Performance of Reinforced Concrete with Polymeric Macrofibers and Graphene Oxide:
Results Report Graphenergy® Construction
Polymeric macrofibers are small filaments of strong synthetic material dispersed throughout the concrete mix to reinforce it from within. Their random distribution creates a discontinuous and homogeneous three-dimensional reinforcement effect that enhances the concrete’s toughness and ductility at every point of the structure.
The materials commonly used for the manufacture of this type of product include polypropylene, polyethylene, polyester, or nylon in different gauges or dimensions. These are highly effective for the reinforcement of pavements and roads, slabs, precast elements, shotcrete, and in some cases, may even substitute welded wire mesh. Given the wide variety of products, it is important to seek proper advice before use and to consider that macrofibers do not always increase the compressive or flexural strength of concrete, as they are mainly used for microcrack control. Therefore, they are not intended as a full replacement for structural reinforcement such as steel.
The Mexican company Energeia–Graphenemex®, through its polymer division, integrated the multifunctionality of graphene oxide to launch Graphenergy® Polymeric Macrofibers in order to enhance concrete performance under intense stresses.
Graphenergy® polymeric macrofibers represent an innovation in secondary three-dimensional reinforcement for concrete thanks to the integration of polymers and graphene oxide in their formulation. Unlike conventional fibers, the nanotechnology-based design and wavy surface of these macrofibers significantly improve their performance within the concrete.
“Graphene oxide is one of the most promising materials for enhancing the properties of a wide range of polymers. It consists of graphene—or pure carbon—sheets stabilized with oxygen-containing groups, resulting in a versatile structure that is water-compatible, adherent to cement crystals, and easily combinable with other compounds to design materials with new or improved properties.”
Why use graphene oxide in the production of synthetic macrofibers?
Enhances the mechanical properties of polymers, thereby increasing the resistance of each fiber under loads.
Improves fiber compatibility with concrete, resulting in excellent dispersion within fresh concrete.
Generates a better fiber–cement interface, improving fiber anchorage within hardened concrete.
Evidence-Based Science
As evidence of the benefits that synthetic macrofibers with graphene oxide offer concrete, the following results are presented from a study conducted to analyze the performance of concrete reinforced with different dosages of Graphenergy® Macrofibers at 7 days.
It is important to note that the standards and limits applied were defined according to the requirements of a specific project; therefore, the reported information is for reference purposes only.
How is fiber-reinforced concrete evaluated?
The most relevant tests focus on determining how fibers improve the strength and toughness of concrete, particularly after cracking occurs.
ASTM C78 is used to determine the flexural strength of plain concrete (without fibers), measuring how much force concrete can withstand in bending before breaking.
ASTM C1609 is used to evaluate fiber-reinforced concrete, specifically its residual strength once the first crack appears, as well as its behavior under further loading or tensile forces.
Materials Used
The materials were selected in compliance with applicable standards according to the mix design and project limits, including: sand, gravel, Type II cement, water, a water-reducing admixture, and the key variable of this study: Graphenergy® synthetic macrofibers at a dosage of 35,000 to 47,000 fibers per m³ of concrete.
Results Table
Interpretation
Modulus of Rupture
Before the appearance of the first crack, concrete dosed with Graphenergy® macrofibers resisted between 36 and 41 kg/cm², meeting the specification for reasonably strong flexural concrete. It is worth noting that this test is relatively independent of fiber presence, as it depends more directly on cement paste, aggregates, and curing. As expected, the fibers did not significantly influence these results. However, the fact that the specification was met is an indication of proper fiber distribution in the mix.
Minimum Equivalent Flexural Strength Ratio 𝑅D𝑇,150
This determination highlights the true contribution of macrofibers, as it measures the residual strength of concrete after cracking. According to specifications, concrete should retain at least 21% of its original strength. Remarkably, Graphenergy® macrofibers enabled the concrete to retain between 69% and 94%, depending on fiber dosage. This demonstrates that the fibers continue to work effectively even after cracking.
Minimum Residual Strength with Net Deflection L/150 fd150
This result reflects the post-cracking behavior of concrete in terms of crack control. The results shown in the table confirm the added value of macrofibers in improving early-age resistance, offering performance more than 300% above the specification (7.7 kg/cm²).
Conclusion
The study demonstrates that concrete reinforced with Graphenergy® Macrofibers not only meets but significantly exceeds project specifications. While not all properties show a linear correlation between fiber dosage and strength—such as modulus of rupture—the results clearly show substantial improvements in post-cracking capacity and toughness. These macrofibers emerge as a novel, highly recommended alternative for concrete reinforcement in applications subjected to impacts, cyclic loads, or where ductility is essential.
The Technological Fusion Revolutionizing Materials Science
Hydrogels are polymeric networks with a hydrophilic structure that allows them to retain large amounts of water in their three-dimensional networks. From their first references in 1900 to the advancements by Wichterle and Lim in the 1960s, hydrogel technology has evolved to become a vital solution in fields such as medicine (for controlled drug or bioactive agent delivery), environmental remediation (for contaminant adsorption or soil restoration), agriculture (for water retention or soil conditioning), food industry (from texturizing agents to smart packaging), and even energy storage, among others.
“In 1900, the term ‘hydrogel’ first appeared in scientific literature to describe a colloidal gel of inorganic salts.”
Hydrogels may be chemically crosslinked through covalent bonds, physically through non-covalent interactions, or via a combination of both. They are classified into natural (including proteins such as collagen and gelatin, and polysaccharides such as starch, alginate, and agarose), synthetic (produced through chemical polymerization methods), and hybrid hydrogels. Synthetic materials have largely replaced natural ones due to better water absorption, longer lifespan, and a broader variety of raw materials.
“The water absorption capacity of hydrogels is due to hydrophilic functional groups attached to their polymer structure, while their resistance to dissolution results from crosslinks between the network chains.”
Hydrogels are mainly known and used for their excellent water absorption capabilities without altering their structure. However, their low mechanical strength and sensitivity to external stimuli such as temperature, light, or electric fields can either enhance or limit their performance in dynamic environments. Some examples include:
Temperature Sensitivity: These hydrogels expand or contract in response to heat or cold, enabling them to release contaminants, drugs, or bioactive agents—ideal for wastewater treatment or medical therapies. Their challenges include long-term stability and precise temperature responsiveness.
Photosensitivity: The integration of photoactive agents into their polymer networks can improve contaminant degradation, activate and release specific drugs, or enhance cellular growth conditions in tissue engineering. However, continuous UV exposure may lead to photodegradation of the material.
