scholarly journals Thermally Reduced Graphene Oxide/Thermoplastic Polyurethane Nanocomposites: Mechanical and Barrier Properties

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 85
Author(s):  
Santiago Maldonado-Magnere ◽  
Mehrdad Yazdani-Pedram ◽  
Héctor Aguilar-Bolados ◽  
Raul Quijada
Keyword(s):  
Graphene Oxide ◽  
Thermoplastic Polyurethane ◽  
Young Modulus ◽  
Barrier Properties ◽  
Thermal Reduction ◽  
X Ray Diffraction ◽  
Graphene Oxides ◽  
Melt Mixing ◽  
Mixing Processes ◽  
Reduced Graphene

This work consists of studying the influence of two thermally reduced graphene oxides (TRGOs), containing oxygen levels of 15.8% and 8.9%, as fillers on the barrier properties of thermoplastic polyurethane (TPU) nanocomposites prepared by melt-mixing processes. The oxygen contents of the TRGOs were obtained by carrying out the thermal reduction of graphene oxide (GO) at 600 °C and 1000 °C, respectively. The presence and contents of oxygen in the TRGO samples were determined by XPS and their structural differences were determined by using X-ray diffraction analysis and Raman spectroscopy. In spite of the decrease of the elongation at break of the nanocomposites, the Young modulus was increased by up to 320% with the addition of TRGO. The barrier properties of the nanocomposites were enhanced as was evidenced by the decrease of the permeability to oxygen, which reached levels as low as −46.1%.

scholarly journals Reduced Graphene Oxide and Polyaniline Nanofibers Nanocomposite for the Development of an Amperometric Glucose Biosensor

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 948
Author(s):  
Anton Popov ◽  
Ruta Aukstakojyte ◽  
Justina Gaidukevic ◽  
Viktorija Lisyte ◽  
Asta Kausaite-Minkstimiene ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Limit Of Detection ◽  
Thermal Reduction ◽  
Glucose Biosensor ◽  
Practical Application ◽  
X Ray Diffraction ◽  
Glucose Determination ◽  
Reduced Graphene ◽  
Graphite Rod

The control of glucose concentration is a crucial factor in clinical diagnosis and the food industry. Electrochemical biosensors based on reduced graphene oxide (rGO) and conducting polymers have a high potential for practical application. A novel thermal reduction protocol of graphene oxide (GO) in the presence of malonic acid was applied for the synthesis of rGO. The rGO was characterized by scanning electron microscopy, X-ray diffraction analysis, Fourier-transform infrared spectroscopy, and Raman spectroscopy. rGO in combination with polyaniline (PANI), Nafion, and glucose oxidase (GOx) was used to develop an amperometric glucose biosensor. A graphite rod (GR) electrode premodified with a dispersion of PANI nanostructures and rGO, Nafion, and GOx was proposed as the working electrode of the biosensor. The optimal ratio of PANI and rGO in the dispersion used as a matrix for GOx immobilization was equal to 1:10. The developed glucose biosensor was characterized by a wide linear range (from 0.5 to 50 mM), low limit of detection (0.089 mM), good selectivity, reproducibility, and stability. Therefore, the developed biosensor is suitable for glucose determination in human serum. The PANI nanostructure and rGO dispersion is a promising material for the construction of electrochemical glucose biosensors.

scholarly journals The The research to improve the mechanical properties and the water barrier properties of polyvinyl ancol film by graphen oxide

2020 ◽  
Vol 4 (2) ◽  
pp. First
Author(s):  
Nguyen Tuong Vy ◽  
Le Ha Vu Duy
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Young Modulus ◽  
Barrier Properties ◽  
Nanocomposite Films ◽  
Oxide Material ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Good Thermal Stability ◽  
Modified Hummers Method

In this study, graphene oxide (GO) is synthesized by a modified Hummers method, Polyvinyl alcohol (PVA) films and PVA/ GO nanocomposite films are prepared by casting stable aqueous mixed solutions. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) showed that there were a good compatibility and dispersion of graphene oxide (GO) on PVA matrix. In addition, nanocomposite films reinforced graphene oxide with the content of only 0.6 % phr have had 10.11% higher tensile strength, 12.24 % greater Young modulus, and significantly reduced water permeability during 4 hours of continuous immersion. Nanocomposite films maintained good thermal stability despite being added with graphene oxide, a material that is considered to have low thermal stability that easily decomposes below 200 oC, so thermal gravimetric analysis diagram (TGA) of PVA/ GO almost did not show a change compared to the neat PVA film. Initial results show that the efficiency of dispersing and reinforcing graphene oxide material on PVA resins has ameliorated the drawbacks of this polymer and contributed to extending the application of PVA in many areas. This has also reached closer to the goal of cleaning the environment by replacing non-biodegradable polymer sources with more friendly polymers.

