Category: Coatings

Tapping into Graphene’s Potential:

Posted on | by Energeia Graphenemex

Tapping into Graphene’s Potential:

Enhancing Coatings with Nanotechnology for Weather Resistance

Coatings are designed for decorative purposes and to protect surfaces, especially against corrosion and moisture. In a coating system (multilayer), the top or finishing layer plays a crucial role as it must provide a good appearance and protect the inner layers and the substrate against environmental factors such as sunlight, humidity, corrosion, chemical resistance, soiling, etc., throughout its lifespan.

Today, Polyurethane (PU) is considered one of the coatings with the best physical-chemical characteristics for finishing coating applications and for its weather resistance. However, its weather resistance decreases with exposure to ultraviolet light over long periods.

Sunlight is one of the main causes of damage to coatings. Damage ranges from loss of physical properties, powdering (chalking), cracking, peeling, discoloration, and color change, because of chemical photodegradation, migration, evaporation, and interaction of other components with the coating.

In recent years, various nanostructured materials such as titanium, zinc oxide, cerium, and iron oxide have been implemented to improve the weather resistance of polymeric coatings. The mechanism is based on their projection effect (both absorption and dispersion) of incident rays in the UV region. These materials can stabilize coatings against exterior exposure, possess photocatalytic activity that can destroy the organic binder material present in coatings, leading to modifying the surface of these nanostructured materials to eliminate or inhibit their photocatalytic activity, requiring more processes, time, and money.

Recently, graphene has attracted much attention as a new additive and material for producing coatings to enhance anticorrosive, antimicrobial, and weather-resistant properties, due to its special electronic structure that provides unique electrical, mechanical, and chemical properties. Graphene is a nanomaterial formed by one or more layers of carbon (formed by carbon atoms bonded hexagonally with a thickness of one carbon atom). This structure enables graphene-based materials to absorb photons in the UV region. This UV absorption capacity, as well as the absence of photocatalytic activity of graphene materials, allows introducing these materials as new additives for the photo-stabilization of polymeric coatings, i.e., with greater resistance to UV radiation

Currently, Energeia – Graphenemex®, is in constant development of nanotechnological coatings with better properties. Studies have been conducted on the influence of graphene oxide on the weathering behavior of PU coatings. To evaluate the performance of graphene oxide, a PU coating with graphene oxide (PU/GO) was compared with a PU coating containing a commercial organic UV absorber (PU/control).

Color change in a coating during exposure to weathering (sunlight) is the most important and rapid parameter to visually evaluate coating degradation. To evaluate, color change, samples coated with Polyurethane with and without graphene material were introduced into an accelerated weathering chamber (based on ASTM G154). According to the standard, a QUV weathering chamber model QUV/se was used to accelerate weathering conditions. Coated samples were cyclically exposed to UVA radiation (energy 0.89 W/m2) for 8 hours, followed by moisture condensation for 4 hours at 50 °C. The color of the coatings was evaluated before exposure to compare their initial color, and subsequently evaluated at different exposure times, this evaluation was performed until reaching an exposure time of 1200 hours.

The main component of color typically considered in weathering behavior is the total color change or Delta E (ΔE). Fig. 1 shows the ΔE, as the most comprehensive criterion of color changes, which is the sum of changes in all color components.

As can be seen, most of the color variations throughout the exposure time belong to the PU/control coating. The sample containing graphene oxide (PU/GO) at 251 hours of exposure time shows a lower color change compared to PU/control. With the increase in exposure time in the weathering chamber, color variations can be observed, but the sample with graphene oxide continues to show lower color changes, indicating that the incorporation of GO in Polyurethane provides more resistance and maintains its stability for longer exposure times to weathering.

Fig 1. Total color change (ΔE) versus exposure time for Polyurethane coatings with graphene oxide (PU/GO) and without graphene oxide (PU/control) during accelerated weathering test.

From a physical point of view, graphene oxide (GO) has higher transmittance in the visible region compared to graphene, which is more favorable for its use as a UV protector in finishing coatings. On the other hand, thanks to the high surface area of graphene materials, they can also provide excellent barrier effect properties and thus develop anticorrosive coatings with greater weather resistance.

Energeia – Graphenemex®, through its Graphenergy line, offers a wide range of nanotechnological coatings with graphene. These coatings offer high anticorrosive and antimicrobial protection. In addition to providing high wear resistance, UV resistance, impermeability, and extraordinary adhesion, with the aim of improving the life of any surface or installation and reducing maintenance costs.