Electric Field Sensitivity: Electroactive hydrogels incorporate ionic groups that move and alter the hydrogel’s structure under an electric field, modifying its permeability to allow or block the passage of substances. This is useful for wastewater treatment and controlled water or nutrient release in agriculture. High costs and limited durability remain key challenges.
pH Sensitivity: This is achieved by incorporating ionizable functional groups (carboxyl or amino), which gain or lose protons based on environmental pH, triggering structural changes that allow water absorption or release.
How Does Nanotechnology Enhance Hydrogel Performance?
Nanotechnology—the interdisciplinary field focused on manipulating and manufacturing materials at the atomic and molecular scale (1–100 nanometers)—has made significant contributions to hydrogels, particularly in improving mechanical strength and developing smart functionalities for biomedical and environmental applications.
“To understand the nanoscale, consider that the average thickness of a human hair is approximately 60,000 nm, while a nanometer is one-millionth of a millimeter.”
What Added Value Does Graphene Bring to Hydrogels?
Graphene is a nanometric, two-dimensional (2D) carbon sheet one atom thick, with a structure similar to a benzene ring. It has attracted significant research interest due to its exceptional properties: thermal conductivity, mechanical strength, flexibility, and biocompatibility, among others, which can be transferred to hydrogel matrices.
1. Mechanical Strength:
One of the key limitations of hydrogels is their low mechanical resistance, making them unsuitable for high-stress environments. Graphene can significantly reinforce hydrogel structure, improving durability and mechanical stability.
2. Thermal Stability:
Hydrogels are sensitive to temperature changes, which can affect their performance. Graphene can enhance their thermal stability, maintaining functional properties across wider temperature ranges.
3. Antimicrobial Protection and Biocompatibility:
While hydrogels are generally biocompatible, scientific evidence shows that adding graphene improves their stability and compatibility. Its intrinsic antimicrobial properties also make hydrogels safer for infection-sensitive applications.
4. Electrical Responsiveness:
Graphene’s ability to transmit electrical signals supports cell communication in electrically active tissues (e.g., nerve, muscle, heart). It also enables controlled drug release under voltage stimulation, while minimizing overheating during electrical activation.
Although there are no graphene-based hydrogels commercially available yet, many experimental nanotechnological developments around the world are laying the groundwork for future applications, including:
Spain (2025): A study by the Spanish National Research Council and the National Hospital for Paraplegics used a reduced graphene oxide (rGO) foam scaffold to reconnect severed spinal cords in rats, promoting neuronal reconnection and vascular regeneration.
Argentina (2025): The University of Buenos Aires, CONICET, and INTI developed hydrogels resistant to hydration-dehydration cycles for nanofiltration of viruses, bacteria, fungi, and heavy metals from water.
USA (2023): A study published in Environmental Science & Technology demonstrated that graphene-based hydrogels could remove up to 95% of lead ions from aqueous solutions.
China (2022): Biomaterials Translational published a study on a hyaluronic acid–graphene oxide hydrogel combined with Senexin A for treating vascular occlusive diseases, achieving sustained release over 21 days and good biocompatibility.
USA (2022): In Applied Materials & Interfaces, researchers reported a graphene hydrogel scaffold that promoted cartilage regeneration with type II collagen expression and stable cellular growth.
Spain (2018): Researchers at the University of the Basque Country developed a starch–graphene hydrogel for flexible brain implant electrodes. The graphene was stabilized in water using sage extract, which also added antibacterial and electrical properties.
USA (2017): A porous graphene oxide hydrogel developed for water purification showed enhanced contaminant adsorption due to improved stability, nanotransport channels, and hydrogen bonding.
USA (2017): A soft, injectable hydrogel made from PEGDA–melamine and GO improved cardiac function in rats with myocardial infarction, reducing infarct size and fibrosis while promoting neovascularization.
Conclusion
Graphene-based hydrogels, and those incorporating its derivatives, offer significant structural and functional improvements. Their development represents a leap toward smarter and more adaptive systems in biomedicine, agriculture, and environmental remediation. However, like any emerging technology, widespread adoption will require overcoming regulatory and large-scale manufacturing challenges.
Written by: EF/ DHS
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In the early 18th century, scientists began to notice that some materials, when rubbed together, were mysteriously attracted to one another, while others—especially those of different natures—were consistently repelled. After many observations of the same phenomenon, researchers concluded that invisible fluids or charges were being transferred between certain objects, later described as attractive or repulsive forces.
It was Benjamin Franklin who proposed that only one type of fluid was exchanged between objects, and that differing charges resulted from an excess or deficiency of this fluid. Franklin tested this with wax and wool, observing that rubbing them caused the wool to extract the invisible fluid from the wax—leading to a surplus in the wool and a deficit in the wax. This imbalance would then generate attractive forces as the system sought to restore equilibrium.
“It was later discovered that this invisible ‘fluid’ was made up of tiny fragments of matter called electrons— the smallest known carriers of electric charge.”
Today, we understand that electric charge results from the transfer of electrons between bodies that generate electrostatic tension. However, in insulating materials like plastics, the charge remains static and localized at the point of contact. When such plastics encounter objects at different potentials—such as a person or an electronic microcircuit—static electricity may discharge via a spark or arc. This can damage electronic equipment or even trigger fires and explosions, especially in the presence of flammable substances. For this reason, the use of antistatic materials in construction products, electronics, storage centers, textiles, and many other applications is critical.
“Static charge is also known as static electricity or electrostatics.”
Plastics are found in nearly every environment. While they serve countless purposes, the static charge they accumulate can limit their use. This is why antistatic additives are often incorporated to reduce electrical resistance, making them suitable for producing antistatic packaging for electronics, automotive, or chemical industries. These materials may be biodegradable biopolymers like polylactic acid (PLA) and cellulose acetate (CA) or non-biodegradable petrochemical plastics such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Antistatic solutions are also used in construction supplies made from PVC or rubber, especially in chemical plants, gas stations, or coal mines.
How many types of antistatic additives are there?
The family of antistatic additives is broad. They include ionic, non-ionic, conductive polymers, phosphorus-based additives, and carbon-based materials. In this article, we focus on the latter—specifically, carbon black, graphite, and most notably, graphene.
“According to ASTM D257-78, the surface resistivity of antistatic materials ranges from 1.0×10⁵ to 1.0×10¹² Ω/sq.”
Graphene is a carbon nanostructure with exceptional electrical conductivity (0.96 × 10⁸ Ω·m⁻¹), making it a powerful antistatic agent. Unlike graphite—a 3D carbon structure made of millions of graphene layers—and carbon black, which is amorphous and tends to form large aggregates, graphene has a well-organized sheet-like structure with a high surface area accessible on both sides. This allows it to interact intimately with other molecules and modify the properties of many materials, particularly polymers—not only by reducing static, but also by enhancing mechanical strength, thermal resistance, and barrier properties.