scholarly journals Conductive Nanofilms with Oppositely Charged Reduced Graphene Oxides as a Base for Electroactive Coatings and Sensors

2021 ◽  
Vol 5 (2) ◽  
pp. 20
Author(s):  
Tomasz Kruk ◽  
Piotr Warszyński
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Low Cost ◽  
Thermal Reduction ◽  
Layer By Layer ◽  
Graphene Oxides ◽  
Lbl Assembly ◽  
Reduced Graphene ◽  
Amidation Reaction ◽  
Oppositely Charged

We demonstrate a method for the formation of multilayers composed of reduced graphene oxide (rGO), which can be used for transparent, conducting thin films. Using the layer-by-layer (LbL) assembly of positively and negatively charged GO sheets, we could obtain thin films with highly controllable sheet resistance. The natural negative charge of graphene oxide was turned to positive by the amidation reaction. After forming the multilayer films, the graphene oxide underwent thermal reduction at temperatures above 150 °C. The (rGO+/rGO−) films were characterized by UV-Vis and scanning electron microscopy (SEM), and their conductivity was measured by the four-point method. We found that after deposition of five (rGO+/rGO−), the coating structure reached the percolation limit, and the film resistance decreased more gradually to around 20 kΩ/sq for the films obtained by eleven deposition cycles with graphene oxide reduced at 250 °C. The formation of thin films on polyimide allows the forming of new flexible conductive materials, which can find applications, e.g., in biomedicine as new electroactive, low-cost, disposable sensors.

scholarly journals Magnetization of Ultraviolet-Reduced Graphene Oxide Flakes in Composites Based on Polystyrene

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2519
Author(s):  
Alexander N. Ionov ◽  
Mikhail P. Volkov ◽  
Marianna N. Nikolaeva ◽  
Ruslan Y. Smyslov ◽  
Alexander N. Bugrov
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Reduction Process ◽  
X Ray Diffraction ◽  
Mesoscopic Structure ◽  
Reduced Graphene ◽  
Study Results ◽  
Edge Defects ◽  
Mesoscopic Level ◽  
Ferromagnetic Hysteresis

This work presents our study results of the magnetization of multilayer UV-reduced graphene oxide (UV-rGO), polymer matrix (polystyrene), and a conjugated composite based on them. The mesoscopic structure of the composites synthesized in this work was studied by such methods as X-ray diffraction, SEM, as well as NMR-, IR- and Raman spectroscopy. The magnetization of the composites under investigation and their components was measured using a vibrating-sample magnetometer. It has been shown that the UV-reduction process leads to the formation of many submicron holes distributed inside rGO flakes, which can create edge defects, causing possibly magnetic order in the graphite samples under investigation on the mesoscopic level. This article provides an alternative explanation for the ferromagnetic hysteresis loop in UV-rGO on the base of superconductivity type-II.

Thermal reduction to control the spacing in graphene oxide membranes: effect on ion diffusion and electrical conduction

RSC Advances ◽  
2016 ◽  
Vol 6 (74) ◽  
pp. 70012-70017 ◽  
Author(s):  
A. Alhadhrami ◽  
S. Salgado ◽  
V. Maheshwari
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Electrical Conduction ◽  
Thermal Reduction ◽  
Electrochemical Characteristics ◽  
Ion Diffusion ◽  
Layer Spacing ◽  
Reduced Graphene ◽  
Oxide Membranes ◽  
Graphene Oxide Membranes

Inter-layer spacing in reduced graphene-oxide membranes which modulates their ion-diffusion electrical and electrochemical characteristics is controlled by temperature of thermal reduction.

Optical Characteristics of Multilayer Reduced Graphene Oxides Films Fabricated Using UV Oven Spraying Technique with Various Interval Irradiation Time

2021 ◽  
Vol 1028 ◽  
pp. 279-284
Author(s):  
Nur Khanifah ◽  
Diyan Unmu Dzujah ◽  
Vika Marcelina ◽  
Rahmat Hidayat ◽  
Fitrilawati ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Irradiation Time ◽  
Active Material ◽  
Reduction Process ◽  
Optical Characteristics ◽  
Graphene Oxides ◽  
Super Capacitor ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
Coating Method

