Properties and Characteristics of CFRPs
– CFRPs are composite materials consisting of a matrix and carbon fiber reinforcement.
– The matrix is typically a thermosetting plastic, such as polyester resin.
– CFRPs have directional strength properties and their properties depend on the layout of carbon fiber and its proportion to the polymer.
– The net elastic modulus of a composite material depends on the properties of carbon fibers and the polymer matrix.
– The fracture toughness of CFRPs is influenced by debonding, fiber pull-out, and delamination between sheets.
– Epoxy-based CFRPs exhibit high strength and elastic modulus but low plasticity.
– PEEK shows promise as an alternative polymer matrix with greater toughness and similar elastic modulus.
– Designing suitable strength safety margins is necessary due to the lack of a definable fatigue limit in CFRPs.
– Temperature and humidity can degrade the mechanical properties of CFRPs.
– Moisture plasticizes the polymer matrix, affecting properties like compressive and impact strength.
– CFRPs used for engine fan blades are designed to resist jet fuel, lubrication, and rainwater.
– Galvanic corrosion can occur when CFRP parts are attached to aluminum or mild steel.
– CFRPs are resistant to corrosion but can be affected by moisture at the matrix-fiber interface.
Manufacturing of CFRPs
– CFRPs are made from carbon filaments produced from precursor polymers like PAN or rayon.
– Precursor polymers are spun into filament yarns and then carbonized to produce carbon fiber.
– Unidirectional sheets or bidirectional woven sheets can be created from carbon fibers.
– The manufacturing process of CFRPs varies depending on the desired finish and production quantity.
– Some CFRP parts are created with a single layer of carbon fabric backed with fiberglass.
– Molding methods include layering sheets of carbon fiber cloth into a mold, filling the mold with epoxy, and curing.
– Vacuum bagging and autoclave-curing methods can be used for high-performance parts.
– Compression molding is a quicker process where mold components are pressed together with fabric and resin.
– Filament winding is used for difficult or convoluted shapes by winding filaments around a mandrel or core.
Applications of CFRPs
– Aerospace engineering: Airbus A350 XWB and A380 use CFRPs in wing spars and fuselage components.
– Aerospace engineering: CFRPs are used in micro air vehicles (MAVs).
– Automotive engineering: High-end racing cars extensively use CFRPs.
– Automotive engineering: McLaren F1 had the first carbon fiber body shell.
– Construction: CFRPs are used for retrofitting structures, seismic retrofitting, enhancing shear strength of reinforced concrete, strengthening circular columns, and lining pre-stressed concrete cylinder pipes.
– Carbon fiber microelectrodes are used for amperometry and fast-scan cyclic voltammetry in biochemical signaling.
– CFRPs are widely used in sports equipment such as racquets, kite spars, arrow shafts, and carbon fiber blades for amputee athletes.
– CFRPs are used in musical instruments, firearms, high-performance drones, and audio components.
– CFRPs can enhance fire resistance and are used in certain construction applications.
Disposal and Recycling of CFRPs
– CFRPs have a long service lifetime but cannot be melted down like metals.
– Thermal depolymerization in an oxygen-free environment can decompose CFRPs, allowing capture and reuse of carbon and monomers.
– Milling or shredding at low temperature can reclaim carbon fiber, but it weakens the recycled material.
– Zyvex Technologies introduced carbon nanotube-reinforced epoxy and carbon pre-pregs (CNRP) which are stronger and tougher than typical CFRPs.
– CNRP uses carbon fiber as the primary reinforcement and a carbon nanotube-filled epoxy as the matrix.
Cost, Durability Concerns, and Industrial Applications
– CFRPs are more costly than other commonly used materials in construction.
– CFRPs are considered to have superior properties compared to other fiber-reinforced polymers.
– Research is ongoing for retrofitting and alternatives to steel in construction.
– Concerns exist about the brittle nature of CFRPs compared to the ductility of steel.
– Lack of standardization and proprietary nature of fiber and resin combinations in the market.
– Chopped reclaimed carbon fiber can be used in consumer electronics and certain industrial applications that do not require the strength of full-length carbon fiber reinforcement. Source: https://en.wikipedia.org/wiki/Carbon_fiber_reinforced_polymer
Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon composite, or just carbon, are extremely strong and light fiber-reinforced plastics that contain carbon fibers. CFRPs can be expensive to produce, but are commonly used wherever high strength-to-weight ratio and stiffness (rigidity) are required, such as aerospace, superstructures of ships, automotive, civil engineering, sports equipment, and an increasing number of consumer and technical applications.
The binding polymer is often a thermoset resin such as epoxy, but other thermoset or thermoplastic polymers, such as polyester, vinyl ester, or nylon, are sometimes used. The properties of the final CFRP product can be affected by the type of additives introduced to the binding matrix (resin). The most common additive is silica, but other additives such as rubber and carbon nanotubes can be used.
Carbon fiber is sometimes referred to as graphite-reinforced polymer or graphite fiber-reinforced polymer (GFRP is less common, as it clashes with glass-(fiber)-reinforced polymer).