Technically, graphene is composed solely of carbon atoms. But in practice, there are as many types of graphene as there are production methods—whether producing pristine graphene, graphene oxide (GO), or reduced graphene oxide (rGO)—each potentially functionalized during or after production. These functionalizations are often necessary to improve graphene’s interaction with specific polymer matrices and to impart desired properties, such as antistatic behavior.
To integrate graphene into PLA used in antistatic packaging, plasticizers like thymol, polyethylene glycol (PEG), or dibutyl sebacate (DBS) can serve as carriers—not just to reduce resistivity but also to enhance mechanical strength and barrier properties. Literature reports show that graphene in PLA can increase electrical conductivity from 1.39E-12 S/cm to 2.83E-4 S/cm. For antistatic rubber flooring, graphene can be functionalized with zinc methacrylate to reduce resistivity by up to three orders of magnitude.
Another critical factor is graphene’s proper dispersion and integration into the host matrix—something that varies depending on the material. For rubber, graphene can be functionalized with 3-glycidyloxypropyltrimethoxysilane, a coupling agent that bonds organic and inorganic materials. For PET, GO can be functionalized with p-phenylenediamine (PPD), which improves dispersion, thermal stability, and boosts antistatic performance by up to eight orders of magnitude.
In the case of cellulose acetate (CA), a biodegradable polymer gaining popularity in packaging, direct functionalization of graphene with CA molecules during synthesis improves both dispersion and static dissipation—lowering surface resistivity from 1.09×10¹² Ω/sq to 1.51×10⁹ Ω/sq. A similar strategy applies to PVC, using dioctyl phthalate (DOP), a plasticizer that can assist during graphite exfoliation to create a graphene more compatible with PVC and reduce resistivity from 10¹⁶ Ω-cm to 2.5 × 10⁶ Ω/sq.
Clearly, graphene represents a technological leap forward in the development of advanced plastics. Its capacity as an effective antistatic additive—along with its multifunctional benefits—makes it a key material for driving innovation in this field. However, its performance depends heavily on selecting the right type of graphene, the functionalization process, and its integration into the polymer matrix. As research continues, graphene is becoming an increasingly vital solution for meeting the safety, performance, and sustainability demands of the plastics industry.
Written by: EF/DHS
References
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Saif M. Jaseem and Nadia A. Ali Antistatic packaging of carbon black on plastizers biodegradable polylactic acid nanocomposites 2019 J. Phys.: Conf. Ser. 1279 012046
Zhaorui Meng, et al., Grafting macromolecular chains on the surface of graphene oxide through crosslinker for antistatic and thermally stable polyethylene terephthalate nanocomposites. 2022, RSC Advances, 12, 52, 33329.
Zijun Gao et al., Graphene nanoplatelet/cellulose acetate flm with enhanced antistatic, thermal dissipative and mechanical properties for packaging, Cellulose (2023) 30:4499
Zi-Bo Wei, et. al., Antistatic PVC-graphene Composite through Plasticizer-mediatedExfoliation of Graphite, chinese J. Polym. Sci. 2018, 36, 1361
Awareness of environmental protection and the commitment to meeting the United Nations’ 2030 Sustainable Development Goals (SDGs) have fueled the growth of the bioplastic industry. This sector is striving to take the lead in the race against synthetic products, many of which, while non-toxic and recyclable, lack biodegradability.
“Currently, only 1% of all plastic produced is bioplastic.”
What Are Bioplastics?
Bioplastics are materials derived from natural and chemical sources, obtained from renewable resources or petroleum-based derivatives. As a result, they offer major advantages, including full biodegradability, high recyclability, and a minimal carbon footprint. Additionally, bioplastics exhibit excellent optical, mechanical, antioxidant, and antimicrobial properties. However, like most materials, bioplastics also have limitations, the two most notable being low tensile strength and moisture resistance.
Despite these challenges, and given the goal of minimizing carbon footprints and reducing the use of synthetic or single-use polymers, the bioplastic industry has been evolving to overcome its limitations. This has been achieved through the incorporation of reinforcing agents such as fillers, compatibilizers, plasticizers, and even nanotechnology through the use of nanoparticles.
The most well-known bioplastics include polylactic acid (PLA), polyhydroxybutyrate (PHB), cellulose derivatives, starch, and chitosan. Among them, PLA has gained significant traction as a biodegradable thermoplastic polymer approved by the FDA. In recent years, it has emerged as a viable alternative to replace non-biodegradable fossil-based polymers traditionally used in the food, medical, agricultural, textile, and automotive industries. PLA exhibits characteristics like some petroleum-derived plastics. As a result, numerous PLA-based products are already available in the market, including blow-molded bottles, injection-molded cups, spoons, and forks, thermoformed trays and cups, paper coatings, textile fibers, and even medical supplies.
“Over 160 tons of PLA packaging are produced annually, accounting for approximately 13% of all bioplastics, making it the second most used in the sector after starch.”
PLA is produced from lactic acid through the fermentation of renewable resources such as rice, wheat, corn, sugarcane, potatoes, and beets. Due to its nature, PLA shares similar mechanical and barrier limitations with other biomaterials. As a result, various strategies have been developed to enhance its properties. For example, to improve its crystallinity and biodegradability, PLA is combined with polymers such as polyethylene glycol, ethylene vinyl alcohol, or poly(butylene adipate-co-terephthalate). To maintain its compostability, it is blended with other starch-based biopolymers such as corn, cassava, and beet starch. Finally, to improve impermeability, tensile strength, and thermal stability, graphene has emerged as a highly promising material.
“Other nanoparticles used in the bioplastic industry include silver, magnesium oxide, zinc oxide, titanium dioxide, hydroxyapatite, silica, alumina, magnetite, zirconium oxide, calcium carbonate, and recently, graphene.”
¿ What Is Graphene?
Graphene is a nanoscale structure generally extracted from graphite, a mineral composed solely of carbon. Unlike graphite, however, graphene consists of one or a few layers of tightly interconnected carbon atoms. It can be combined with numerous compounds to enhance its mechanical, thermal, electrical, barrier, and antimicrobial properties.
The benefits of graphene in biopolymers such as PLA are extensive. For example, studies have incorporated small amounts of graphene into compostable PLA films with thermoplastic cassava starch for food and agricultural applications. Remarkably, using just 0.1% graphene has resulted in:
~75% improvement in elongation resistance
~500% increase in film toughness
100% enhancement in elasticity modulus
35-50% reduction in oxygen permeability
Regarding mechanical improvements, studies conclude that in graphene-reinforced polymers subjected to tensile stress, surface fractures propagate freely unless they encounter a graphene sheet. Since graphene is a rigid material, the fracture is forced to find an alternate path, increasing deformation energy and ultimately resulting in high elongation-to-break values.