References

  1. G. Wang, X. Shen, B. Wang, J. Yao, J. Park, Synthesis and characterisation of hydrophilic and organophilic graphene nanosheets, Carbon N. Y. 47 (no. 5) (2009) 1359–1364.
  2. B. Ramezanzadeh, M. Mohseni, H. Yari, S. Sabbaghian, A study of thermal-mechanical properties of an automotive coating exposed to natural and simulated bird droppings, J. Therm. Anal. Calorim. 102 (no. 1) (2010).
  3. N. Rajagopalan, A.S. Khanna, Effect of Methyltrimethoxy Silane Modification on Yellowing of Epoxy Coating on UV (B) Exposure vol. 2014, (2014).
  4. M. Hasani, M. Mahdavian, H. Yari⁎, B. Ramezanzadeh. Versatile protection of exterior coatings by the aid of graphene oxide nanosheets; comparison with conventional UV absorbers. 2017.
  5. S.M. Mirabedini, M. Sabzi, J. Zohuriaan-Mehr, M. Atai, M. Behzadnasab,
  6. Weathering performance of the polyurethane nanocomposite coatings containing silane treated TiO2 nanoparticles, Appl. Surf. Sci. 257 (no. 9) (2011) 4196–4203.
  7. N.S. Allen, M. Edge, A. Ortega, C.M. Liauw, J. Stratton, R.B. McIntyre, Behaviour of nanoparticle (ultrafine) titanium dioxide pigments and stabilisers on the photooxidative stability of water based acrylic and isocyanate based acrylic coatings, Polym. Degrad. Stab. 78 (no. 3) (2002) 467–478.
  8. Effect of Silane Modified Nano ZnO on UV Degradation of Polyurethane Coatings. vol. 79, (2015), pp. 68–74.
  9. M. Rashvand, Z. Ranjbar, S. Rastegar, Nano zinc oxide as a UV-stabilizer for aromatic polyurethane coatings, Prog. Org. Coatings 71 (4) (Aug. 2011) 362–368.

Defying the flames

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Defying the flames:

The triumph of graphene oxide in the creation of fire-fighting coatings

The inclusion of Graphene Oxide (GO) in coatings demonstrates effectiveness in inhibiting flammability, providing a fire-resistant barrier. Benefits include anti-corrosion protection, antimicrobial properties and increased adhesion to substrates. This advance highlights Energeia-Graphenemex’s innovation in the production of fireproof coatings, positioning itself as a leader in the research and application of high-quality graphene materials.

Coatings are used in various sectors, at an industrial level the use of coatings are focused on protection against corrosion, while at a commercial level they are used for infrastructure maintenance and for decorative purposes. Today, the coatings industry continues to constantly research the development of improved coatings, with antimicrobial, non-stick properties, and greater resistance to chemical attack and weathering. However, at a commercial level there are few developments focused on fireproof coatings (flame retardant) for fire protection in infrastructure.

Traditional fireproof coatings are cementitious coatings, based on Portland cement, magnesium oxychloride cement, vermiculite, gypsum and other minerals. In addition, they contain fibrous fillers, binders, supplements and additives that control density and rheology, these materials are generally mixed with water on site and applied by spraying some construction or can be applied to a flammable substrate by using a roller, in thicknesses of half an inch or more. However, due to their weight, thickness and poor aesthetics, they limit architectural design.

In coatings and paint industry, there is a wide variety of coatings based on different types of resins (polymers) and additives. Due to their nature, most of these coatings are flammable and combustible materials. That is, they are materials that can catch fire when exposed to fire, suffering degradation and the release of heat to subsequently initiate the spread of the flame, releasing smoke and toxic gases, being a danger to the safety of human life and property. On the other hand, polymer-based fireproof coatings use conventional additives based on halogens (bromine and chlorine), as well as phosphorus, melamine and inorganic compounds, to improve the fire resistance of the coatings, however, these materials are toxic to humans and the environment.

In recent years, Energeia-Graphenemex has focused on the production of graphene materials. Graphene is the most revolutionary nanotechnological additive for the coatings and paints industry, as it allows the development of coatings with extraordinary anti-corrosion protection, coatings with antimicrobial properties, coatings with better adhesion to substrates and greater resistance to UV radiation. In this sense, graphene oxide (GO) has been shown to be a new additive that helps inhibit or reduce the flammability of coatings, to produce effective fireproof coatings.

