Author: Energeia Graphenemex

Graphene: The next revolution in biomedical applications

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Graphene:

The next revolution in biomedical applications

Part I. Tissue Engineering

Advances in medicine have reached levels unimagined until recently. Among them, tissue engineering has an important participation. With it is possible to combine cells, biomaterials and biologically active molecules with the aim of repairing or replicating tissues or organs with a function similar to that of the original structure. In principle, biomaterials are used as molecular scaffolds to act as a three-dimensional (3D) support or guide for the anchoring and growth of the cells that will be in charge of forming the new tissue.

The first molecular scaffolds were designed with natural materials such as collagen, glycosaminoglycans (GAGs), chitosan, and alginates; then with artificial compounds such as polylactic acid (PLA), polyglycolic acid (PGA), poly(lactic-co-glycolic) acid (PLGA), polyurethanes (PUs), polytetrafluoroethylene (PTFE), polyethyleneterephthalate (PET); bioceramics such as hydroxyapatite (HA) and tricalcium phosphate; metals such as stainless steel, chrome-cobalt alloys (Co-Cr) or titanium alloys (Ti) and recently, new research is oriented towards the use of nanotechnology.

The relationship between nanotechnology and tissue engineering is due to the fact, that the extracellular matrix (ECM) that helps cells unite and communicate with each other, is made up of a network of nanometer-sized fibers made up of bioactive molecules. It is at this point where nanotechnology opens new possibilities for regenerative medicine, since it has been proven that the use of materials that act on the same nanometric scale as the ECM favors mimicking the physiological environment of the organism to stimulate cell growth and differentiation in a more natural environment.

Among the most studied nanomaterials in recent years are graphene materials, which consist of nanometric sheets of carbon atoms organized in two-dimensional (2D) hexagonal networks. Among the most interesting properties for tissue engineering are: its large surface area, mechanical resistance, thermal conductivity, biocompatibility and finally, an extraordinary ability to share its properties with other materials to improve their original characteristics.

For example, the use of graphene materials within the 3D architecture of certain biopolymers in tests carried out on heart, liver, bone, cartilage, and skin tissues has shown substantial improvements in their physicochemical, mechanical, electrical and biological properties, achieving excellent response. for stem cell adhesion and differentiation.

In 2022, the Andaltec technology center (Spain) reported the development of a material from polymers derived from graphene by 3D printing with great potential for the regeneration of muscle tissue. They demonstrated that in the presence of graphene derivatives, cells contract and expand without an external stimulus, therefore, it has great potential for use in regenerative medicine.

On the other hand, the Division of Postgraduate Studies and Research (DEPeI) on Odontology, UNAM and the National School of Higher Studies (ENES) León Unit, Mx., through a study published in J Oral Res 2021 supports the possibilities of graphene oxide (GO) in the design of biomaterials for dental use. The results of the research carried out with Graphenemex® GO samples, concluded that this nanomaterial in combination with polymethylmethacrylate (PMMA), in addition to improving its physical-mechanical properties, also demonstrated good compatibility and an interesting stimulation of cell proliferation when being evaluated on cultures with gingival-fibroblasts, dental-pulp-cells and human osteoblasts.

In 2020, researchers from the University of Malaga (Spain) published another study that identified GO as the ideal material for regenerative medicine. The study carried out on an animal model, showed high biocompatibility of different types of graphene oxide with dopaminergic cells, favoring their maturation and protecting them from the toxic conditions of Parkinson’s disease. These results postulate GO as an adequate scaffold to test new drugs or develop constructs for cell replacement therapy of Parkinson’s disease.

Despite the large amount of research on the interactions of graphene materials with biological media, there is still a long way to go to have these biomaterials available and in clinical operation. Energeia- Graphenemex, the pioneering Mexican company in Latin America in the research and development of applications with graphene materials, in collaboration with other companies and research centers, seeks to contribute with science to understand these interactions in a security framework, to lay solid foundations on the use of graphene nanotechnology in the biomedical sector for the benefit of society.

Drafting: EF/DHS

References

  1. Graphene and its derivatives: understanding the main chemical and medicinal chemistry roles for biomedical applications. J Nanostructure Chem, 2022, 12:693
  2. Biological and physico-mechanical properties of poly (methyl methacrylate) enriched with graphene oxide as a potential biomaterial. J Oral Res 2021; 10(2):1
  3. Graphene-Based Antimicrobial Biomedical Surfaces. ChemPhysChem 2021, 22, 250
  4. Functionalized Graphene Nanoparticles Induce Human Mesenchymal Stem Cells to Express Distinct Extracellular Matrix Proteins Mediating Osteogenesis. Int J Nanomed 2020:15 2501
  5. Graphene Oxide and Reduced Derivatives, as Powder or Film Scaffolds, Differentially Promote Dopaminergic Neuron Differentiation and Survival. Front. Neurosci., 21 December 2020. Sec. Neuropharmacology Volume 14
  6. International Journal of Nanomedicine 2019:14 5753
  7. Biocompatibility Considerations in the Design of Graphene Biomedical Materials. Adv. Mat. Interfaces 2019, 6, 1900229
  8. Graphene based scaffolds on bone tissue engineering. Bioengineered, 2018, 9:1, 38
  9. When stem cells meet graphene: Opportunities and challenges in regenerative medicine. Biomaterials, 2018, 155, 236
  10. Graphene-based materials for tissue engineering. Adv. Drug Deliv. Rev. 2016,105, 255

Chapter 92 e: Tissue Engineering, Anthony Atala. 2023 McGraw Hill.