Reduced graphene oxide (RGO) is promising candidate to be used as an active material of super capacitor electrodes. Graphene oxide (GO) is mostly used as a precursor, therefore it is needed to remove its oxygen containing functional groups. Generally, the RGO films are obtained from Graphene Oxide (GO) films which are then treated using thermal reduction or photo reduction process. We developed a spraying coating method that called as UV oven spraying by combining spraying coating method and photo reduction process. By this deposition method, we can obtain RGO films directly from the GO precursor since deposition and photo reduction steps are taken place at the same time. Level of oxygen removal of the obtained RGO film depends on irradiation intensity and length of irradiation. In this work, we report the effect of varied length of irradiation time on the RGO optical characteristics. We prepared multilayer of RGO films using UV oven spraying technique on quartz substrates from 0.5 mg/ml commercial GO dispersion (Graphenea) with varied the UV irradiation time. We used 125-Watt mercury lamp that was set at distance of 30 cm from substrates. We examined the effect of varied of length of irradiation time on its optical characteristics using UV-Vis Spectroscopy. Level of reduction by provided irradiation time was examined using SEM/EDS measurement.

scholarly journals Poly(3,4-ethylenedioxythiophene)-reduced graphene oxide/copper-based metal-organic frameworks as a high-performance symmetrical supercapacitor device

2021 ◽  
Author(s):  
Dharshini Mohanadas ◽  
Muhammad Amirul Aizat Mohd Abdah ◽  
Nur Hawa Nabilah Azman ◽  
Thahira B.S.A. Ravoof ◽  
Yusran Sulaiman
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
High Performance ◽  
Metal Organic Framework ◽  
Specific Power ◽  
X Ray Diffraction ◽  
Reduced Graphene ◽  
Metal Organic ◽  
Energy Storage Material ◽  
Organic Framework

Abstract A novel poly(3,4-ethylenedioxythiophene)-reduced graphene oxide/copper-based metal-organic framework (PrGO/HKUST-1) has been successfully fabricated by incorporating electrochemically synthesized poly(3,4-ethylenedioxythiophene)-reduced graphene oxide (PrGO) and hydrothermally synthesized copper-based metal-organic framework (HKUST-1). The field emission scanning microscopy (FESEM) and elemental mapping analysis revealed an even distribution of poly(3,4-ethylenedioxythiophene) (PEDOT), reduced graphene oxide (rGO) and HKUST-1. The crystalline structure and vibration modes of PrGO/HKUST-1 was validated utilizing X-ray diffraction (XRD) as well as Raman spectroscopy, respectively. A remarkable specific capacitance (360.5 F/g) was obtained for PrGO/HKUST-1 compared to HKUST-1 (103.1 F/g), PrGO (98.5 F/g) and PEDOT (50.8 F/g) using KCl/PVA as a gel electrolyte. Moreover, PrGO/HKUST-1 composite with the longest charge/discharge time displayed excellent specific energy (21.0 Wh/kg), specific power (479.7 W/kg) and outstanding cycle life (95.5%) over 4000 cycles. Thus, the PrGO/HKUST-1 can be recognized as a promising energy storage material.

Reduced Graphene Oxide Paper: Fabrication by a Green Thermal Reduction Method and Preliminary Study of its In Vitro Cytotoxicity

2017 ◽  
Vol 45 ◽  
pp. 199-207 ◽  
Author(s):  
Xin Wang ◽  
Peng Li ◽  
Claudia Luedecke ◽  
Qiang Zhang ◽  
Zan Wang ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Mammalian Cells ◽  
Reduction Method ◽  
Heating Temperature ◽  
Synthesis Method ◽  
Thermal Reduction ◽  
Graphene Films ◽  
Reduced Graphene

Graphene films have been intensively explored because of their unique mechanical and physicochemical properties for potential applications in field of tissue engineering and implants. However, for biomedical applications, it is necessary to fully understand the toxicity and biocompatibility of the prepared graphene films since different synthesis method might lead to different biological properties. Here we report a step-by-step thermal reduction method of preparing reduced graphene oxide (rGO) film directly on various substrates at low heating temperature (below about 200 °C) without requiring any chemical reduction agent like hydrazine or other reductants (therefore we call it green method). Slowly heating GO hydrosol that was coated on the surface of a glass cell-culture dish or inside of a polypropylene tube from room temperature to 60, 100, and 160 °C for 12 h, respectively, a shiny and flat surface without crumpled structure or tiny pores was formed. We peeled it off from the substrate to explore its cytotoxicity. The results exhibited that the rGO film was biocompatible with Cal-72 cell but against Escherichia coli bacteria. Our work confirmed that rGO film produced by the green reduction method is cytocompatible with mammalian cells, which makes this rGO film a promising material for tissue engineering scaffold or as a surface-modification coating of an implant.

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