Its efficiency is associated with the fact that GO has a strong barrier effect, high thermal stability and great surface absorption capacity that are favorable for effectively reducing heat and mass transfer.

The incorporation of GO in coatings can improve flame resistance, by inhibiting the two key terms: heat and fuel. That is, it can function as a flame retardant in the following ways:

• GO possesses a unique two-dimensional layer structure and can promote the formation of a dense continuous layer of carbon during the combustion process (see Fig. 1). Carbon can act as a physical barrier to prevent heat transfer from the heat source and delay the escape of products (pyrolysis) from the coating.

• Because GO has a large surface area, it can effectively adsorb flammable volatile organic compounds or hinder their release and diffusion during combustion.

• The presence of oxygenated groups in the GO structure means that, during the combustion of the coating, the oxygen-containing groups in GO can undergo decomposition and dehydration at low temperature, thus absorbing heat and cooling the polymeric substrate during combustion. Meanwhile, gases generated by dehydration can dilute the oxygen concentration around the ignition periphery, decreasing the risk of fire spread.

In summary, the incorporation of GO in coatings can provide fire protection, because they can release water and provide thermal insulation effects.

Graphene-based flame-retardant coatings are designed to retard ignition and burn rate, and must provide a fire-resistant barrier.

Energeia – Graphenemex®, Mexican company, leader in Latin America in research and production of graphene materials for the development of industrial applications. It has extensive experience in the large-scale production of graphene oxide (GO) and has high-quality graphene materials for sale for use in different industries.

Fig.1 Flame retardancy test of coatings (Method based on UL-94 classification), where;
a) coating without GO and b) Coating with GO.

References

  1. Sachin Sharma Ashok Kumar, Shahid Bashir, K. Ramesh, S. Ramesh, Progress in Organic Coatings, 154, (2021)
  2. Weil, Edward. D. Fire-Protective and Flame-Retardant Coatings – A State-of-the-Art Review. Journal of Fire Sciences, 29(3), 259–296.
  3. Lipiäinen, H., Chen, Q., Larismaa, J., & Hannula, S. P. (2016). The Effect of Fire Retardants on the Fire Resistance of Unsaturated Polyester Resin Coating. Key Engineering Materials, 674, 277–282.
  4. Md Julker Nine, Dusan Losic. Mahmood Aliofkhazraei, Nasar Ali, Mircea Chipara, Nadhira Bensaada Laidani, Jeff Th.M. De Hosson, Handbook of Modern Coating Technologies, Elsevier, 2021, Pages 453-492.

Graphene Oxide, the nanomaterial that will reduce the impact of corrosion

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Graphene Oxide

the nanomaterial that will reduce the impact of corrosion

What is corrosion?

The term corrosion refers to the destruction of a material because of its chemical or electrochemical interactions with the surrounding medium. The importance of its prevention and/or control is due to the fact that, being a natural phenomenon, once started it is practically impossible to stop. Therefore, an uncontrolled evolution will invariably compromise the integrity and useful life of the materials, generating the industry involved direct and indirect expenses due to loss of product, stoppage of activities due to maintenance until the replacement of machinery or structures.

“Economic losses caused by corrosion exceed 3.4% of global GDP”

Microbiologically influenced corrosion

Microbiologically influenced corrosion (MIC) can be defined as the electrochemical process in which microorganisms such as algae, fungi and bacteria initiate, facilitate, or accelerate a corrosion reaction, generally located in the form of cracks. or pitting on both metal and concrete surfaces. Although corrosion involves various variables, it is estimated that MIC participates in 20 to 40% of all corrosion failures, particularly in hydraulic and oil infrastructure, with costs close to 2 billion dollars annually.

Why do you start the MIC?

The presence of humidity in any environment is the ideal habitat for the growth of numerous communities of microorganisms that, combined with optimal conditions of temperature, pH, nutrient flow, etc., promotes their adhesion and growth on surfaces, forming a biofilm that is not removed, it grows into a hardened, obstructive biomass within which sulfate-reducing bacteria, acid-producing bacteria, iron-reducing bacteria, and gel-forming bacteria promote corrosion or MIC through destructive electrochemical reactions of the surfaces.

How do you combat it?