Improve safety with flame retardant polymeric compounds with graphene oxide

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Improve safety with flame retardant polymeric compounds

with graphene oxide

Polymeric compounds (engineering plastics) are widely used in the automotive, construction, food, aerospace and other sectors. Its use is based on the weight/resistance ratio, physical stability, chemical resistance and corrosion resistance.

However, most polymers, due to their nature, are flammable and combustible. That is, they are materials that catch fire quickly when exposed to fire, undergoing degradation, Veo complicadoand releasing heat to later start the propagation of the flames. During the combustion of polymers, they release smoke (soot) and toxic gases that are a danger to the safety of human life and property.

Four key components are involved during the combustion of polymeric materials: heat, oxygen, fuel, and free radical reaction. Flame retardancy of polymeric composites can be achieved by inhibiting or perturbing one or more of these components.

In recent years, multiple investigations have been carried out to develop additives that help inhibit or reduce the flammability of polymers, these additives are known as flame retardants.

Conventional flame retardants can be classified into two main categories, based on their components: inorganic flame retardants and organic flame retardants. The first include hydroxide, metal oxide, phosphate, silicate among others. They have excellent thermal stability, are non-toxic, are low cost and do not produce pollution. However, inorganic flame retardants are limited by high loading, low compatibility, and aggregation. On the other hand, organic flame retardants include flame retardants containing halogens, phosphorous, phosphorous-nitrogen, etc. The latter have high efficiency and good compatibility with polymers. Their main disadvantage is that they are restricted because they can release toxic gases and be harmful during combustion, endangering the health of people and the environment.

Graphene oxide (GO) is currently the most novel nanomaterial for use as a flame retardant because it exhibits high efficiency as a retardant with low loads and is non-toxic. Its efficiency is associated with the fact that graphene oxide has a strong barrier effect, high thermal stability and great surface absorption capacity, which are favorable for reducing heat and mass transfer.

Graphene-based flame retardants can improve the flame resistance of polymers by inhibiting the two key terms: heat and fuel. More specifically, graphene oxide can function as a flame retardant in different synergistic ways.

  1. First of all, GO has a unique two-dimensional layer structure and can promote the formation of a continuous dense layer of carbon during the combustion process. Carbon can act as a physical barrier to prevent heat transfer from the heat source and delay the escape of products (pyrolysis) from the polymeric substrate.
  2. Second, GO has a large specific surface area and can effectively adsorb flammable volatile organic compounds or hinder their release and diffusion during combustion.
  3. Third, GO contains abundant reactive oxygen-containing groups (carboxyl group at the edges, as well as epoxy and hydroxyl groups at the basal planes in the sheets). For example, oxygen-containing groups can undergo decomposition and dehydration at low temperatures, thus absorbing heat and cooling the polymeric substrate during combustion. Meanwhile, the gases generated by dehydration can dilute the oxygen concentration around the ignition periphery, decreasing the risk of fire spread.
  4. It can also modify the rheological behavior of the polymer and prevent its dripping, thus hindering the release and diffusion of volatile decomposition products through the ”maze effect” and affecting the flame retardancy of compounds (for example, modifying the UL-94 classification, oxygen index (OI) and time to ignition (TTI).

In studies carried out, it has been found that the incorporation of functionalized graphene oxide (5% by weight) in Polypropylene (PP) increased the Young’s modulus and the elastic limit of PP by 53% and 11%, respectively. While in the results of the flammability test (UL-94), it indicates that the presence of GO produces a change in the behavior of the melt and prevents the material from dripping.

On the other hand, the preparation of polymeric compounds in melt blending (extrusion) of Polystyrene/GO have been reported, where it was found that GO (5%) can promote carbonization on the polymer surface (layer of carbonized material). and inside, the presence of a load or filler that presents high resistance to heat and contributes to the formation of carbon residues, improving the flame resistance of polystyrene-based compounds.

Currently Energeia – Graphenemex®, a leading Mexican company in Latin America in research and production of graphene materials for the development of applications at an industrial level, through its Graphenergy Masterbatch line, has developed a wide range of masterbatches with graphene oxide, based on various polymers, such as PP, HDPE, LDPE, PET and PA6.

The incorporation of graphene and graphene derivatives (GO) to polymeric matrices has allowed the development of polymeric compounds with better mechanical properties, greater thermal stability, gas barrier capacity and reduced flammability of polymeric compounds.

References

  1. Han Y, Wu Y, Shen M, Huang X, Zhu J, Zhang X. Preparation and properties of polystyrene nanocomposites with graphite oxide and graphene as flame retardants. J Mater Sci 48:4214.
  2. Hofmann D, Wartig K-A, Thomann R, Dittrich B, Schartel B, Mu¨lhaupt R. Functionalized graphene and carbon materials as additives for melt-extruded flame retardant polypropylene. Macromol Mater Eng 298:1322.
  3. Dittrich B, Wartig K-A, Hofmann D, Mu¨lhaupt R, Schartel B. Flame retardancy through carbon nanomaterials: carbon black, multiwall nanotubes, expanded graphite, multi-layer graphene and graphene in polypropylene. Polym Degrad Stab 98:1495.

