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Carbon fiber has become increasingly popular in various industries due to its exceptional strength, lightweight nature, and corrosion resistance. It is commonly used in aerospace, automotives, and sporting goods applications. However, one question that arises does carbon fiber conduct electricity?. In this article, let Europlas’s explore the electrical conductivity of carbon fiber and its significance in different contexts.

1. What are Carbon Fibers?

Carbon fibers, also known as carbon fibers (abbreviated as CF), graphite fiber, or graphite fiber, are thin strands with a diameter ranging from 5 to 10 micrometers (0.00020–0.00039 in) primarily composed of carbon atoms. 

Carbon fiber consists of carbon atoms that are bonded together, forming an extended chain structure. It possesses numerous advantages, including exceptional stiffness, high tensile strength, an impressive strength-to-weight ratio, remarkable chemical resistance, resistance to high temperatures, and minimal thermal expansion. However, the question: “does carbon fiber conduct electricity?” is currently a topic of great interest among many people.

Carbon fiber materials are available in various forms, including yarns, uni-directional fibers, weaves, braids, and other configurations, which are utilized to create composite components. The properties of carbon fiber parts closely resemble those of steel, while their weight is comparable to that of plastic. 

What are Carbon Fibers?

What Does Carbon Fiber Look Like?

Carbon fiber has a distinct appearance characterized by black strands or yarns known as "Tows." It is available in various formats, including spools of tow, unidirectional configurations, weaves, braids, and more, all of which are utilized in the fabrication of carbon fiber composite parts.

Each of these formats can be further categorized into sub-categories, which involve additional refinement. For instance, different carbon fiber weaves can yield diverse properties in the resulting composite part.

What Does Carbon Fiber Look Like?

Classification and Types

Carbon fibers can be categorized into different groups based on their modulus, strength, precursor fiber materials, and final heat treatment temperature:

Modulus-Based Classification:

• Ultra-high modulus (UHM) fibers: Modulus > 450 GPa
• High modulus (HM) fibers: Modulus between 350-450 GPa
• Intermediate modulus (IM) fibers: Modulus between 200-350 GPa
• Low modulus and high-tensile (HT) fibers: Modulus < 100 GPa, tensile strength > 3.0 GPa
• Super high-tensile (SHT) fibers: Tensile strength > 4.5 GPa

Carbon fibers are classified based on their modulus and tensile strength, allowing for a better understanding of their performance characteristics and applications. Each type of carbon fiber has its own unique properties, making it suitable for specific applications in industries where lightweight, high-strength materials are required. 

As technology advances, we can expect further innovations and advancements in the field of carbon fiber, expanding its range of applications and contributing to a more sustainable and efficient future.

Precursor Fiber Materials:

• PAN-based carbon fibers are the most widely used and commercially available type of carbon fibers. PAN stands for polyacrylonitrile, a synthetic polymer used as the precursor material.
• Pitch-based carbon fibers are produced using petroleum or coal pitch as the precursor material. The carbonization process involves heating the pitch fibers to high temperatures. 
• Mesophase pitch-based carbon fibers are a specialized type of carbon fibers derived from mesophase pitch. Mesophase pitch is a liquid crystalline material that forms during the heat treatment of certain organic precursors.
• Isotropic pitch-based carbon fibers are produced from isotropic pitch, which is derived from coal tar or petroleum feedstock. These fibers have isotropic properties, meaning they exhibit similar mechanical characteristics in all directions.
• Rayon-based carbon fibers are manufactured from regenerated cellulose or viscose rayon fibers. Rayon fibers are chemically treated and then carbonized to produce carbon fibers. 
• Gas-phase-grown carbon fibers, also known as vapor-grown carbon fibers, are produced using chemical vapor deposition (CVD) techniques. In this process, carbon-rich gases, such as hydrocarbons, are decomposed at high temperatures, and carbon fibers are grown on a substrate. 

Carbon fibers can be classified based on the precursor fiber materials used in their production. The types include PAN-based, pitch-based, mesophase pitch-based, isotropic pitch-based, rayon-based, and gas-phase-grown carbon fibers.

Each type of carbon fiber possesses unique properties that make them suitable for specific applications across various industries. The continued research and development in carbon fiber technology are expected to bring further advancements and widen the range of applications for this remarkable material.

Heat Treatment Temperature-Based Classification:

• Type-I, high-heat-treatment (HTT) carbon fibers: Final heat treatment temperature above 2000°C, often associated with high-modulus fibers.
• Type-II, intermediate-heat-treatment (IHT) carbon fibers: Final heat treatment temperature around or above 1500°C, often associated with high-strength fibers.
• Type-III, low-heat-treatment carbon fibers: Final heat treatment temperature not exceeding 1000°C. These fibers have low modulus and low strength characteristics.