There are three most common methods to try to combat MIC, the first is mechanical cleaning of surfaces to remove biofilms, ideally in incipient stages, however, it is not always possible to access all exposed areas, making their efficiency difficult. The second is the use of biocidal agents that, in addition to being expensive, most may not be friendly to human health and the environment. Finally, and perhaps the most suitable method is the placement of external barriers in the form of coatings or polymeric films to prevent direct contact of the metal or concrete structures with the aggressive medium.

Corrosion control in concrete

The options available to protect concrete against corrosion from its fresh state are the additions of pozzolanic materials, fly ash, blast furnace slag, sulfate-free aggregates, polymer fibers, use of sulfate-resistant cement or modified with nanoparticles such as nanotubes and carbon nanofibers, silica nanoparticles, alumina or titanium dioxide. For protection in the hardened state, it is common to apply physical barriers such as anti-corrosion coatings or polymeric films and, for the protection of metal structures, in addition to anti-corrosion coatings, you can use galvanized, tinned structures or the placement of magnesium sacrificial anodes. However, it is considered that, due to the natural porosity of concrete, there are no totally efficient methods that attack the problem of corrosion towards the interior of structures.

Corrosion in concrete can occur due to carbonation, ingress of chlorides and sulfates or due to microbiological attack. When the concrete has reinforcing steel and is attacked by corrosion, oxide can grow 2 to 4 times the volume of the original steel, causing loss of adhesion of concrete and put the resistance of the material at risk. Furthermore, the porosity of the concrete, in addition to allowing the passage of moisture for the entry of aggressive ions, also offers millions of ideal niches for the retention of microorganisms and for the subsequent formation of MIC-initiating biofilms, not only because they favor their anchoring, but because they make their removal difficult and promote the advancement of corrosion.

“It is expected that by 2032 the corrosion inhibitors market will amount to 12.5 billion, and in 2022 this figure will be around 8.3 billion.”

Graphene and graphene oxide are multifunctional carbon nanomaterials with extraordinary properties that, when incorporated as a nanofiller in other compounds such as coatings, plastics or cement, have the ability to molecularly organize their structure in such a way that they improve their resistance to chemical, physical and microbiological attacks. Among their particularities is that they are inert nanostructures, that is, they are stable, they do not react with other materials and they do not suffer oxidation or corrosion. They are extremely thin and light, but at the same time, very resistant and flexible. They are impermeable even to gases and have highly efficient antimicrobial mechanisms.

Below is a summary of some of the most notable research on the use of graphene as an alternative against microbiologically influenced corrosion (MIC):

2015- The Department of Materials Science and Engineering at Rensselaer Polytechnic Institute, New York, USA, modified polyurethane coatings with graphene identifying 10 times greater protection against MIC compared to unmodified polyurethane coatings.

2017- The Nanobiomaterials laboratory of the Federico Santa María Technical University, Valparaíso, Chile, evaluated the direct effect of graphene placed on nickel substrates and its interaction with bacteria that cause corrosion. The results showed an impermeable barrier generated by graphene that blocked the interaction between bacteria and the metal, but without a bactericidal effect.

2021- The Department of Civil and Environmental Engineering, South Dakota School of Mines and Technology, USA, reported that multiple layers of graphene restricted MIC attack on copper and nickel surfaces 10 times more.

2021– The School of Engineering at the University of Glasgow, Scotland, examined the deterioration of graphene oxide (GO)-modified cement pastes exposed to acidic environments. The results demonstrated that the presence of GO reduces the loss of mass in the concrete due to these attacks, recognizing it as a potential additive to modify the microstructure and useful life of concrete in the face of aggressive environments such as those present in chemical product warehouses to systems. of wastewater.

Energeia Fusion (Graphenemex®), the leading Mexican company in Latin America in the production of graphene materials, after a long journey of research, in 2018 launched the Graphenergy Line on the market, which includes a series of anticorrosive and antimicrobial coatings with graphene nanotechnology and the first additive for concrete with graphene oxide in the world, whose individual or combined use promises great benefits against corrosion.