Innovation in the plastics industry: how graphene masterbatches are changing the game

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Innovation in the plastics industry:

how graphene masterbatches are changing the game

Graphene has extraordinary electrical, optical, thermal properties and high mechanical resistance. The properties of graphene are attributed to its structure in the form of two-dimensional (2D) sheets, formed by hexagonal bonded carbon atoms and a thickness of one carbon atom.

Today, graphene is the most promising nanotechnological additive in the plastics industry. The incorporation of graphene and its derivatives (graphene oxide, GO) in different polymer matrices (masterbatches), have great potential for a wide range of applications. The graphene masterbatch can act as a mechanical reinforcement or conductive additive for both thermoplastic and thermosetting materials. They can be used in the automotive, aerospace, electronics or packaging sectors.

Graphene-based polymeric compounds have shown significant improvements in properties such as elastic modulus, tensile strength, impact resistance, electrical conductivity, resistance to UV radiation, thermal stability, antimicrobial property, impermeability or barrier effect (it does not allow the diffusion of moisture or other molecules).

Currently Energeia – Graphenemex®, a leading Mexican company in Latin America in research and production of graphene materials for the development of applications at an industrial level, through its Graphenergy Masterbatch line, has developed and sells a wide range of masterbatches with graphene, based on various polymers, such as PP, HDPE, LDPE, PET and PA6.

Our Masterbatches are granular materials that act as multifunctional additives. The incorporation of graphene in different polymer matrices has shown important effects on the properties and processing conditions of plastics, among which are:

  • Increased resistance to tension, deformation and impact
  • Increased resistance to ultraviolet rays
  • Excellent dispersion
  • Improves processing conditions (thermal stability)
  • Acts as a nucleating agent (modification of the crystallization temperature of the polymer)

In this sense, it has been found that the incorporation of graphene and its derivatives, as well as the concentration, can modify the physicomechanical properties of the polymer to be processed. The addition of masterbatch to different polymers has improved the final characteristics of the material to a lesser or greater extent, for example:

  • Additivation of Polypropylene (PP) with polypropylene-graphene masterbatch (MB-PP/GO), increases tensile strength (8%) and rupture percentage (29%).
  • Additivation of Polyethylene (PE) with polyethylene-graphene masterbatch (MB-PE/GO), improves tensile strength (17%), flexural strength and rupture strength (66%).
  • Additivation of Polyethylene terephthalate (PET) with polyethylene terephthalate-graphene masterbatch (MB-PET/GO), improves resistance to humidity, increases tensile strength (72.2%) and improves impact resistance.
  • Additivation of Polycarbonate (PC) with polycarbonate-graphene masterbatch (MB-PC/GO), improves resistance to humidity and improves resistance to rupture (276%).

On the other hand, graphene masterbatches can also be incorporated into recycled polymers. Currently, the reuse and recycling of plastic materials are of vital importance in the transition path towards a circular economy. In this regard, the constant washing, pelletizing and reprocessing can cause the loss of physicomechanical properties of recycled plastics, therefore, by adding graphene, these properties can be restored or improved. In agricultural applications, mulch films with increased resistance to ultraviolet radiation can be produced.

References

  1. Fang, M., et al., Covalent polymer functionalization of graphene nanosheets and mechanical properties of composites. Journal of Materials Chemistry. 19(38): p. 7098-7105.
  2. Kim, H., A.A. Abdala, and C.W. Macosko, Graphene/Polymer Nanocomposites. Macromolecules. 43(16): p. 6515-6530.
  3. Balandin, A.A., et al., Superior Thermal Conductivity of Sin gle-Layer Graphene. Nano Letters, 8(3): p. 902-907.
  4. Nabira Fatima, Umair Yaqub Qazi, Asim Mansha., Recent developments for antimicrobial applications of graphene-based polymeric composites: A review, https://doi.org/10.1016/j.jiec.2021.04.050

Graphene as a sustainable alternative for water purification

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Graphene as a sustainable alternative

for water purification

Graphene materials, that is, Graphene, Graphene Oxide (GO) and Reduced Graphene Oxide (rGO), are carbon nanostructures that, thanks to their size, area, and surface chemistry, allow the design o new three-dimensional and multifunctional materials with high probabilities. to solve the problems associated with water scarcity.

For example, they are potential coagulant/flocculating agents, this is because they have a large surface area along which there are multiple anchor points capable of capturing a large amount of organic and inorganic matter, that is, they are highly useful for the capture of contaminants.

Main strategies for the use of graphene materials for the capture of contaminants.
  Taken from Environ. Sci. Technol., 2012, 46, 7717.

They are also chemically inert and by being immobilized in a substrate they prevent organic matter from adhering to surfaces. This property, when implemented in membrane technology, would allow a flow of water almost without friction, in other words, the use of graphene materials could make the flow of water remain constant for longer and therefore provide greater energy efficiency.

Likewise, their nanometric size, the arrangement of their sheets and the presence of millions of nanochannels between them make them highly impermeable, acting as a filter for molecules or contaminants.

Ion and water transport through graphene nanochannels.
Taken from J. Phys. Chem. C 2020, 124, 31, 17320.