The modulus of carbon fiber refers to its stiffness or resistance to deformation. Carbon fibers are classified into different categories based on their modulus values. These classifications provide insights into the specific applications and performance characteristics of each type. Each type of carbon fiber has its own unique properties, making it suitable for specific applications in industries where lightweight, high-strength materials are required.

Classification and types Carbon Fiber

2. How Is Carbon Fiber Made?

Before investigating: “Does carbon fiber conduct electricity?”, it is important to understand: “How Is Carbon Fiber made?”. Here is comprehensive information about the materials and the process of manufacturing carbon fibers.

Raw Materials

The material utilized in the production of carbon fiber is known as the precursor. Approximately 90% of carbon fibers are made from polyacrylonitrile (PAN), while the remaining 10% are derived from rayon or petroleum pitch. These substances are organic polymers characterized by extensive chains of molecules linked together by carbon atoms. The specific composition of each precursor varies among different companies and is generally regarded as a confidential trade secret.

Throughout the manufacturing process, a variety of gases and liquids are employed. Some of these materials are intended to react with the fiber in order to achieve specific effects, while others are designed to be non-reactive or prevent certain reactions with the fiber. Similar to the precursors, the precise compositions of many process materials are proprietary.

The production of carbon fibers involves a combination of chemical and mechanical processes. The precursor is transformed into elongated strands or fibers, which are then subjected to high temperatures without exposure to oxygen. The absence of oxygen prevents the fiber from burning. Instead, the elevated temperature causes the atoms within the fiber to undergo intense vibrations, resulting in the expulsion of most non-carbon atoms. This process, known as carbonization, yields a fiber composed of long, tightly interconnected chains of carbon atoms, with only a small number of non-carbon atoms remaining.

How Is Carbon Fiber Made?

Manufacturing Process

After attaining the appropriate blend of process materials, the precursor is drawn into extended strands or fibers and subsequently subjected to high temperatures within an oxygen-free environment (known as pyrolysis) to undergo carbonization. During carbonization, the majority of non-carbon atoms are expelled, resulting in the formation of intricately intertwined carbon chains, with only a minor fraction of non-carbon substances remaining. Generally, this process comprises five distinct steps:

1. Spinning

The first process involved in carbon fiber production is referred to as the spinning process. It begins with the mixture of Acrylonitrile plastic powder and another plastic, such as methyl acrylate or methyl methacrylate, which is then subjected to a conventional suspension or solution polymerization process with a catalyst. This process leads to the formation of a polyacrylonitrile plastic.

Subsequently, the plastic is spun into fibers using various techniques. In one particular method, specific chemicals are injected through small nozzles into a chemical bath, causing the plastic to coagulate and solidify into fibers. The spinning step plays a crucial role in determining the internal atomic structure of the fibers. Following this, the fibers undergo washing and stretching processes to achieve the desired fiber diameter.

2. Stabilizing

Prior to carbonization, carbon fibers undergo a chemical modification known as stabilization, which enhances their thermal stability by transforming their linear atomic bonds into ladder bonds. The fibers are subjected to heating in an oxygen-rich environment at temperatures ranging from 200 to 300°C for a duration of 30 minutes to two hours.

This heating procedure prompts the carbon atoms to interact with oxygen atoms from the air, leading to a rearrangement of the molecular structure into a more thermally stable bonding configuration. It is essential to carefully regulate this exothermic process to prevent overheating of the fibers. Various techniques are employed in the stabilization of carbon fibers.

3. Carbonizing

Carbonization follows the stabilization process, where the thermally stable fibers are subjected to high temperatures of 1,000-3,000°C for a few minutes in an oxygen-free environment. The absence of oxygen prevents the fibers from burning under such extreme heat conditions. It is crucial to maintain a higher gas pressure inside the furnace compared to the atmospheric pressure outside and ensure the sealing of fiber entry and exit points to prevent the entry of oxygen into the furnace.

At these elevated temperatures, the fibers undergo the expulsion of non-carbon atoms, resulting in the formation of tightly bonded carbon crystals. These carbon crystals align themselves parallel to the long axis of the carbon fiber.

4. Surface Treatment

The carbonization process results in smooth fibers that do not adhere well to epoxies and other materials utilized in composite product manufacturing. Therefore, the surface undergoes a slight oxidation treatment. This oxidation process enhances the chemical bonding properties of the surface and also etches it, facilitating improved adhesion of chemicals.

To achieve oxidation, the fibers are sometimes immersed in gases like carbon dioxide, air, or ozone, or in liquids such as nitric acid or sodium hypochlorite. In other cases, electrolysis is employed by immersing the positively charged fibers in a bath containing electrically conductive substances.

Regardless of the method chosen for surface treatment, it is crucial to conduct the process under meticulous and expert supervision to prevent the introduction of surface defects that could potentially result in material failure in the future.