Graphenergy Construction is a water-based additive with graphene oxide designed to improve the quality of cement structures in terms of mechanical resistance and durability. The added value that graphene oxide offers to concrete in the fight against MIC from the outside to the inside is the result of a series of events that begin by favoring the hydration of the cement, acting as water reservoirs and as a platform for the growth of crystals. of C-S-H and to dissipate the heat of hydration; improves the interfacial transition zones between the cement paste and the aggregates, helping to reduce the size and volume of the pores, this in turn favors an increase in mechanical resistance, reduces permeability, increases its resistivity, that is, reduces the transfer of electrical charges into the interior of the concrete, delaying the onset of corrosion and, finally, modifying the electrostatic charges and the wettability of the surfaces, making the formation of biofilms that cause MIC difficult.

Graphenergy coatings formulated with graphene oxide offer great resistance against corrosion in coastal and non-coastal areas, as well as excellent antimicrobial protection without biocidal mechanisms, since their effect consists of preventing the adhesion of microorganisms to surfaces. In addition, its impermeability, resistance to abrasion and resistance against the intense effects of the elements increase its useful life and, therefore, substantially reduce the maintenance costs of both metal and concrete structures.

Drafting:  EF/DH

References

  1. The Many Faces of Graphene as Protection Barrier. Performance under Microbial Corrosion and Ni Allergy Conditions. Materials 2017, 10, 1406;
  2. Effect of graphene oxide on the deterioration of cement pastes exposed to citric and sulfuric acids. Cement and Concrete Composites, 2021, 124, 104252;
  3. Superiority of Graphene over Polymer Coatings for Prevention of Microbially Induced Corrosion. Scientific Reports, 2015, 5:13858;
  4. Atomic Layers of Graphene for Microbial Corrosion PreventionACS Nano 2021, 15, 1, 447;
  5. Microbiologically induced corrosion of concrete in sewer structures: A review of the mechanisms and phenomena. Construction and Building Materials. 2020, 239, 117813;
  6. Microbiologically Induced Corrosion of Concrete and Protective Coatings in Gravity Sewers. Chinese Journal of Chemical Engineering, 2012, 20(3) 433;
  7. In situ Linkage of Fungal and Bacterial Proliferation to Microbiologically Influenced Corrosion in B20 Biodiesel Storage Tanks. Front. Microbiol. 2020, 11;
  8. Chapter 1 – Failure of the metallic structures due to microbiologically induced corrosion and the techniques for protection. Handbook of Materials Failure Analysis. With Case Studies from the Construction Industries. 2018, 1;
  9. Maleic anhydride-functionalized graphene nanofillers render epoxy coatings highly resistant to corrosion and microbial attack. Carbon, 2020, 159, 586;
  10. Gerhardus Koch, Cost of corrosion, In Woodhead Publishing Series in Energy, Trends in Oil and Gas Corrosion Research and Technologies, Woodhead Publishing, 2017;
  11. https://www.futuremarketinsights.com/reports/corrosion-inhibitors-market.
  12. http://www.imcyc.com/revistacyt/oct11/artingenieria.html

Graphene in protection against electromagnetic radiation

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Graphene in protection

against electromagnetic radiation

The development of communication technology together with electronic devices has generated great concern regarding the electromagnetic radiation emitted by these technologies.

Electromagnetic radiation is a type of electromagnetic field, that is, a combination of oscillating electric and magnetic fields, which propagates through space carrying energy from one place to another. Electromagnetic radiation can manifest itself in various ways, such as radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays or gamma rays and correspond to different wavelengths, ranging from kilometers (radio waves) to the order of picometers (gamma rays). The full range of wavelengths is what is called the electromagnetic spectrum (Figure 1.).

Figure 1. Electromagnetic spectrum.

Electromagnetic radiation can be high frequency (radiation from mobile and wireless telephones, radio frequencies, TV waves, microwaves, radar, satellite signals, Wi-Fi, Bluetooth) and low frequency (fields generated by cables or electrical consumers).

Heat and electromagnetic radiation (EM radiation) are unavoidable by-products in electronic devices, especially those that operate at high frequencies. As electronic devices get smaller, they operate at higher and higher frequencies, generating even more heat and electromagnetic waves.

High frequency electromagnetic radiation not only degrades the devices themselves (producing heat), but also tends to interfere with neighboring electronic devices and most importantly, it has an adverse effect on human health as it can cause many diseases, such as leukemia, miscarriages, and brain cancer.

Therefore, the blocking or protection (shielding) against electromagnetic radiation could be one of the solutions to minimize health risks and for the protection of electronic equipment and/or devices. Metals are natural electromagnetic blocking materials, capable of reflecting electromagnetic waves due to their free electrons, which explains their high electrical conductivity and low penetration depth. However, their heavy weight, cost and the susceptibility of metals to corrosion make their use limited if not impossible.