Finally, the important antimicrobial and photocatalytic properties of graphene and its derivatives, in addition to reducing the microbial load by taking advantage of sunlight, would also help to reduce the requirements for biocidal agents.

Schematic representation of graphene in 3D structures for water purification.
Taken from Gels 2022, 8, 622.

The identification, understanding and use of the properties of graphene for the development of real products has not been an easy task. However, on November 3, 2022, the Graphene flagship, the multidisciplinary project in which almost 10 years ago the European Commission invested 1,000 million euros for Graphene research, announced the results of the Graphil Project, which consisted of the development of a new polysulfone filter with Graphene Oxide that acts as a more efficient mechanical network to trap polluting particles such as heavy metals, antibiotics, viruses, bacteria, toxins, etc., while allowing the passage of clean and safe water.

For its part, Energeia-Graphenemex®, the pioneering Mexican company in Latin America in the research and development of applications with graphene materials, in collaboration with other companies and research centers, joins this search for strategies to improve the availability and quality of water through the use of graphene, hoping in the short term to have all these benefits available to society.

References:

  1. Yu Z, Wei L, Lu L, Shen Y, Zhang Y, Wang J, Tan X. Structural Manipulation of 3D Graphene-Based Macrostructures for Water Purification. Gels. 2022, 29; 8(10):622.
  2. Alessandro Kovtun, Antonio Bianchi, Massimo Zambianchi, Cristian Bettini, Franco Corticelli Giampiero Ruani, Letizia Bocchi,Francesco Stante,Massimo Gazzano, Tainah Dorina Marforio, Matteo Calvaresi, Matteo Minelli,Maria Luisa Navacchia, Vincenzo Palermo and Manuela Melucci. Core–shell graphene oxide– polymer hollow fibers as water filters with enhanced performance and selectivity. Faraday Discuss., 2021, 227, 274.
  3. Sebastiano Mantovani,Sara Khaliha, Laura Favaretto, Cristian Bettini,Antonio Bianchi, Alessandro Kovtun, Massimo Zambianchi, Massimo Gazzano,  Barbara Casentini, Vincenzo Palermo and Manuela Melucci. Scalable synthesis and purification of functionalized graphene nanosheets for water remediation. Chem. Commun., 2021, 57, 3765
  4. Sara Khaliha, Tainah D. Marforio, Alessandro Kovtun, Sebastiano Mantovani, Antonio Bianchi, Maria Luisa Navacchia, Massimo Zambianchi, Letizia Bocchi. Nicoals Boulanger. Artem Iakunkov, Matteo Calvaresi, Alexandr V. Talyzin, Vincenzo Palermo, Manuela Melucci. Defective graphene nanosheets for drinking water purification: Adsorption mechanism, performance, and recovery. FlatChem., 2021, 29 100283.
  5. Yunzhen Zhao, Decai Huang, Jiaye Su, and Shiwu Gao. Coupled Transport of Water and Ions through Graphene Nanochannels. J. Phys. Chem. C 2020, 124, 31, 17320
  6. F. Guo, G. Silverberg, S. Bowers, S.-P. Kim, D. Datta, V. Shenoy and R. H. Hurt, Environmental Applications of Graphene-Based Nanomaterials. Environ. Sci. Technol., 2012, 46, 7717
  7. https://graphene-flagship.eu/graphene/news/graphene-applications-graphil/

Graphene-reinforced lime paints: the revolution in the construction industry

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Graphene-reinforced lime paints:

the revolution in the construction industry

Although the exact date on which lime was discovered by man is not known, there are records dating back more than 14,000 years regarding its use. In the case of Mexico, it has been used since pre-Hispanic times both for construction and for nixtamalization, in ancient Greece it was used to color numerous frescoes (2800 B.C.- 1000 A.D.), the Chinese wall was built after stabilizing the soil with lime (500 AD) and among many other historical data, lime became popular in Europe during the Middle Ages for its disinfectant, breathable and fire-retardant properties, being used mainly as a coating on the exterior of houses and barracks. Subsequently, its implementation in the cities extended until the beginning of 1900 and it was not until the middle of that same century that it reached rural areas, a period in which synthetic paints gained ground over lime thanks to their ease of application, wide range of colors and low cost.

However, at the end of the 1970s and due to the awareness of the dangers of some synthetic paints with respect to health and the environmental pollution caused by certain components (heavy metals and volatile organic compounds [VOC]), lime paints once again had a boom as they are safer products and have a smaller footprint on the environment.

Among the benefits of lime-based paints or coatings are that they are 100% natural, ecological and VOC-free products, which absorb CO2 during their hardening process, which means that their use contributes to air purification. They are also breathable materials, that is, they allow the structures to “breathe” and do not concentrate moisture. In addition, they are thermoregulators, this means that they do not allow drastic changes in temperature in the buildings and, on the contrary, they help the buildings to stay cool.

However, and despite their great advantages, one of the main drawbacks of lime-based paints is their high permeability and, therefore, poor resistance to humidity, which is in turn related to limited adherence that requires constant repair work. maintenance. On the other hand, and although antimicrobial or biocidal properties are attributed to lime, it is not convenient to ensure that all the products that contain it offer this protection, since they are materials susceptible to being attacked by microbial species such as Aspergillus spp., Cladosporium spp, Fusarium spp., Trichoderma spp., Actinobacteria and Bacteroidetes among other species responsible for its biodeterioration as well as some infections.