“Low concentrations of graphene are sufficient to create a crack-bridging mechanism during tensile stress. However, high concentrations can lead to nanoparticle agglomeration, causing the opposite effect.”
Increased impermeability to oxygen and moisture is another key advantage, attributed to the tortuous path created by graphene layers within the polymer. This structure hinders the penetration and movement of molecules. This phenomenon is closely linked to good graphene-polymercompatibility and dispersion, which prevents material aggregation. To improve compatibility, graphene can be chemically modified with oxygen-containing groups, leading to its most well-known variant: graphene oxide (GO). The presence of oxygen and hydrogen molecules in GO allows for further functionalization with other nanoparticles (e.g., cellulose or zinc oxide nanocrystals) or compounds (e.g., amine or amide groups), modifying its behavior based on the desired objective.
For example, a 2023 study published in Polymer Testing evaluated PLA barrier properties using GO functionalized with two types of alkylamines (decylamine (DA) and octadecylamine (ODA)) to enhance its food packaging performance. The results reported a 30%reduction in oxygen permeability with just 0.7% functionalized GO and a 50% reduction in water vapor permeability using 0.2% GO, significantly extending shelf life. If PLA can further improve its properties, it has the potential to replace polystyrene and PET—two of the most widely used materials in the packaging industry.
Graphene’s Antimicrobial Potential
Another crucial advantage of graphene—not only in PLA but in other materials—is its well-documented antimicrobial properties, which do not necessarily involve a biocidal effect. One of graphene’s mechanisms is preventing microorganism adhesion to surfaces through various pathways, regardless of their nature.
Specific research on PLA with graphene also supports this claim. Studies indicate that incorporating 1% GO in PLA films reduces film porosity, decreases oxygen permeability, and demonstrates significant antimicrobial activity against Staphylococcus aureus and Escherichia coli. These properties further enhance its potential for food packaging and preservation.
Conclusion
This article used PLA as a model to illustrate the benefits graphene can offer to the bioplastic industry. However, other biomaterials such as chitosan, cellulose, and starch can also be significantly improved with graphene.
In general, research shows that graphene has the potential to enhance multiple properties of materials. However, achieving this requires:
Selecting the right type of graphene
Determining its optimal concentration
Assessing the need for chemical modifications to optimize performance for different applications
Ultimately, striking a favorable balance between mechanical, barrier, and optical properties is essential. By leveraging graphene’s unique characteristics, the bioplastic industry can move closer to sustainable, high-performance materials with reduced environmental impact.
Written by: EF/DHS
References:
Remilson Cruz, et al., Development of biodegradable nanocomposites based on PLA and functionalized graphene oxide. Polymer Testing 124 (2023) 108066
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De Carvalho, A.P.A.; Conte Junior, C.A. Green strategies for active food packagings: A systematic review on active properties of graphene-b Trends Food Sci Technol, 103, 2020, 130
Anibal Bher et. al., Toughening of Poly(lactic acid) and Thermoplastic Cassava Starch Reactive Blends Using Graphene Nanoplatelets. Polymers 2018, 10, 95
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Ahmadi-Moghadam, et. al., Effect of functionalization of graphene nanoplatelets on the mechanical response of graphene/epoxy composites. Mater. Des. 2015, 66, 142
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Biocompatibility and Biodegradability of Graphene:
Advances and Scientific Evidence
Graphene is widely recognized for its exceptional properties and its potential to revolutionize various industries. However, as a relatively recent technology with emerging applications, concerns have arisen regarding its impact on human health and the environment. Therefore, it is essential to analyze scientific studies that have evaluated its biocompatibility and biodegradability, providing evidence of its safety and behavior in different biological systems.
Biocompatibility: Defined as the absence of allergic or immune adverse reactions to a material in the body
Over the past decade, multiple studies have demonstrated that graphene and its derivatives can be biocompatible under certain conditions. Research on its interaction with blood, cell differentiation, kidney function, neuronal activation, and bone regeneration has yielded positive results. The following key findings stand out:
2012 – Compatibility with blood and macrophage response. The nanotoxicity of graphene on macrophages was evaluated based on its effects on metabolic activity, membrane integrity, oxidative stress induction, hemolysis, platelet activation and aggregation, coagulation cascade, cytokine induction, and immune cell activation and suppression.
Results indicated that while graphene does interact with macrophages, toxicity is significantly reduced through surface functionalization. Regarding blood compatibility, both functionalized and non-functionalized graphene exhibited excellent compatibility with red blood cells, platelets, and plasma coagulation pathways, with minimal alteration in cytokine expression by human peripheral blood mononuclear cells. Additionally, no premature immune cell activation or suppression was observed up to a relatively high concentration of graphene (75 μg mL⁻¹) after 72 hours of in vitro incubation.
Conclusion: Possible graphene toxicity can be easily avoided through surface functionalization.
A. Sasidharan, et. al., Hemocompatibility and Macrophage Response of Pristine and Functionalized Graphene, Small, 2012, 8, 1251
2014-Cardiac cell differentiation. The effect of graphene on the cardiomyogenic differentiation of human embryonic stem cells (hESCs) was analyzed. Graphene was synthesized via CVD and deposited on vitronectin-coated glass, a multifunctional protein found in plasma, platelets, and the extracellular matrix, to ensure hESC viability. Cells were cultured for 21 days, and results showed that graphene promoted the expression of genes involved in gradual differentiation into mesodermal and endodermal lineage cells and subsequently into cardiomyocytes, compared to cultures on glass without graphene.
Conclusion: Graphene can provide a platform for developing stem cell therapies for heart diseases by enhancing the cardiomyogenic differentiation of human embryonic stem cells.
Tae-Jin Lee, et. al., Graphene enhances the cardiomyogenic differentiation of human embryonic stem cells, Biochem Biophys Res Commun, 2014, 452(1):174
2016-Impact on kidney function. The effect of intravenously administered graphene oxide (GO) on the kidneys of mice was studied. Results showed that GO was excreted through urine, indicating rapid transit through the glomerular filtration barrier (GFB) without nephrotoxicity. The analysis concluded an absence of kidney function impairment up to one month after GO injection at increasing doses. Histological examination found no damage to the glomerular and tubular regions of the kidneys. Ultrastructural analysis also revealed no damage or changes in podocyte slit size, endothelial cell fenestra, or glomerular basement membrane width. Endothelial and podocyte cultures restored their barrier function after >48 hours of GO exposure, with significant cellular uptake observed in both cell types after 24 hours.
Conclusion: GO is not toxic to the kidneys..