The use of conductive coatings or paints to block electromagnetic radiation is the most viable option to solve the problem. Graphene is currently the most revolutionary nanotechnological additive in the coatings industry. Because graphene has extraordinary properties, which include high electrical conductivity, high thermal conductivity, and mechanical resistance. In addition, it possesses other distinctive properties, including gas impermeability, chemical resistance, antibacterial potential, and large surface area.

The electrical conduction capacity and thermal conductivity of graphene can be exploited in the formulation of shielding coatings against EM radiation, since graphene forms a continuous network along the surface of the coating, creating homogeneous films that block radiation. electromagnetic radiation while dissipating excess heat. In recent studies, it has been reported that the incorporation of carbon-based nanostructures, such as graphene in coatings or paints, allows the development of coatings with high electrical conductivity for shielding or protection against electromagnetic interference (EMI). The way to act with respect to high frequency electromagnetic waves is by refraction. Electromagnetic waves will bounce (reflect) off the treated surface similar to the effect of a mirror with respect to light (See Fig. 2). The barrier-effect in the propagation could be attributed to the contribution coming from the reflection capacity, the absorption and multiple internal reflections. The shielding efficiency increases with the addition of a higher concentration of graphene in the polymeric matrix of the coating. These graphene coatings can block more than 99.98% of high-frequency electromagnetic radiation.

Figure 2. Percentage of Reflection, absorption and transmission of pristine epoxy (a) and epoxy with graphene (b).
Taken from Adv. Electron. Mater. 2019, 5. 1800558

These coatings against electromagnetic radiation can act for both high frequency and low frequency, with an excellent quality of attenuation (decrease in intensity of signals or electric waves) of up to 38 dB, with one hand, and 47 dB if applied. two hands.

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 line, is constantly researching and developing new multifunctional coatings and currently has for sale a wide range of nanotechnological coatings with graphene. Shielding coatings against electromagnetic radiation are currently being developed and evaluated. Coatings with high electrical conductivity, to reduce high and low frequency electrical fields respectively. These coatings will also offer anticorrosive and antimicrobial protection. In addition, to provide high resistance to wear, resistance to UV rays, impermeability and extraordinary adhesion.

Referencias

  1. Suneel Kumar Srivastava, Kunal Manna, Recent advancements in the electromagnetic interference shielding performance of nanostructured materials and their nanocomposites: a review, Journal of Materials Chemistry A, 10.1039/D1TA09522F, 10, 14, (7431-7496), (2022).
  2. Kargar, F., Barani, Z., Balinskiy, M., Magana, A. S., Lewis, J. S., Balandin, A. A., Adv. Electron. Mater. 2019, 5, 1800558.
  3. Seul Ki Hong et al 2012 Nanotechnology 23 455704.
  4. Lekshmi Omana, Anoop Chandran*, Reenu Elizabeth John, Runcy Wilson. Recent Advances in Polymer Nanocomposites for Electromagnetic Interference Shielding: A Review. Omega 2022, 7, 30, 25921–25947

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

Posted on | by Energeia Graphenemex

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

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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

Graphene oxide: a promising alternative in nanotechnology

Posted on | by Energeia Graphenemex

Graphene oxide:

a promising alternative in nanotechnology

Since graphene was isolated for the first time in 2004 by the Manchester group, this nanomaterial has proven to be the most revolutionary for the development of new applications at an industrial level.

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, made up of hexagonally bonded carbon atoms and a thickness of one carbon atom.

Currently there are different methods of graphene production, these can be classified into two methods, according to their origin, the “bottom-up” method and the “top down” method. The “bottom-Up” method consists in the creation of graphene structures through building blocks (atoms, molecules), for example, by Chemical Vapor Deposition (CVD); and the “top down” method involves the production of graphene from the oxidation of graphite. Graphite is made up of sheets of graphene that are stacked on top of each other. The following diagram represents the process for obtaining graphene from the oxidation of graphite.

Schematic diagram of the process for obtaining GO, through the oxidation of graphite.