With the aim of contributing to a sustainable present and future, in 2022 the strategic alliance between the companies Energeia-Graphenemex® and Oxical®, after almost 2 years of research, launched a new coating made from modified high-purity lime with Graphene nanoparticles, under the Graphenecal® brand.

Graphenecal nanoengineering reaches the market to create a new generation of lime-based coatings that exceed the characteristics of water-based paints made from chemical resins. The nanometric network that generates the graphene nanoparticles in combination with the high-purity lime and other natural products used in its formulation, compacts and organizes its entire structure at the molecular level, offering greater durability to the coating and improving its characteristics, thanks to the perfect balance that exists between greater impermeability (>50-80%) with adequate breathability avoiding the accumulation of moisture on surfaces, coupled with the excellent benefits offered by its great antimicrobial capacity (>99.9%) that prevents the adhesion and formation of microbial biofilms not only to protect against the biodeterioration of structures but also as a tool in infection control, among other advantages such as excellent adhesion, covering power, resistance against the effects of weather, greater thermoregulation, CO2 capture and lower carbon footprint in comparison with other products, no need for chemical additives, biocide products or contaminants, placing Mexico at the vangard in the development of environmentally friendly products.

Greater Impermeability

After 4 days of application, Graphenecal is 50% more waterproof than lime-based paints without graphene. As of day 30, this property rises to 85% without affecting the breathability of the product.
Representative image of the impermeability of Graphenecal on two different substrates.

Antimicrobial Capacity

On the graphene-free lime paint, a microbial biofilm was formed on more than 90% of its surface. The Graphenecal coated area remained free of contamination during the test.

Innovation in corrosion protection: graphene oxide technology

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Innovation in corrosion protection:

graphene oxide technology

Corrosion is the greatest challenge that many industries in the world must face. Currently, there is a wide variety of coatings on the market for protection against corrosion. However, most of these coatings do not have the physicochemical characteristics necessary for good performance. These coatings does not have perfect barriers and eventually fail, their chemical resistance depends on their impermeability to chemical substances, and with it their resistance to abrasion and their adhesion capacity.

Currently Energeia – Graphenemex®, a leading Mexican company in Latin America in the research and production of graphene materials for the development of industrial applications, has a wide range of coatings through its Graphenergy line.

Graphenergy is the line of nanotechnological coatings with graphene oxide, which has a complete portfolio of high-performance anticorrosive coatings for Industrial and Infrastructure maintenance.

Taking into account that the infrastructure or industrial equipment may be exposed to environments with different degrees of corrosion (intermediate or extreme), the use of Coating Systems for corrosion protection is recommended, Graphenergy offers the following alternatives:

1. ALKYD SYSTEM

Recommended for intermediate or mild corrosion environments (intermediate corrosive or aggressive conditions). This system is weather resistant and provides anticorrosive protection.

This system is made up of a primer and alkyd-type enamel, ideal for the protection of metal surfaces and industrial infrastructure, both for interiors and exteriors. Provides high anticorrosive protection, resistance to UV rays and provides extraordinary adherence to the substrate. It is recommended for non-coastal areas or where humidity conditions are not high.

2. EPOXY-POLYURETHANE SYSTEM

Designed for severe or critical environments, in which the infrastructure or equipment and/or some other protected element is exposed to UV rays and an industrial atmosphere with high contamination (highly corrosive vapors).

This system is made up of an epoxy primer and Polyurethane (finish). Coatings designed for the protection of metal surfaces exposed to highly corrosive and chemical environments. Both coatings offer high adhesion, extraordinary chemical resistance, high abrasion resistance, resistance to UV rays, and impermeability, to improve the life of any metal surface or installation and reduce maintenance costs.

Graphenergy anticorrosive coating systems have many benefits, which include:

  • Higher performance than existing coating technologies on the market today.
  • Fewer applied coating layers are required and with higher anti-corrosion protection.
  • Coatings with greater adherence to the substrate.
  • Coatings with greater chemical resistance and high thermal resistance.
  • Coatings with greater impermeability and non-stick effect.

When a coating system is selected, the influence of the environment to which it will be exposed and the final appearance that is sought and some other considerations that the system must perform, and its maintenance must be taken into account.

On the other hand, another decisive factor that determines the selection of the first anticorrosive to be used and consequently the coating system is the physical state of the metal surface to be coated and/or the surface treatment or preparation that can be given.


Referencias

  1. Fengjuan Xiao, Chen Qian, et al., et al., Progress in Organic Coatings, 125, 79-88 (2018); doi.org/10.1016/j.porgcoat.2018.08.027
  2. Karolina Ollik and Marek Lieder. Review of the application of graphene-based coatings as anticorrosion layers. Coatings 2020, 10(9), 883. 2020.
  3. Zhang J., Kong, G., Li S., Le Y., Che C., Zhang S., Lai D., Liao X. Graphene-reinforced epoxy powder coating to achieve high performance wear and corrosion resistance. 20:1448-4160, 2020.