Dhifaf A. Jasim, et. al., The Effects of Extensive Glomerular Filtration of Thin Graphene Oxide Sheets on Kidney Physiology. ACS Nano 2016, 10, 12, 10753
2018-Effect on Neuronal Activation. The effect of monolayer graphene on neuronal activation was evaluated. It was identified that graphene modifies membrane-associated functions in cultured cells, meaning it adjusts the distribution of extracellular ions at the interface with neurons—a key regulator of neuronal excitability.
The observed membrane changes included stronger potassium ion currents and a shift in the fraction of neuronal activation phenotypes from adaptive to tonic activation. The study’s hypothesis suggested that graphene-ion interactions are maximized when single-layer graphene is deposited on electrically insulating substrates.
Conclusion: Graphene oxide can act as a substrate for neuronal interaction.
N. P. Pampaloni, et. al., Single-layer graphene modulates neuronal communication and augments membrane ion currents, Nat. Nanotechnol., 2018, 13, 755
2018-Adjuvant in the Proliferation of Pulmonary and Neuronal Cells. Graphene oxide “papers” of different sizes and thicknesses were fabricated as a substrate for the culture of human pulmonary and neuronal cells. Their capacity for cell adhesion and proliferation was evaluated, along with a possible cytotoxic response by detecting lactate dehydrogenase (LDH) in cell supernatants.
Conclusion: Graphene oxide can act as a biocompatible cellular substrate for cell growth without cytotoxic effects, opening greater possibilities for tissue engineering, regenerative medicine, and bionic applications.D. A. Jasim, et. al., Graphene-based papers as substrates for cell growth: Characterisation and impact on mammalian cells, FlatChem, 2018, 12, 17
2020- Biocompatibility of Graphene in Dental Materials. The biocompatibility of a graphene-containing restorative material and dental cement was studied on a mandibular defect in an animal model. Cytotoxicity was evaluated in vitro at 24 hours on human dental follicle stem cells and oral keratinocytes. In vivo studies were conducted seven weeks after implantation, including histological analysis of collected bone tissue, plasma biochemistry, oxidative stress assessment, and subchronic organ toxicity analysis.
The in vitro results showed that the materials did not induce toxicity in cells. In vivo, the animal models exhibited no symptoms of acute toxicity or local inflammation. No changes were detected in organ weights, and histological analysis revealed no alterations in liver or kidney tissues. Systemic toxicity of the materials in organs was not observed.
Conclusion: The study provides further evidence of the potential of graphene-based dental materials for bone regeneration and biocompatibility.
A. Dreanca, et. al., Systemic and Local Biocompatibility Assessment of Graphene Composite Dental Materials in Experimental Mandibular Bone Defect. Materials 2020, 13, 2511; doi:10.3390/ma13112511
2022- Risks of Graphene in Microplastics. The study was conducted on a composite of polyamide 6 or Nylon-6, a plastic commonly used in the automotive and sports industries, reinforced with reduced graphene oxide (rGO 2.5%). The material was then subjected to wear to emulate natural processes throughout its useful life, releasing particles approximately between 1.9 µm and 3.2 µm in size. To analyze the effects of the worn particles along the most likely exposure routes, in vitro human cell models of the lungs, gastrointestinal tract, skin, and immune system were used, as well as an animal model to study pulmonary exposure in vivo.
At the end of the study, only limited acute responses were found after exposure to the microplastics in the different models. Only the free rGO induced significant adverse effects, particularly in macrophages.
Conclusion: Microplastics with graphene suggest a low risk to human health. Graphene materials should not be inhaled.
S. Chortarea, et. al., Hazard assessment of abraded thermoplastic composites reinforced with reduced graphene oxide, Journal of Hazardous Materials 435 (2022) 129053.
2023- Pulmonary Function. The biological response, distribution, and biopersistence of four types of graphene in the lungs of mice were analyzed up to 28 days after a single oropharyngeal aspiration. The results showed that none of the materials induced a strong pulmonary immune response, with neutrophils being more effective at internalizing, degrading, and eliminating small graphene sheets (~50nm) than macrophages, as larger sheets (~8µm) may have greater persistence.
Conclusion: Graphene does not cause an inflammatory response in the lungs; however, it is important to consider the size of the sheets, as smaller ones are easier to eliminate from the airways and, therefore, safer.
Thomas Loret, et. al., Lung Persistence, Biodegradation, and Elimination of Graphene-Based Materials are Predominantly Size-Dependent and Mediated by Alveolar Phagocytes, Small, 2023,19(39): e2301201
2024- Pulmonary and Cardiovascular Function. An in vivo study was conducted to evaluate the effect of graphene oxide inhalation on pulmonary and cardiovascular function in healthy humans. For the trial, 14 volunteers inhaled small and ultrafine graphene oxide sheets at a controlled concentration during two-hour repeated visits. Heart rate, blood pressure, pulmonary function, and inflammatory markers were unaffected regardless of particle size; blood analysis showed few differential plasma proteins, and thrombus formation increased slightly in an ex vivo arterial injury model.
Conclusion: Graphene oxide inhalation can be tolerated and is not associated with apparent harmful effects in healthy humans. The study lays the groundwork for further human studies that examine a larger number of individuals as well as different types and doses of graphene.
Jack P. M. Andrews, First-in-human controlled inhalation of thin graphene oxide nanosheets to study acute cardiorespiratory responses. Nature nanotechonoly, 2024, 19, 705.
Biodegradation: Process by which a substance is broken down by living organisms through enzymatic or metabolic mechanisms
One of the most relevant aspects in evaluating the safety of graphene is its biodegradability. Research conducted under the Graphene Flagship project has demonstrated that graphene and graphene oxide can be successfully degraded, as follows:
2018 – Researchers affiliated with the European Union’s Graphene Flagship project, from institutions such as the National Center for Scientific Research (CNRS) in France, the University of Strasbourg, the Karolinska Institute, and the University of Castilla-La Mancha (UCLM), through studies such as “Dispersibility-Dependent Biodegradation of Graphene Oxide by Myeloperoxidase” (2015), “Graphene Oxide is Degraded by Neutrophils and the Degradation Products Are Non-Genotoxic” (2018), and “Peroxidase Mimicking DNAzymes Degrade Graphene Oxide” (2018), discovered that the enzyme myeloperoxidase (MPO) successfully degrades both graphene and graphene oxide.
Myeloperoxidase (MPO): An enzyme released by neutrophils, cells responsible for eliminating any foreign body or bacteria entering the body, present in the lungs. When a foreign body or bacteria is detected, neutrophils surround it and secrete MPO to destroy the threat.
Professor Andrea C. Ferrari, Head of Science and Technology at Graphene Flagship and Chairman of its Management Panel, stated: “The report on a successful pathway for graphene biodegradation is a very important step in ensuring the safe use of this material in applications. The Graphene Flagship has placed research into the health and environmental effects of graphene at the center of its program from the beginning. These results strengthen our confidence in the potential of graphene for biomedical and technological innovations.”