The graphite oxidation process begins with the addition of graphite in sulfuric acid (H2SO4), with constant mechanical stirring. Subsequently, potassium permanganate (KMnO4) is slowly added, producing a chemical reaction that allows the graphite (graphene sheets stacked on top of each other) to be chemically modified in its structure. When KMnO4 reacts with H2SO4, it forms manganese oxide VII (Mn2O7), which is a very selective oxidizing agent on double bond aromatic compounds, such as graphite. The oxidizing agent molecularly attacks the structure of each graphene sheet in the graphite, grafting oxygenated functional groups (with oxygen), such as epoxide groups (C-O-C) and hydroxyl groups (-OH), on each sheet, and carboxyl groups (-COOH, CO2H ) on the edges of each sheet, obtaining graphite oxide and graphene oxide (GO), see Figure 1.

Figure 1. Structure of graphene oxide

The incorporation of oxygenated functional groups allows a material such as graphite, which is highly hydrophobic (which repels water) and a good electrical conductor, to become graphite oxide and graphene oxide (GO), highly hydrophilic materials, that is, they mix and disperse easily with water (See Figure 2). GO is chemically similar to graphite oxide, but structurally differs in the arrangement and number of stacked sheets.

Figure 2. (a and b) Behavior of graphite and graphene oxide (GO) in water, c) GO sheet, Transmission Electron Microscopy (TEM).

The GO can be defined as a single exfoliated graphene sheet or stack of few sheets (3-4) that is functionalized with different oxygenated groups. Among its main characteristics is that it is hydrophilic, insulating and hygroscopic (absorbs moisture). On the other hand, graphene oxide sheets possess a large surface area and exhibit high mechanical strength and flexibility.

Applications

Graphene oxide has attracted great interest in various fields of science and technology, due to its remarkable mechanical, chemical, and thermal properties, among others. So numerous investigations began, to take advantage of the properties of graphene oxide.

In 2011, the first investigations of the use of GO as a precursor in the large-scale production of graphene emerged, for use as filler/reinforcement material/in polymeric matrices, such as high-density polyethylene (HDPE) and low-density polyethylene (HDPE). density (LDPE).

By 2014, GO was considered feasible for use as a flame retardant agent. Research is still ongoing to functionalize it with different polymeric materials.

In 2017, the first reports of the manufacture of GO-based membranes began, since it is impermeable to gases and liquids, showing its ability to filter small particles, organic molecules and even its use for seawater desalination.

In 2018, Energeia-Graphenemex started research on graphene oxide as a new additive for the production of anticorrosive and antimicrobial coatings. By 2019, studies of graphene oxide in coatings with antibacterial behavior increased, associated with the fact that GO is capable of penetrating the cell membrane of bacteria, producing oxidative stress and inhibiting their reproduction.

In particular, the functionalization of GO allows it to be applicable in biological systems, development of biosensors for the identification of specific molecules, drug delivery systems, among others.

Energeia – Graphenemex®, a leading Mexican company in Latin America in research and production of graphene materials for the development of industrial applications. It has extensive experience in the production of graphene oxide (GO) on a large scale, with different degrees of oxidation and high quality for use in different applications and industries. Currently, it uses graphene oxide in the production of concrete additives and anticorrosive and antimicrobial coatings that are marketed under the Graphenergy brand.

References

  1. M. Fang, K. Wang, H. Lu, Y. Yang y S. Nutt, «Covalent polymer functionalization of graphene nanosheets and mechanical properties of composites,» Journal of Materials Chemistry, vol. 19, pp. 7098-7105, 2009.
  2. B. Dittrich, K.-a. Wartig, R. Mülhaupt y B. Schartel, «Flame-Retardancy Properties of Intumescent Ammonium Poly(Phosphate) and Mineral Filler Magnesium Hydroxide in Combination with Graphene,» Polymers, vol. 6, pp. 2875-2895, 2014.
  3. Y.-j. Wan, L.-x. Gong, L.-c. Tang, L.-b. Wu y J.-x. Jiang, «Mechanical properties of epoxy composites filled with silane-functionalized graphene oxide,» COMPOSITES PART A, vol. 64, pp. 79-89, 2014.
  4. J. Wang, C. Xu, H. Hu, L. Wan, R. Chen, H. Zheng, F. Liu, M. Zhang, X. Shang y X. Wang, «Synthesis , mechanical , and barrier properties of LDPE / Graphene nanocomposites using vinyl triethoxysilane as a coupling agent,» J. Nanopart Res, vol. 13, pp. 869-878, 2011.