Graphene oxide: the new ally of primary coatings in corrosion protection

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Graphene oxide:

the new ally of primary coatings in corrosion protection

Corrosion is an electrochemical reaction that occurs when the metal reacts with the surrounding environment forming ferric oxide, causing the metal to lose its main characteristics of hardness and resistance. Oxygen, temperature, humidity, contaminants, gases, and the physicochemical characteristics of water are the main factors that affect the rate at which metals corrode.

One of the most widely used methods to control corrosion is the application of protective (primer) coatings to metal surfaces. The coating forms a barrier between the substrate (metal) and the surrounding medium, retarding the deterioration or oxidation of the metal. The coatings are polymer-based substances (paints), resistant to degradation, which are used to cover the material to be protected.

Nowadays, a wide variety of primers have been developed based on different types of resin, such as the alkyd and epoxy type. Efficiency is generally associated with an increase in cost. Unfortunately, most of these coatings or paints are not perfect barriers and eventually fail due to holes or micropores in the coating or the diffusion of oxygen and water through it (they are not completely waterproof). On the other hand, the coatings continue to have low thermal resistance and above all a limited chemical resistance.

Currently Energeia – Graphenemex®, a leading Mexican company in Latin America in the research and production of graphene materials for the development of industrial applications, through its Graphenergy line, has launched a range of primers and other nanotechnological coatings.

Graphenergy anticorrosive primers are coatings based on graphene oxide (GO), a new nanotechnological additive that provides multiple properties to coatings, including extraordinary corrosion protection and barrier technology (barrier effect). Graphene oxide creates pathways that are very tortuous, which prevents oxygen and water molecules from diffusing through the coating and eventually reaching the metal surface, providing protection against corrosion (Fig. 1). These primaries can act as mentioned, by (1) forming a barrier, which greatly prevents the penetration of oxygen and water molecules, or (2) the inhibition of the corrosion process, by increasing the electrical and ionic resistivity, cutting the corrosion cycle.

Fig. 1 Mechanism of anticorrosive protection of coatings based on polymers and graphene.

Among the anticorrosive primers that are currently for sale by Graphenergy, there are two: “Graphenergy anticorrosive alkyd primer” and “Graphenergy anticorrosive epoxy primer”, each one designed according to different needs and conditions.

A. Graphenergy anticorrosive alkyd primer.

Provides high anticorrosive protection, resistance to UV rays and provides extraordinary adherence to the substrate. Ideal for the protection of industrial infrastructure, for the application of ferrous surfaces, both for interiors and exteriors. It is recommended for non-coastal areas or where humidity conditions are not high.

B. Graphenergy anticorrosive epoxy primer.

In addition, this coating offers extraordinary chemical resistance, with high wear resistance, resistance to UV rays, impermeability and greater adhesion, in order to improve the useful life of any metal surface or installation and reduce maintenance costs.

Graphene coatings provide enhanced properties and many more benefits, including:

  • Higher performance than existing coating technologies on the market today.
  • Fewer applied coating layers are required and with higher anti-corrosion protection.
  • Zinc reduction in formulations can reduce the amount by up to 50%.
  • Primers with greater chemical resistance and high thermal resistance.
  • Coatings with greater impermeability and non-stick effect (dirt does not adhere to it). Graphene oxide creates a two-dimensional network on the surface of the coating, which does not allow the anchoring or diffusion of water molecules or chemical substances, which allows the development of coatings with a hydrophobic effect, resulting in coatings that are easier to clean (See Fig.2).
Fig. 2. Behavior of coatings without and with graphene oxide, after subjecting them to a chemical attack (corrosive solution) for more than two hours.
  • Improves adhesion to the substrate. The primers with graphene oxide increase their adherence by up to 50% with respect to the control (Fig. 3).
Fig. 3. Primer adhesion test with and without graphene oxide.
  • More flexible coatings. The incorporation of graphene oxide not only improves adhesion, but also allows flexibility to the coating, allowing it to have high resistance to bending or greater resistance to fracture (Fig. 4).
Fig.4. Flexibility test in primary without and with graphene oxide.

Referencias

  1. Chang, C.-H. et al. Novel Anticorrosion Coatings Prepared from Polyaniline/Graphene Composites. Carbon N. Y. 50, 5044–5051 (2012).
  2. Fengjuan Xiao, Chen Qian, et al., et al., Progress in Organic Coatings, 125, 79-88 (2018); doi.org/10.1016/j.porgcoat.2018.08.027
  3. Karolina Ollik and Marek Lieder. Review of the application of graphene-based coatings as anticorrosion layers. Coatings 2020, 10(9), 883. 2020.
  4. Zhang J., Kong, G., Li S., Le Y., Che C., Zhang S., Lai D., Liao X. Graphene-reinforced epoxy powder coating to achieve high performance wear and corrosion resistance. 20:1448-4160, 2020.
  5. Ghosh Tuhin and Karak Niranjan. Mechanically robust hydrophobic interpenetrating polymer network-based nanocomposites of hyperbranched polyurethane and polystyrene as an effective anticorrosive coating. New J. Chem., 2020, 44, 5980-5994.

Nanotechnology and corrosion protection: the era of graphene oxide

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Nanotechnology and corrosion protection:

the era of graphene oxide

Corrosion is defined as the gradual deterioration of metallic materials and their properties, and occurs when the metal reacts with the surrounding environment to form rust or another chemical compound. In general, atmospheric air, humidity, rain, and aqueous solutions (chemical products) are the environments that are most frequently associated with corrosion problems.

