Tag: impermeability

Graphene in protection against electromagnetic radiation

Posted on | by Energeia Graphenemex

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 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-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

Graphene: a revolution in the paper industry

Posted on | by Energeia Graphenemex

Graphene:

a revolution in the paper industry


The paper industry represents a very broad and versatile market, in fact and despite the challenges it faces due to the impact of digital media and its competition with plastic, its world production continues to be considerable, exceeding 400 million tons distributed in products for containers and packaging, for hygienic and sanitary use, as well as paper for printing, writing and the press.

“It is estimated that by the end of 2022 cardboard will represent two thirds of world paper production”

On the other hand, the continuous need for innovation as well as the search for solutions to the problems inherent in these products, such as their easy contamination and permeability, have made nanotechnology remain an important tool with the use of different nanomaterials such as nano- cellulose crystals and nanofibers, nanoparticles of silicon oxide (SiO2), titanium dioxide (TiO2), zinc dioxide (ZrO2) and recently graphene materials such as graphene and graphene oxide (GO) 1 with the aim of design nano-scale building blocks to obtain denser and less porous networks that, in addition to improving the quality of the final product, also diversify its use.

“Cellulose, in addition to being one of the most abundant natural polymers on earth, is also the main raw material for the paper industry. Graphene is obtained from graphite, a very abundant carbon mineral in Mexico”

How do graphene materials benefit the paper industry?


When talking about graphene, the main points of reference are its resistance, impermeability, flexibility, conductivity, lightness, biocompatibility, etc., all in a single material. Given this, it is important to understand that the behavior of graphene materials will depend, among other things, on the type of graphene, functionalization and concentration, but also on the processes involved in each industry and the nature of the materials with which it will be combined to transfer its properties and therefore there is no exact formula for each usage target, for example:


Mechanical strength- In the case of cellulose films, the presence of as little as 0.5% GO can significantly improve tensile strength, elongation at break and fracture energy by 78%, 172% and 397%, respectively; useful for its application in high performance bioplastic films2.


Antimicrobial protection- Among the benefits of interest to the paper industry are its biocompatibility, its physical barrier properties and its antimicrobial activity. For example, a study that prepared a paper coating with 0.05% GO reduced the growth rate of bacteria such as E. coli and S. aureus by 73% and 53%, respectively3,4. This is because GO helps limit microbial adhesion, replication and penetration.

Protection against UV radiation- According to another report, the use of 2% GO in cellulose films blocks UVA and UVB radiation by 66.7% and 54.2% respectively, without affecting the transmission of visible light, an interesting property for the design of protection and packaging materials.5


Barrier properties- Graphene materials present nano-channels between their sheets that represent a tortuous path for the passage of large molecules and, therefore, it is widely investigated both for its great impermeability against liquids and gases, but also for its potential benefits for the decontamination, purification and even desalination of seawater. Research carried out on cellulose acetate (CA) membranes for desalination described that the use of 1% GO improves morphology, hydrophilicity, porosity, roughness, mechanical resistance, thermal stability and, therefore, its operating efficiency, as well as it has happened with other types of membranes such as polysulfone, in which a concentration of 0.2% GO can be enough to improve their performance by up to 72%, in terms of water flow and salt rejection in tests with sodium sulfate. sodium6,7. The foregoing is not only reflected in the efficiency of filtration and/or desalination, but also the optimization of maintenance resources and energy consumption of said systems.


Energeia- Graphenemex®, the leading company in Latin America in the design and development of applications with graphene materials, continuously works to solve the obstacles that graphene faces to reach the market and, through strategic alliances with other industries, seeks to make this technology available to the industry for solving various problems.