5. Sizing

After the completion of oxidation, a protective coating is applied to the fibers to prevent damage during winding onto bobbins or weaving into fabrics. This coating process is referred to as sizing, and the selection of sizing materials is done meticulously to ensure compatibility with the adhesives used in composite structure formation. Common coating materials for sizing include polyester, nylon, urethane, and epoxy.

After the sizing process, the carbon fibers are wound onto bobbins and placed into spinning machines to be twisted into yarns of different sizes. These yarns can be further utilized for weaving fabrics or incorporated into composite materials.

How Is Carbon Fiber Made?

3. Does Carbon Fiber Conduct Electricity?

Before addressing the conductivity of carbon fiber, it is essential to understand what conductivity means. Electrical conductivity refers to the ability of a material to conduct an electric current. Materials can be broadly classified as conductors, semiconductors, or insulators based on their conductivity properties.

Does carbon fiber conduct electricity? Carbon fiber itself is not inherently conductive. Unlike metals such as copper or aluminum that readily allow the flow of electric current, pure carbon fiber is considered an insulator. This lack of conductivity can be attributed to the molecular structure of carbon fiber, which consists of tightly bound carbon atoms arranged in a crystalline lattice.

Factors Affecting Conductivity:

Carbon fiber can undergo a process called graphitization, where the carbon atoms are rearranged into a more ordered structure. This results in an increase in electrical conductivity. However, the graphitization process may also affect the mechanical properties of the fiber.

Carbon fiber is often used in composite materials, where it is combined with other substances like epoxy resin. The electrical conductivity of the composite material will depend on the conductivity of both the carbon fiber and the matrix material. In some cases, the addition of conductive additives or fillers can enhance the overall conductivity of the composite.

So, does carbon fiber conduct electricity? Yes, carbon fibers do conduct electricity. The electrical conductivity of carbon fiber is typically improved by incorporating reinforcing materials. Additionally, they can also generate electricity when subjected to magnetic fields.

Does Carbon Fiber Conduct Electricity?

4. Does carbon fiber conduct electricity as well as metal?

Does carbon fiber conduct electricity as well as metal? Metals such as silver, copper, and aluminum exhibit excellent electrical conductivity. The electrical conductance of these metals generally falls within the range of 35 X 10^6 to 62 X 10^6 S/m.

In contrast, carbon fibers possess relatively low electrical conductivity, typically on the order of 10² S/m. However, by incorporating certain materials, the electrical conductivity of carbon fibers can be enhanced. This leads to an increase in electrical conductivity to the order of 10⁴ S/m.

Compared to metals, carbon fiber has relatively poor electrical conductivity. In fact, plain carbon fiber conducts electricity approximately 1000 times less effectively than most metals. Even when treated with other materials to enhance its conductivity, carbon fiber still falls short of metals in terms of electrical conduction. 

Metals like silver, aluminum, and copper, in particular, excel in conducting electricity and remain approximately 100 times more efficient than carbon fiber treated with effective electrical conductors.

To answer the question, "Does carbon fiber conduct electricity as well as metal?" the answer is no. Carbon fiber does not conduct electricity as well as metals due to its inherent properties. While carbon fiber has various advantages in terms of strength and weight, its low electrical conductivity makes it less suitable for applications that require high conductivity. However, this characteristic can be beneficial in applications where electrical insulation or lightweight conductive structures are required.

Does carbon fiber conduct electricity as well as metal?

5. How can we enhance the conductivity of carbon fiber?

Once we have successfully answered the question, "Does carbon fiber conduct electricity?" we come to understand that: While carbon fiber possesses excellent mechanical properties, its inherent electrical conductivity is relatively low. However, there are several strategies available to enhance the conductivity of carbon fiber.

Carbon Nanotube Incorporation

One of the most promising methods to enhance carbon fiber conductivity is through the incorporation of carbon nanotubes (CNTs). CNTs exhibit exceptional electrical properties, which can be transferred to the carbon fiber matrix when they are introduced during the fabrication process. The CNTs act as conductive pathways, improving the overall electrical conductivity of the carbon fiber composite.

Graphene Coating

Another effective approach involves coating the surface of carbon fiber with a layer of graphene. Graphene, a single layer of carbon atoms arranged in a two-dimensional lattice, possesses exceptional electrical conductivity. The deposition of graphene onto carbon fiber provides an additional conductive layer, enhancing the overall conductivity without compromising the fiber's mechanical properties significantly.

Doping Techniques

Doping is a widely used technique in enhancing the electrical conductivity of materials. In the context of carbon fiber, doping involves introducing foreign elements or compounds into the carbon structure to modify its electronic properties. Doping with materials such as metals, metal oxides, or conducting polymers can significantly improve the conductivity of carbon fiber.