Nowadays, corrosion damage is one of the most important problems to face for many industries in the world. It is estimated that corrosion causes economic losses of 3.4% of world GDP (about 2.5 billion dollars per year). However, there are three industries whose corrosion impact is more frequent and riskier for their processes: the chemical industry, the shipbuilding industry and the construction industry.

In the chemical industry, the use of chemical products is paramount within its operations, so equipment and machinery are in direct and constant contact with chemical substances, increasing maintenance and/or repair costs, affecting the industry budget and their production. In the case of the naval industry, humidity and salt are the main factors that contribute to the corrosion process and, consequently, the deterioration and affectation of its facilities, ships, containers and even merchandise. On the other hand, in the construction industry, both the machinery and the construction areas themselves can be affected by corrosion due to their exposure to the environment. Corrosion causes the metallic assets to weaken, generating mechanical failures, putting the work at risk.

Anticorrosive coatings are regularly used for protection against corrosion, humidity and fouling of installations, machinery and equipment. At a commercial level, there is a wide variety of anticorrosive coatings based on different additives and resins, their efficiency is generally associated with an increase in cost. However, the coatings still have low thermal and corrosion resistance and especially limited chemical resistance.

Graphene is currently the most revolutionary nanotechnological additive in the coatings and paints industry. The incorporation of graphene as an additive in coatings produces coatings with extraordinary protection against corrosion. Graphene creates pathways that are very tortuous, preventing water and oxygen molecules and/or chemical agents from diffusing to the surface of metal-based materials, resulting in metal protection against oxidation and corrosion. corrosion (Fig. 1).

Figure 1. Schematic representation of the tortuous path for oxygen and water molecules in polymer coatings with clay and graphene.

Graphene coatings provide many performance and anti-corrosion benefits, including:

  • Higher performance than existing coating technologies on the market today.
  • Fewer applied coating layers are required for greater benefits
  • Zinc reduction in formulations
  • Chemical resistance


Graphene and graphene oxide-enhanced anticorrosive coatings will replace traditional zinc-based coatings, which have several drawbacks, such as short life, high content of volatile organic compounds (VOCs), slow curing, high cost, sedimentation in storage.


Currently Energeia – Graphenemex®, a leading Mexican company in Latin America in research and production of graphene materials for the development of industrial applications, through its Graphenergy line, has launched a wide range of nanotechnological coatings with graphene. These coatings offer high anticorrosive protection, extraordinary chemical resistance, high wear resistance, resistance to UV rays, impermeability and greater adherence, in order to improve the useful life of any surface or installation and reduce maintenance costs.

References

  1. Chang, C.-H. et al. Novel Anticorrosion Coatings Prepared from Polyaniline/Graphene Composites. Carbon N. Y. 50, 5044–5051 (2012).
  2. Fengjuan Xiao, Chen Qian, et al., et al., Progress in Organic Coatings, 125, 79-88 (2018); doi.org/10.1016/j.porgcoat.2018.08.027
  3. Chaudhry, A. U., Mittal, V. & Mishra, B. Inhibition and Promotion of Electrochemical Reactions by Graphene in Organic Coatings. RSC Adv. 5, 80365–80368 (2015).
  4. Zhen, Z. & Zhu, H. Graphene: Fabrication, Characterizations, Properties and Applications. Graphene (Academic Press, 2018).

Protection against bacteria, viruses and fungi with graphene coatings

Posted on | by Energeia Graphenemex

Protection against bacteria, viruses and fungi

with graphene coatings

In less than 20 years the world has faced a series of abnormal phenomena caused by highly infectious pathogens. The easy and rapid transmission of infections forces us to seek increasingly efficient strategies to strengthen health services, in addition to representing a radical change in our lifestyle, where extreme hygiene techniques are in first place of importance to avoid the spread and massive contagion inside and outside hospitals.

Viral diseases of greater impact.

  • 2002-2003. Severe acute respiratory syndrome (SARS-Cov).
  • 2012. Middle East Respiratory Syndrome (MERS-Cov).
  • 2014- 2016. Ebola.
  • 2019- 2022. SARS-Cov-2.

>6.5 million deaths.

Dangerous bacteria for human health:

  • Staphylococcus aureus.
  • Streptococcus pneumoniae.
  • Pseudomonas aeruginosa.
  • Haemophilus influenzae.
  • Helicobacter pylori.

Common fungi in the domestic environment:

  • Aspergillus spp.
  • Cladosporium spp.
  • Alternaria spp.
  • Acremonium spp.
  • Epiccocum spp.
  • Penicillium spp.
  • Stachybotrys spp.

Graphene as an adjuvant in infection control

In 2018, Energeia- Graphenemex® launched the antimicrobial Graphenergy line, made up of two specialized vinyl- and vinyl-acrylic-based coatings with graphene oxide, whose antimicrobial potential is 400 times higher than common products, helping to keep surfaces free of fungi and bacteria for a long time.

In vitro studies and in a relevant environment carried out by the Laboratory of Pathology, Biochemistry and Microbiology of the Faculty of Stomatology of the U.A.S.L.P., showed that surfaces protected with antimicrobial Graphenergy remain free of microorganisms for more than 6 months, without the need for additional chemicals. Figure 1.