Cristina Martın, et al., Biocompatibility and biodegradability of 2D materials: graphene and beyond, Chem. Commun., 2019, 55, 5540
This discovery is crucial, as it confirms that graphene is not an accumulative material in the human body or the environment. Instead, it can be naturally processed and eliminated, reducing the risks of long-term toxicity.
Conclusion
Graphene and its derivatives have demonstrated a high degree of biocompatibility and controlled degradability in various scientific studies. While challenges remain, current evidence supports its safety in biomedical, industrial, and environmental applications.
The key to its proper use lies in selecting the right type of graphene and its functionalization, which helps minimize risks and enhance its benefits. Thanks to advances in research, the viability of graphene as an innovative, safe, and sustainable material is becoming increasingly clear, with applications ranging from regenerative medicine to advanced nanotechnology.
The continuous development of scientific studies will further strengthen its position as one of the key technologies of the future, ensuring its responsible and effective implementation across different industries.
Transforming Properties for Innovative Applications
Graphene is a carbon nanostructure in sheet form with multifunctional properties. Although it is usually chemically inert, under certain conditions and due to its extensive surface area, it can interact with other molecules or particles to generate a wide variety of derivatives with specific characteristics, as will be discussed below.
Chemically inert: incapable of reacting or inactive.
The interactions graphene can undergo are also known as functionalizations or dopings. These are chemical modifications aimed at giving graphene new properties or “functions.” For example, to make it hydrophilic, since it is well-known that graphene is inherently hydrophobic, making it challenging to manipulate. This quality leads to the most common functionalization, which involves anchoring oxygenated groups such as hydroxyl, epoxy, carbonyl, and carboxyl along its carbon structure, resulting in its most well-known variant: Graphene Oxide (GO).
“Graphene functionalization changes surface chemistry, such as charge and hydrophobicity.”
Covalent and Non-Covalent Functionalization
Graphene can be functionalized through covalent or non-covalent means. The former refers to the formation of strong chemical bonds with other particles or molecules that alter the structure and hybridization of its carbon atoms. This type of functionalization allows better control over the process compared to non-covalent functionalization (Van der Waals forces, electrostatic interactions, hydrogen bonding, or π-π stacking), which does not alter its chemical structure since the particles or molecules are adsorbed on its surface in a weaker and reversible manner.
“Graphene’s chemical functionalization is a vital tool for its integration into the world of applications.”
As mentioned earlier, the most well-known graphene functionalization is graphene oxide, also found in the literature as graphite oxide or oxidized graphene. This variant is defined as a single graphitic monolayer covalently functionalized with hydroxyl and epoxy groups above and below each graphene sheet, as well as carbonyl and carboxyl groups typically on its edges.
These modifications to the graphene structure have distinct advantages. For one, they improve its dispersion in aqueous media, prevent re-agglomeration, provide more interaction sites for additional functionalizations, facilitate incorporation into three-dimensional materials (e.g., polymers), and ultimately allow for greater production scalability of both GO and graphene itself. This is because the oxygenated groups anchored to the GO surface can be removed through chemical, electrochemical, or thermal methods that partially restore the graphene structure, making GO a precursor material.
This is significant because one reason there are few graphene applications in the market is that common production methods yield low or insufficient amounts for industrial use. Below are some examples of unrelated functionalizations of graphene and its derivatives for various applications.
Graphene Functionalization with Polymers
For proper graphene functionalization, it is essential to form strong bonds between graphene’s carbon atoms and polymers through covalent functionalizations. However, this is a complex task since graphene consists only of carbon and lacks functional groups for conjugation. For this reason, GO and reduced graphene oxide (rGO) are the primary precursors for graphene functionalization with polymers via non-covalent bonds.
One example is the direct functionalization of GO through π-π stacking during polymer extrusion processes, where high temperatures and strong shear forces fracture aggregates and allow polymer chains to diffuse into the GO sheets’ spaces, facilitating proper integration. In this way, GO can transfer its properties—primarily mechanical—to the polymer.
However, GO can also be functionalized with other structures, such as chitosan, to integrate into polymers like polyvinyl propylene (PVP) and polyvinyl alcohol (PVA) or directly functionalized with polymethyl methacrylate (PMMA) or polyethylene glycol (PEG) for bioapplications.
Another example of GO functionalization is with polyaniline, a conductive polymer, to create electrode materials with improved electrochemical performance and greater long-term stability. Similarly, functionalization with polypyrrole-based compounds enhances energy storage capacities. GO can also be functionalized with metallic nanoparticles like copper or silver to increase electrical conductivity in conductive coatings or inks.
Graphene Functionalization for Biomedical Applications
Dispersion stability of graphene is an essential requirement for success in all applications. For this reason, GO is the most commonly used variant. Additional functionalizations can be made through the oxygenated groups present across its surface, which not only improve graphene’s dispersion in water but also increase its biocompatibility and safety. Furthermore, its extensive surface area, including graphene’s intrinsic hydrophobic regions, allows the adsorption of organic molecules, DNA, RNA, proteins, ions, or polymers via non-covalent interactions (π-π stacking, hydrogen bonding, and electrostatic interactions) for various medical applications. Examples include designing biocatalytic platforms through functionalization with gold nanoparticles for use in diagnostic biosensors, with fluorescent pigments for imaging, with silver nanoparticles for antimicrobial purposes, or with polymers like polyethylene glycol for drug anchoring and delivery.
Graphene Functionalization for Photovoltaic Device Fabrication
Graphene’s properties that have positioned it as a strong candidate for optimizing photovoltaic devices include its lightness, transparency, large surface area, and lack of a bandgap due to its high mobility and electrical conductivity at room temperature.
Bandgap: energy barrier that electrons must overcome to flow as electrical current.
Over the years, graphene’s performance has been studied in interfacial layers, active layers, and as transparent conductive electrodes. Incorporating graphene into silicon solar cells can increase energy conversion efficiency by 20%; in perovskite graphene solar cells, higher current density and efficiency exceeding 80% have been observed. For dye-sensitized solar cells utilizing graphene oxide functionalized with titanium dioxide (TiO2), a plasmonic effect has been observed, demonstrating better light capture and charge transport efficiency.
Other examples of functionalizations tested on graphene include poly(3-hexylthiophene) (P3HT), gold nanoparticles, poly(3,4-ethylenedioxythiophene): poly(styrenesulfonic acid), bis(trifluoromethanesulfonyl)amide, and metals like copper.
