled with micro-sized filler, UG-filled EVA, at similar concentrations. The effect of thermal cycling on the tensile behavior of EVA composites containing 4% and 15% of UG by mass and 6% and 15% of EG by mass were subjected to thermal cycling between-25 to +60 °C. Tension tests were conducted after thermal cycling for 50 and 100 cycles. Tensile strength remained practically unchanged after thermal cycling, while the Young modulus increased appreciably with the number of thermal cycle.

scholarly journals Transport Properties of Natural and Artificial Smart Fabrics Impregnated by Graphite Nanomaterial Stacks

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1018
Author(s):  
Carola Esposito Corcione ◽  
Francesca Ferrari ◽  
Raffaella Striani ◽  
Antonio Greco
Keyword(s):  
Electrical Conductivity ◽  
Transport Properties ◽  
Low Cost ◽  
Empirical Relationship ◽  
Theoretical Models ◽  
Expandable Graphite ◽  
Easy Method ◽  
Textile Materials ◽  
Fabric Materials ◽  
The Impact

In this work, we studied the transport properties (thermal and electrical conductivity) of smart fabric materials treated with graphite nanomaterial stacks–acetone suspensions. An innovative and easy method to produce graphite nanomaterial stacks–acetone-based formulations, starting from a low-cost expandable graphite, is proposed. An original, economical, fast, and easy method to increase the thermal and electrical conductivity of textile materials was also employed for the first time. The proposed method allows the impregnation of smart fabric materials, avoiding pre-coating of the fibers, thus reducing costs and processing time, while obtaining a great increase in the transport properties. Two kinds of textiles, cotton and Lycra®, were selected as they represent the most used natural and artificial fabrics, respectively. The impact of the dimensions of the produced graphite nanomaterial stacks–acetone-based suspensions on both the uniformity of the treatment and the transport properties of the selected textile materials was accurately evaluated using several experimental techniques. An empirical relationship between the two transport properties was also successfully identified. Finally, several theoretical models were applied to predict the transport properties of the developed smart fabric materials, evidencing a good agreement with the experimental data.

Effects of the Mould Pressure and Mould Pressing Time on the Properties of Graphite/Phenolic Resin Composites

2013 ◽  
Vol 706-708 ◽  
pp. 95-98
Author(s):  
Mi Dan Li ◽  
Dong Mei Liu ◽  
Lu Lu Feng ◽  
Huan Niu ◽  
Yao Lu
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Flexural Strength ◽  
Polymer Matrix ◽  
Phenolic Resin ◽  
Polymer Matrix Composites ◽  
Resin Composites ◽  
Matrix Composites ◽  
Natural Graphite ◽  
Pressing Time

Polymer matrix composites made from phenolic resin are filled with natural graphite powders. They are fabricated by compression molding technique. The density, electrical conductivity and flexural strength of composite are analyzed to determine the influences of mould pressure and mould pressing time on the physical, electrical and mechanical properties of composite. It is found that the density, electrical conductivity and flexural strength of composites increased with increasing mould pressure. Under pressure of 40 MPa for 60 min, the density, electrical conductivity and flexural strength of composites were 1.85 g/cm3, 4.35  103 S/cm and 70 MPa, respectively. The decreased gaps could be the main reason for the increasing of density, electrical conductivity and flexural strength as mould pressure increases. The results also show that the density of composites increased with increasing mould pressing time.

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