Fig. 1. Results at 2, 4 and 6 months on the protection of antimicrobial Graphenergy compared to a control group (No Graphene Oxide).
Important: A clean surface is in the range of 1-10 CFU/cm2.

In 2022, the strategic alliance between the companies Energeia-Graphenemex® and Oxical® is preparing to launch a new 100% natural coating, without toxic compounds (VOCs), highly waterproof, breathable and highly antimicrobial, made from high-quality and purity lime modified with Graphene nanoparticles, under the ecological Graphenecal brand.

Its extraordinary antimicrobial capacity is not only a great aid in keeping spaces free of microorganisms, but also protects surfaces against biodeterioration, particularly those with high historical value. Figure 2.

Fig. 2. Graphene-free lime paint has a microbial biofilm on more than 90% of its surface. The area covered with organic Graphenecal remained free of contamination for more than 100 days of incubation. The antimicrobial effect of organic Graphenecal is highly effective, with a reduction of microorganisms of 7 Log10.

Is graphene nanotechnology safe?

Yes, Graphenergy and Graphenecal antimicrobial coatings are as safe as any conventional paint or coating. The graphene and graphene oxide nanoparticles contained in its formulations do not shed or release toxic substances into the environment.

“Not all microorganisms are dangerous, but it is better to keep them away”

How do graphene materials work?


  1. Physical barrier- High impermeability. Graphene materials are usually presented in millions of blocks composed of 1 to 10 nanometric sheets similar to a pack of cards, with multiple sinuous paths between each sheet that act as an external barrier that suppresses the entry of essential nutrients for microbial growth.

  2. Graphene and its derivatives can act as electron donors or acceptors, altering the respiratory chain of the microorganism or extracting its electrons. This imbalance in the form of a nano-circuit is so fast that it does not give the microorganism time to recover and, therefore, inactivates it before adhering to the surface.

  3. Structural damage. The edges of the nanomaterial sheets act like small knives that damage or break the cell membrane of the microorganism, altering its functioning and preventing its viability.

Do graphene materials have antiviral activity?

The antiviral effect of graphene materials seems not to be very different from that described against fungi and bacteria. The hypotheses are directed towards an interesting synergistic effect between impermeability, structural damage and electrostatic interactions due to the positive polarity of some viruses (SARS-Cov-2) and the negative polarity of graphene oxide, in addition to its great protein-anchoring capacity.

Energeia- Graphenemex®is the pioneer Mexican company in Latin America focused on the research and production of graphene materials for the development of applications at an industrial level. In addition to adding value to its products with the multifunctional properties of Graphene and its derivatives, the company also aims to create strategic alliances to support innovative developments with graphene nanotechnology.

References

  1. García-Contreras R, Guzmán Juárez H, López-Ramos D & Alvarez Gayosso C. Biological and physico-mechanical properties of poly (methyl methacrylate) enriched with graphene oxide as a potential biomaterial. J Oral Res 2021; 10(2):1-9. Doi:10.17126/joralres. 2021.019
  2. UM.D. Giulio, R. Zappacosta, S.D. Lodovico, E.D. Campli, G. Siani, A. Fontana, L. Cellini, Antimicrobial and antibiofilm eficacy of graphene oxide against chronic wound microorganisms. Antimicrob. Agents Chemother. 62(7), e00547-18 (2018). https://doi.org/10.1128/AAC.00547-18
  3. H.E. Karahan, C. Wiraja, C. Xu, J. Wei, Y. Wang, L. Wang, F. Liu, Y. Chen, Graphene materials in antimicrobial nanomedicine: current status and future perspectives. Adv. Healthc. Mater. 7(13), 1701406 (2018). https://doi.org/10.1002/ adhm.201701406
  4. Sydlik SA, Jhunjhunwala S, Webber MJ, Anderson DG, Langer R. In vivo compatibility of graphene oxide with differing oxidation states. ACS Nano. 2015. 9: 3866
  5. Yang K, Zhang S, Zhang G, Sun X, Lee ST, Liu Z. Graphene in mice: ultrahigh in vivo tumor uptake and efficient photothermal therapy. Nano Lett. 2010. 10: 3318.
  6. Bhattacharya K, Farcal LR, Fadeel B. Shifting identities of metal oxide nanoparticles: focus on inflammation. 2014. MRS Bull; 39: 970
  7. Huang PJ, Pautler R, Shanmugaraj J, Labbé G, Liu J. Inhibiting the VIM-2 metallo-β-lactamase by graphene oxide and carbon nanotubes. ACS Appl Mater Interfaces 2015; 7: 9898.
  8. Moghimi SM, Wibroe PP, Wu L, Farhangrazi ZS. Insidious pathogen-mimicking properties of nanoparticles in triggering the lectin pathway of the complement system. Eur J Nanomedicine. 2015; 7: 263.
  9. Bhattacharya K, Mukherjee SP., Gallud A., Burkert SC., Bistarelli S., Bellucci S., Bottini, M., Star A., Fadeel B. Biological interactions of carbon-based nanomaterials: From coronation to degradation. Nanomedicine: Nanotechnology, Biology, and Medicine. 2016. 12. 333