Graphene Functionalization for Lubricant Fabrication
In traditional synthetic oils, certain additives with nanoparticles are used to reduce energy loss and wear. This is justified by their ability to create protective films between the contact interfaces of rough surfaces, reducing friction and wear. However, a limitation for their use in lubricating oils, especially those with low viscosity, is the nanoparticles’ limited stability.
Graphene’s tribological or lubricating efficiency originates from its high mechanical strength, flat and thin structure with weak interlayer bonds, high thermal stability, and extensive surface area. Nevertheless, as in many other applications, graphene doping with nitrogen, phosphorus, sulfur, boron, and fluorine, or with alkyl groups like octadecylamine, octadecyltrichlorosilane, and octadecyltriethoxysilane, or modifications with amines such as alkylamines further improve its tribological properties. Additionally, polymer functionalization has shown good results not only for tribology but also for dispersion and stability, e.g., with polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), poly(ether-ether-ketone), and polyethyleneimine. Other studies have also reported functionalizations of graphene with octadecylamine for purposes such as lubricant biodegradability, among others.
The above describes only a few examples of the countless functionalizations that can be applied to graphene for specific applications. In many cases, the presence of graphene within a material or mixture is insufficient to generate a notable effect. Fortunately, its field of action is so broad that, when properly synthesized and utilized, it is possible to achieve astonishing results.
Written by: EF/DHS
Surface Functionalization of Graphene-Based Materials: Biological Behavior, Toxicology, and Safe-By-Design Aspects , Adv. Biology 2021, 5, 2100637
Applications of Pristine and Functionalized Carbon Nanotubes, Graphene, and Graphene Nanoribbons in Biomedicine. Nanomaterials 2021, 11, 3020
Graphene and its derivatives for solar cells application, Nano Energy Volume 47, May 2018, Pages 51-65
Effect of HNO3 functionalization on large scale graphene for enhanced tri-iodide reduction in dye-sensitized solar cells, journal of materials chemistry, 2012, 38
The development of TiO2-graphene oxide nano composite thin films for solar cells, Results in Physics 11 (2018) 46
Graphene/Si Schottky solar cells: a review of recent advances and prospects, RSC Adv., 2019, 9, 863–877 |
Tribological improvement of potential lubricants for electric vehicles using double functionalized graphene oxide as additives, Tribology International 193 (2024) 109402
Graphene-Based Nanomaterials as Lubricant Additives: A Review, Lubricants 2022, 10, 273
A Revolution in Decontamination and Industrial Efficiency
Aerogels are synthetic, translucent materials with a gel-like appearance in which the liquid content is replaced with air or gas, creating a porous network of interconnected nanostructures. They are typically made from silica, alumina, chromium oxide, titanium, tin, or carbon, each offering specialized properties for different industries. For instance, in construction, they provide thermal and acoustic insulation; in food, they control moisture; in medicine, they release drugs and repair bone defects; in agriculture, they optimize water usage; and in environmental purification, they adsorb contaminants in water and air.
“Despite their advantages, aerogels face challenges such as fragility and high costs, prompting ongoing research to improve them.”
Graphene, a planar nanostructure consisting of one to ten layers of tightly bonded carbon atoms, boasts extraordinary mechanical, thermal, and electrical properties transferable to other materials. However, to ensure this transfer, graphene often undergoes additional functionalization with oxygen groups or chemical/physical dopants like DNA molecules, metallic ions, nanoparticles, or polymers. These modifications inhibit the π-π stacking of graphene layers, improving their interaction and stability—key challenges given graphene’s tendency to aggregate.
“A critical factor for graphene’s performance is the proper dispersion and distribution of its layers throughout the host material matrix.”
The intersection of aerogels and graphene lies in the fact that aerogels provide a three-dimensional macroscopic structure where graphene can remain stable without aggregating. Additionally, graphene enhances aerogel properties, such as lightweight construction, electrical conductivity, thermal insulation, compressibility, and elasticity. It also allows functionalization with other materials like cobalt hydroxide, cobalt oxide, manganese dioxide, molybdenum oxide, molybdenum disulfide, nitrogen, sulfur, or boron to improve electrochemical detection performance, supercapacitor efficiency, electrocatalytic functions, or contaminant adsorption.
Graphene Aerogels for Decontamination:
Graphene’s adsorbent capabilities are well-documented, particularly in its oxidized form, graphene oxide (GO), which offers a large surface area and numerous interaction sites for capturing pollutants. However, challenges such as the difficulty of removing adsorbed substances and recycling GO sheets limit practical applications. Recent advancements suggest that three-dimensional graphene aerogels effectively prevent GO aggregation during adsorption and enhance regeneration capabilities. These new structures, with their extremely low density, high porosity, and large surface area, facilitate contaminant diffusion and adsorption within the 3D network while enabling recyclability.
A 2024 study published in the renowned journal Nature detailed two methods for producing graphene aerogels. This research evaluated the photocatalytic capacity of both materials, finding superior performance compared to non-graphene counterparts. The study also analyzed various toxic organic solvents, pigments, and oils, such as formaldehyde, dichloromethane, acetone, ethanol, methanol, pump oil, castor oil, and silicone oil, achieving higher decontamination rates. Additionally, graphene aerogels have been shown to remove up to 99% of heavy metals from water, outperforming conventional adsorbents like activated carbon and other treatment methods like ion exchange, coagulation, and filtration. These advantages stem from their larger surface area, higher adsorption capacity, longer lifespan, and regenerative properties.
In air decontamination, most systems use high-efficiency particulate air (HEPA) filters with activated carbon. However, their limited adsorption capacity necessitates frequent maintenance and filter replacements. Addressing this issue, a study by Tianjin University in China explored the photocatalytic capability of titanium dioxide combined with the adsorption capacity of graphene aerogels. The research concluded that the synergy between these materials offers significant advantages over conventional filtration systems.
This demonstrates how two distinct technologies can merge to create synergies and address various challenges. For Energeia-Graphenemex, a leading Latin American company in graphene material production and application development, it is inspiring to see how graphene technology is gradually making a positive impact across different industrial sectors.
Authored by: EF/DHS
References:
Gaelle Nassar, et. al., A review on the current research on graphene-based aerogels and their applications. Carbon Trends 4 (2021) 100065;
Ting Yao et. al., Preparation of β-cyclodextrin-reduced graphene oxide aerogel and its application for adsorption of herbicides. Journal of Cleaner Production, 468, (2024) 143109;
Karabo G. Sekwele et. al., Cellulose, graphene and graphene‑cellulose composite aerogels and their application in water treatment: a review. Discover Materials (2024) 4:23;
Ashish K. Kasar et al., Graphene aerogel and its composites: synthesis, properties and applications. Journal of Porous Materials (2022) 29:1011
In previous articles, we discussed the cement industry’s impact on CO₂ emissions and the commitments made to reduce them by 2050. Today, we explore how carbonation—a process generally seen as a concrete pathology—could help offset some CO₂ emissions from cement production.
