scholarly journals Recent Advances in Graphene Oxide-Based Anticorrosive Coatings: An Overview

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1149
Author(s):  
Mădălina-Ioana Necolau ◽  
Andreea-Mădălina Pandele

The present review outlines the most recent advance in the field of anticorrosive coatings based on graphene oxide nanostructures as active filler. This carbonaceous material was extensively used in the last few years due to its remarkable assets and proved to have a significant contribution to composite materials. Concerning the graphene-based coatings, the synthesis methods, protective function, anticorrosion mechanism, feasible problems, and some methods to improve the overall properties were highlighted. Regarding the contribution of the nanostructure used to improve the capability of the material, several modification strategies for graphene oxide along with the synergistic effect exhibited when functionalized with other compounds were mainly discussed.

2021 ◽  
Vol 22 (10) ◽  
pp. 5401
Author(s):  
Marta Dziewięcka ◽  
Mirosława Pawlyta ◽  
Łukasz Majchrzycki ◽  
Katarzyna Balin ◽  
Sylwia Barteczko ◽  
...  

Interest in graphene oxide nature and potential applications (especially nanocarriers) has resulted in numerous studies, but the results do not lead to clear conclusions. In this paper, graphene oxide is obtained by multiple synthesis methods and generally characterized. The mechanism of GO interaction with the organism is hard to summarize due to its high chemical activity and variability during the synthesis process and in biological buffers’ environments. When assessing the biocompatibility of GO, it is necessary to take into account many factors derived from nanoparticles (structure, morphology, chemical composition) and the organism (species, defense mechanisms, adaptation). This research aims to determine and compare the in vivo toxicity potential of GO samples from various manufacturers. Each GO sample is analyzed in two concentrations and applied with food. The physiological reactions of an easy model Acheta domesticus (cell viability, apoptosis, oxidative defense, DNA damage) during ten-day lasting exposure were observed. This study emphasizes the variability of the GO nature and complements the biocompatibility aspect, especially in the context of various GO-based experimental models. Changes in the cell biomarkers are discussed in light of detailed physicochemical analysis.


2021 ◽  
Vol 18 (39) ◽  
pp. 43-55
Author(s):  
Alvaro ARRIETA ◽  
Jorge MENDOZA ◽  
Manuel PALENCIA

Background: Composite materials make it possible to modulate the properties of the source materials and expand their technological potential. In this sense, composite materials made from solid biopolymeric electrolytes and graphene oxide can be an attractive alternative for applications in organic electronics due to their electrochemical properties. Aim: The present work aims to evaluate the electrochemical behavior of a composite material made of solid biopolymeric electrolyte of cassava starch and graphene oxide at different concentrations to determine the effect of this concentration and the pH used in the production process. Methods: The composite material was made from the use of cassava starch plasticized with glycerol, glutaraldehyde, polyethylene glycol and with lithium perchlorate as electrolytes. During the synthesis process, graphene oxide was added in different concentrations (0, 0.25, 0.50, 1.00, 1.25, 1.50, and 1.75 %w/w) to evaluate the effect of the concentration of this component. The synthesis was carried out by thermochemical method with constant heating in an oven at 75 ° C for 48 hours. Films were prepared using synthesis solutions at different pH (5.0 and 9.0). The pH was regulated by adding HCl or NaOH to the synthesis solution as appropriate. Results and Discussion: The results showed that the cassava starch biopolymeric solid electrolyte films without plasticizers were stiff and brittle, so they broke easily. The films with plasticizers and the films of the composite material were stable to the manual traction, allowing their easy manipulation without breaking. The films presented a similar electrochemical behavior in terms of oxide reduction processes; however, the films with graphene oxide presented signals with higher peak currents. Films made at pH 9.0 showed 50 % more intensity in peak currents. The addition of graphene oxide affected the current parameters and peak potentials, being more marked in the films prepared at pH 9.0; at this pH the films with concentrations of graphene oxide lower than 1.00 %w/w presented variable Ep and Ip, while at concentrations of graphene oxide greater than 1%w/w, the behavior did not show significant variations. Conclusions: The addition of graphene oxide modulates or modifies the electrochemical behavior of cassava starch biopolymeric solid electrolyte films, and the processing pH can vary the effect of the graphene oxide addition.


2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Chao Li ◽  
Huijuan Li ◽  
Guicheng He ◽  
Zhiwu Lei ◽  
Wenyuan Wu

Photocatalytic technology is a widely used water treatment method, whose efficiency can be increased by developing a suitable photocatalyst fabrication procedure. In this study, five different synthesis methods were utilised for the preparation of novel ZnO/sepiolite photolytic composites, namely, sol-gel method, hydrothermal reduction, hydrolytic precipitation, powder sintering, and impregnation-reduction. The obtained photocatalysts were characterised by scanning electron microscopy, infrared spectroscopy, and X-ray diffraction. The differences between the applied photocatalyst preparation methods and the reasons for these differences were discussed, and the photocatalytic activities of the prepared composite materials were compared. The obtained results revealed that the physical structure, chemical properties, and photocatalytic performance of the composite produced by the sol-gel method were superior to those of the materials fabricated by the other four methods. Moreover, this material also exhibited high photocatalytic stability, while its photocatalytic degradation of methylene blue dye proceeded via a quasi-first-order reaction. The prepared composites have broad application prospects in photocatalysis and can be potentially used for treating environmental pollutants.


2021 ◽  
pp. 167-180
Author(s):  
M. A Tashkinov ◽  
A. D Dobrydneva ◽  
V. P Matveenko ◽  
V. V Silberschmidt

Сomposite materials are widely used in various industrial sectors, for example, in the aviation, marine and automotive industries, civil engineering and others. Methods based on measuring the electrical conductivity of a composite material have been actively developed to detect internal damage in polymer composite materials, such as matrix cracking, delamination, and other types of defects, which make it possible to monitor a composite’s state during its entire service life. Polymers are often used as matrices in composite materials. However, almost always pure polymers are dielectrics. The addition of nanofillers, such as graphene and its derivatives, has been successfully used to create conductive composites based on insulating polymers. The final properties of nanomodified composites can be influenced by many factors, including the type and intrinsic properties of nanoscale objects, their dispersion in the polymer matrix, and interphase interactions. The work deals with modeling of effective electric conductive properties of the representative volume elements of nanoscale composites based on a polymer matrix with graphene oxide particles distributed in it. In particular, methods for evaluating effective, electrically conductive properties have been studied, finite element modelling of representative volumes of polymer matrices with graphene oxide particles have been performed, and the influence of the tunneling effect and the orientation of inclusions on the conductive properties of materials have been investigated. The possibility of using models of resistive strain gauges operating on the principle of the tunneling effect is studied. Based on the finite-element modeling and graph theory tools, we created approaches for estimating changes in the conductive properties of the representative volume elements of a nanomodified matrix subjected to mechanical loading.


2017 ◽  
Vol 41 (2) ◽  
pp. 671-676 ◽  
Author(s):  
Zhenqing Dai ◽  
Qiongfang Lu ◽  
Qinguo Quan ◽  
Rijian Mo ◽  
Chunxia Zhou ◽  
...  

A low temperature chitosan hydrogel was fabricated under the synergistic effect of graphene oxide, and may be applied in hydrogel medical coatings.


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