Surface Modification

Surface modification techniques can also be employed to enhance the conductivity of carbon fiber. By modifying the surface chemistry, one can promote better interfacial contact and electron transfer between adjacent fibers. Plasma treatment, chemical functionalization, and electrochemical oxidation are some of the methods used to modify the surface of carbon fiber and improve its conductivity.

Carbon Fiber Orientation

The orientation of carbon fibers within the composite structure can also impact their conductivity. Alignment of carbon fibers in the direction of the desired electrical flow can improve the overall conductivity of the material. Techniques such as applying electric fields during the manufacturing process can facilitate controlled alignment and enhance the electrical conductivity.

How can we enhance the conductivity of carbon fiber?

6. Applications of conductive carbon fiber

With its exceptional electrical conductivity, high strength-to-weight ratio, and excellent thermal stability, conductive carbon fiber has found numerous uses across various industries.

Aerospace and Aviation Industry

Conductive carbon fiber plays a crucial role in the aerospace and aviation industry. It is commonly used in the manufacturing of aircraft and spacecraft components, such as wings, fuselages, and structural reinforcements. The lightweight nature of carbon fiber, combined with its electrical conductivity, allows for improved fuel efficiency and lightning strike protection. 

Moreover, carbon fiber composites provide high strength, stiffness, and resistance to fatigue, ensuring the structural integrity of critical aircraft parts.

Automotive Sector

In the automotive sector, conductive carbon fiber finds applications in various ways. It is utilized in the manufacturing of lightweight body panels, chassis components, and interior trims. Carbon fiber-reinforced composites offer superior strength and durability, leading to reduced vehicle weight and improved fuel economy. 

Additionally, conductive carbon fiber is utilized in the development of advanced battery systems for electric vehicles, enhancing their overall performance and efficiency.

Applications of conductive carbon fiber

Electronics and Consumer Goods

The exceptional electrical conductivity of carbon fiber makes it ideal for applications in the electronics industry. It is used in the production of printed circuit boards (PCBs), connectors, and electromagnetic shielding. Carbon fiber-based PCBs provide better heat dissipation, electrical signal transmission, and increased mechanical strength compared to traditional materials. 

Furthermore, conductive carbon fiber is employed in consumer goods like smartphones, tablets, and wearables, where it enhances device performance and structural integrity.

Renewable Energy

Conductive carbon fiber plays a vital role in the field of renewable energy. It is utilized in the manufacturing of wind turbine blades, which require lightweight materials with high strength and stiffness. Carbon fiber composites offer superior fatigue resistance and durability, enabling more efficient wind energy generation. 

Additionally, conductive carbon fiber is used in the production of electrodes for fuel cells and supercapacitors, contributing to the development of clean and sustainable energy solutions.

Medical and Healthcare Applications

In the medical and healthcare sectors, conductive carbon fiber finds diverse applications. It is utilized in the development of prosthetic limbs and orthopedic implants due to its lightweight nature and excellent biocompatibility. Carbon fiber-reinforced implants provide strength and flexibility while minimizing stress on the patient's body. 

Moreover, conductive carbon fiber is employed in electrodes for neurostimulation and neural signal recording, facilitating advancements in medical diagnostics and treatments.

Applications of conductive carbon fiber

7. Conclusion

Does carbon fiber conduct electricity? Carbon fiber's electrical conductivity depends on its specific characteristics and manufacturing process. Carbon fiber composites are commonly used in various industries. Despite tending to have lower electrical conductivity than metals, when considering the electrical conductivity of carbon fiber, it is crucial to assess the intended purpose, requirements, and the specific composition of the material to determine its suitability for a particular application.

8. About European Plastic Company 

European Plastic Company (EuP) is the leading global manufacturer of filler masterbatch. With a wide range of products including filler, colorants, additives, engineering plastics, and bioplastics, EuP has established itself as a prominent player in the industry.

In 2019, EuP made its debut brand BiONext at the prestigious K fair, the largest plastics trade fair in the world, held in Germany. This marked a significant milestone for the company, laying the foundation for its export activities and establishing its presence on a global scale.

With 7 factories covering an area of dozens of hectares, With an annual production capacity of approximately 0.6 million tons, EuP demonstrates its commitment to meeting the demands of its customers worldwide.

At the forefront of technology, EuP employs advanced manufacturing processes to ensure the highest quality and performance of its products. The company's dedication to innovation has allowed it to maintain its position as a frontrunner in the market.

EuP boasts a modern laboratory system, equipped with cutting-edge facilities. This enables the company to conduct extensive research and development, ensuring that its products meet the strictest standards and exceed customer expectations.

A key factor in EuP's success is its team of highly skilled and passionate professionals. With their expertise and unwavering commitment, they drive the company forward, delivering exceptional products and services to customers worldwide.

EuP is one of the fastest-growing enterprises in Vietnam in 2023 (according to the VNR500 rankings).