What is Carbonation?
In concrete, carbonation is a natural process where CO₂ from the environment reacts with moisture in the concrete, converting the alkaline calcium hydroxide in cement paste to calcium carbonate with a more neutral pH. This reaction lowers the concrete’s pH from around 12–13 to approximately 9, exposing steel reinforcements to corrosion.
What Affects Carbonation?
Carbonation rate depends on the diffusion of CO₂ and its reactivity with the cement matrix, which is in turn influenced by the matrix’s microstructure, hydration products (calcium hydroxide, calcium silicate hydrate, alkaline oxides, etc.), and pore structure (distribution, size, and saturation). Therefore, carbonation proceeds more slowly in low-permeability or dry concretes than in permeable ones with 50–60% humidity. To reduce porosity and calcium hydroxide levels, micrometric additives like fly ash, blast furnace slag, metakaolin, silica fume, and some nanomaterials are used during concrete production, alongside practices like applying surface coatings.
Carbonation as an Emission Reduction Tool
Carbonation can be viewed in two ways: first, as a concrete pathology, and second, as a CO₂-reducing opportunity. There are two types of carbonation: natural and accelerated. Natural carbonation is slow and does not capture CO₂, while accelerated (or mineral) carbonation uses high CO₂ concentrations, speeding up cement hydration and producing carbonates in which CO₂ is permanently stored in a thermodynamically stable mineral form. This process, known as recarbonation, involves the same carbonate used as a raw material in cement production. Companies like Blue Planet, Carbon Cure, Solidia Technologies, and Carbi Crete are developing strategies to sequester up to 17 kg of CO₂ per cubic meter of prefabricated concrete, as this process requires controlled conditions.
Graphene Oxide (GO) and Its Impact
Graphene oxide (GO) is a carbon nanostructure whose multifunctionality offers numerous benefits across industries. In concrete, GO enhances mechanical strength and durability, though its effects on carbonation and CO₂ capture are less well-documented.
Research conducted by the University of Arlington, Texas, in 2022 examined GO’s interaction mechanism in concrete cured under accelerated carbonation. Results indicated that GO, by improving cement hydration, refines concrete pores with calcium carbonate precipitated on hydration products and cement particles, limiting chemical reactions between hydration products and CO₂ under continuous CO₂ flow. The study concluded that GO not only enhances concrete’s mechanical properties but also helps capture and store up to 30% of atmospheric CO₂ during early curing stages.
Authored by: EF/ DHS
References
Geetika Mishra, et al., Carbon sequestration in graphene oxide modified cementitious system, Journal of Building Engineering, 2022, 62, 105356;
Nur Azni Farhana Mazri et al., Graphene and its tailoring as emerging 2D nanomaterials in efficient CO2 absorption: A state-of-the-art interpretative review. Alexandria Engineering Journal, 2023, 77, 479;
Mohd Hanifa et al., A review on CO2 capture and sequestration in the construction industry: Emerging approaches and commercialised technologies, Journal of CO2 Utilization, 2023, 67, 102292;
Yating Ye et al., Optimizing the Properties of Hybrids Based on Graphene Oxide forCarbon Dioxide Capture, Ind. Eng. Chem. Res. 2022, 61, 1332;
Sanglakpam Chiranjiakumari Devi et al., Influence of graphene oxide on sulfate attack and carbonation of concrete containing recycled concrete aggregate, Construction and Building Materials, 2020, 250, 118883
The Promise of Graphene Oxide in Intumescent Coatings
Intumescent coatings are specialized paints applied to concrete and steel structures in industrial and residential buildings to offer fire protection. They provide safety by allowing enough time for evacuation and assistance in the event of a fire.
During a fire, these coatings expand and form a carbonized foam that isolates the fire and limits its spread, while simultaneously releasing non-combustible gases that reduce the oxygen concentration around the structures, protecting them from significant damage for approximately 1 to 3 hours.
The main components of intumescent coatings are a polymeric binder, an acid source (e.g., ammonium polyphosphate – APP), an expansion additive (e.g., melamine – MEL), a carbon source (e.g., pentaerythritol – PER), and other filler elements (e.g., expandable graphite), which often influence the expansion factor and fire retardancy.
Despite their efficiency, the carbonized foam formed by the APP-MEL-PER system may have poor oxidation resistance at high temperatures, leading to lower fire-retardant efficiency and easier destruction during combustion. Therefore, other additives such as calcium carbonate, aluminum hydroxide, silica, and certain carbon materials have been explored to enhance their protection. For example, expandable graphite in epoxy coatings improves thermal degradation and fire resistance; carbon nanotubes reduce the heat release rate in polymers, and graphene oxide (GO), thanks to its reticular nanostructure, has been identified as an effective thermal barrier to prevent flame diffusion and reduce heat propagation. This occurs because GO, when evenly dispersed within the coating matrix, forms a “tortuous path” that reduces the thermal diffusion rate and matrix decomposition, thus improving fire resistance and mechanical strength.
Although no intumescent coatings with graphene oxide are currently on the market, research has shown that GO can improve the APP-MEL-PER system by promoting the decomposition reaction of APP, which accelerates the formation of phosphoric acid that reacts with PER to form carbon. While it has been observed that GO may slightly decrease the thermal stability of coatings, its presence encourages gas production and intumescent coefficients, reducing thermal conductivity.
Energeia-Graphenemex®, in collaboration with a renowned Mexican specialized coatings company, is working on a new development to launch the first intumescent coating with graphene oxide to continue placing Mexico at the forefront of new technologies.
Authored by: EF/DHS
References:
Wang Zhan et al., Influence of graphene on fire protection of intumescent fire retardant
coating for steel structure, Energy Reports 6 (2020) 693;
Qiuchen Zhang et al., Effects and Mechanisms of Ultralow Concentrations of Different Types of Graphene Oxide Flakes on Fire Resistance of Water-Based Intumescent Coatings, Coatings 2024, 14, 162;
M. Sabet, et al., The Effect of Graphene Oxide on Flame Retardancy of Polypropylene and Polystyrene, Materials Performance and Characterization 9, no. 1 (2020): 284;
Cheng‑Fei Cao et al., Fire Intumescent, High‑Temperature Resistant, Mechanically Flexible Graphene Oxide Network for Exceptional Fire Shielding and Ultra‑Fast Fire Warning, Nano-Micro Lett. (2022) 14:92;
Quanyi Liu et al., Recent advances in the flame retardancy role of graphene and its derivatives in epoxy resin materials. Composites Part A: Applied Science and Manufacturing, 2021, 149, 106539
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