References

  1. Trache, D., Thakur, V. K., & Boukherroub, R. 2020., Cellulose nanocrystals/graphene hybrids—a promising new class of materials for advanced applications. Nanomaterials, 10(8), 1523.
  2. M. Akhtari, M. Dehghani-Firouzabadi, M. Aliabadi, M. Arefkhani. Effect of graphene oxide nanoparticle coatings on the strength of packaging paper and its barrier and antibacterial properties. 2019., Bois et Forêts des Tropiques. 342, 69.
  3. W. Hu, Ch. Peng, W. Luo, M. Lv, X. Li, D. Li, Q. Huang, and Ch. Fan. Graphene-Based Antibacterial Paper. 2010. ACS Nano, 4, 7, 4317–4323
  4. X. Liu, T. Zhang, K. Pang, Y. Duan and J. Zhang. Graphene oxide/cellulose composite films with enhanced UV-shielding and mechanical properties prepared in NaOH/urea aqueous solution. 2016., RSC Adv., 6, 73358
  5. Zhang, X. F., Song, L., Wang, Z., Wang, Y., Wan, L., & Yao, J. 2020., Highly transparent graphene oxide/cellulose composite film bearing ultraviolet shielding property. International journal of biological macromolecules, 145, 663.
  6. S. M. Ghaseminezhad, M. Barikani, M. Salehirad.  Development of graphene oxide-cellulose acetate nanocomposite reverse osmosis membrane for seawater desalination. Composites Part B: Engineering. 2019., 161, 15, 320.
  7. B.M. Ganesh, Arun M. Isloor, A.F.Ismail., Enhanced hydrophilicity and salt rejection study of graphene oxide-polysulfone mixed matrix membrane. 2013., Desalination., 313, 199.

Graphene and its impact on the packaging industry

Posted on | by Energeia Graphenemex

Graphene

and its impact on the packaging industry

According to data from the World Bank, every year in Mexico 24 million tons of food are wasted. This means that 34% of the country’s production is not only NOT consumed, but also generates an average expense of 491 billion pesos.

This impact is not only economic, but it is a problem that extends to the social sphere, due to the well-known food crisis and to the environment, due to the high water requirements for food production processes that will not be used and whose decomposition will contribute considerable CO2 emissions that contribute to global warming.

According to the Food and Agriculture Organization of the United Nations, the loss and food waste exceeds 1,300 million tons per year.

Within this multifactorial problem, the container and packaging industry, also known as “packing”, is a crucial actor considering that there are unavoidable conditions such as temperature, humidity, lighting, oxygen and numerous handling practices throughout the entire supply chain. production of food, which affect its quality, shelf life and acceptability by consumers.

In the search for solutions to improve the quality of packing products and, consequently, their content, nanotechnology has been a great ally. For example, to avoid microbial contamination, nanoparticles of silver, titanium dioxide, copper oxide, carbon nanotubes or magnesium oxide are used; to improve the mechanical or barrier properties, it is common to use nanoparticles of silicate, clay, polyamide, iron or iron oxides, cellulose nanofibers and for other needs there are nanoparticles of tungsten, molybdenum, barium sulfate, barium titanate , chitosan, zeolites, activated carbon, etc.

Graphene nanoparticles are mainly made up of carbon, like graphite and diamond, but with multifunctional characteristics. This means that they do not have a single function, but rather, unlike other nanoparticles, Graphene, due to its extraordinary physical and chemical properties, can be used for different purposes, for example, to design lighter and more resistant products, with greater impermeability against liquids and gases, in addition to protecting against microbial contamination and against UV radiation, among other properties that substantially improve the performance of the compounds with which it is combined.

“Graphene has crossed the limits of laboratories to reach commercial applications to combat the main enemies of food”, these are some examples of what is being developed for the Packing industry:

Tetra Pak
The Swedish company Tetra Pak, leader in research and development in the packaging sector, through the European Graphene Flagship project, studies the use of Graphene for the manufacture of products with low environmental impact to reduce the carbon footprint, improve the performance of materials, add properties and optimize recyclability.

Applynano
The Spanish company Applynano uses nanomaterials, including graphene oxide, to promote the durability and recyclability of plastics, as well as to improve antimicrobial, thermal, and electrical properties, among others.

Plastic Technology Center (Andaltec)
The Technological Center of Plastic (Andaltec) within the European project Grafood, had the initiative to use derivatives of Graphene for the development of active packaging to increase the shelf life of food and reduce food waste.

Energeia – Graphenemex®
The Mexican company Energeia – Graphenemex®, through the polymer division Graphenergy Advanced Graphenic Solutions, promotes the use of Graphene and its derivatives as nano-reinforcement of plastic for different industries. Among the benefits it offers for the packing industry are mechanical resistance and resistance to degradation by UV radiation, greater barrier effect and interesting antimicrobial properties, highly promising for prolonging the life of products and their contents. Likewise, in addition to adding value to its developments with the multifunctional properties of Graphene and its derivatives, the company also aims to support other innovation projects with graphene nanotechnology, while seeking to collaborate with the circular economy to improve the quality of new and recycled plastic materials, to reduce the consumption of single-use products.