Carbon Fiber History and Applications

• Composite Materials and Structure-Property-Relationship

3 Carbon Fibers

• Carbon Fibers is the subject for this presentation

3.1 Content

• The presentation will cover the history of carbon fibers
• The presentation will cover the structure of carbon fibers
• The presentation will cover the manufacturing of carbon fibers
• The presentation will cover the properties of carbon fibers

3.2 Introduction to Carbon Fibers

• The presentation will cover the history of carbon fibers
• The presentation will cover the structure of carbon fibers
• The presentation will cover the application of carbon fibers
• The presentation will cover the market of carbon fibers
• The presentation will cover the characteristics of carbon fibers

3.2.1 History of Carbon Fibers (1/3)

• Carbon fibers were initially not used as reinforcement material
• The first incandescent electric lamps invented by Thomas Edison were made from cellulosic materials like bamboo, natural cellulose & cotton

3.2.1 History of Carbon Fibers (2/3)

• 1950: First oxidized PAN fiber "Orion" by DuPont
• 1959: First carbon fibers from PAN in Japan
• 1964: "Thornel 25" by Union Carbide (US) made from viscose rayon
• 1968: Royal Aircraft Establishment of Farnborough (RAE) given patent
• 1971: US production according to RAE patent by Hercules and Morganite
• 2009: JV SGL Group and BMW Group created SGL ACF

3.2.1 History of Carbon Fibers (3/3)

• Traditional Carbon was mainly electrodes using Fe, Al and Si for production and graphite parts for the solar & semi-conductor industry
• Modern Carbon is light in weight through CFRP (copyright by AIRBUS / BMW AG).
• Novel Carbon used Fullerenes in 1985, Nanotubes in 1991 & Graphene in 2004

3.2.2 Structure of Carbon Fibers

• Carbon fibers are fibers made from carbon-based precursors on a large scale
• Converted by pyrolysis into specific carbon structure with high tensile strength
• Since the 1970's carbon fibers are for reinforcing materials

3.2.2 Structure of Carbon Fibers

• High strength of carbon fibers are strong covalent bonds with a binding energy of 350 kJ/mol and highly oriented graphite structure

3.2.3 General Carbon Fiber Applications

• Aerospace is a market segment of carbon composites
• Automotive is a market segment of carbon composites
• Sports & Leisure are market segments of carbon composites

3.2.4 Carbon Fiber Market (1/3)

• Global annual production of crude steel was 1.62 billion tonnes, aluminum was 57.7 million tonnes and CFRP was 58 thousand tonnes in 2015
• The yearly carbon fiber capacity by region (2016); total:130,900t

3.2.4 Carbon Fiber Market (2/3)

• Graph showing carbon fiber capacities in 09/2019 by manufacturer
• Graph showing global carbon fiber demand 2010-2026

3.2.4 Carbon Fiber Market (3/3)

• In 2013 the global carbon fiber demand was 46500 t
• Aerospace & Defense accounted for 2%, Wind Turbines accounted for 7%, Sport/Leisure accounted for 5%, Molding & Compound 5%, Automotive 11%, Pressure Vessels for 12%, Civil Engineering for 14%, Marine for 14% and Other for 30%
• In 2013 the global carbon fiber revenue was US$ 1.7 billion
• Aerospace & Defense accounted for 1%, Wind Turbines accounted for 6%, Sport/Leisure accounted for 8%, Molding & Compound 4%, Automotive 4%, Civil Engineering for 11%, Marine for 9% and Other for 50%

3.2.5 Characteristics of Carbon Fibers

• Carbon fibers have low density [1.74 – 1.90 g/cm³]
• Negative thermal expansion coefficient [-0.5 to -1.1 10-6/°C]
• Negligible problems at inhalation of filaments less than 5 µm
• Anisotropic behavior in axial and transverse directions
• High modulus (especially pitch based)
• Good thermal stability (in absence of O2)
• High thermal conductivity
• High strength (especially PAN based)
• Excellent creep resistance
• High cost
• Low strain to failure
• Oxidation at temperatures greater than 450°C

3.3 Manufacturing of Carbon Fibers

• Carbon fiber manufacturing includes, the process chain, raw materials, manufacturing routes, and surface treatment & sizing

3.3.1 Process Chain

• Strong bonds of carbon atoms in hexagonal layers result in stiffness and tightness
• Carbon layers within the fiber are arranged along the fiber direction
• Single, dense, thin fibers are 6-7 µm in diameter
• Carbon Fiber tow with 1.000-50.000 single fibers are clustered to allow cost efficient handling
• Classical Methods for Fiber Making are not suitable for Carbon

3.3.1 Process Chain

• Production starts with crude oil being converted to Acrylonitrile which becomes PAN C Fiber Precursor and then Carbon Fiber, finally forming Composites Materials

3.3.1 Process Chain – Polymerisation

• Polymerisation features, Solution, dispersion, or precipitation polymerisation
• To form Poly Acrylo Nitrile solvent must be added
• The solvents can be organic and include DMAC, DMF, DMSO, inorganic [ZnCl2, NaSCN] and the quality demands extreme purity

3.3.1 Process Chain – Spinning

• Fiber is formed in the spinning bath
• Fibre are put through stretching for the orientation of molecules, washed, dried and wound
• Fibre structure develops during spinning and all defects reduce tenacity of carbon fiber

3.3.1 Process Chain – Stabilisation (Oxidation)

• PAN Fiber is white and flamable
• In Temperatures between 220-280°C oxidised PAN Fiber is black and non-flammable

3.3.1 Process Chain – Carbonisation (Graphitisation)

• Carbonisation features Gases and Temperature at » 1000°C
• Optimum tenacity is reached between 1300-1500°C forming HT, IM Fibers
• Continuous increase of stiffness with temperature at > 2000° forming HM Fibers

3.3.1 Process Chain - Surface Treatment & Sizing

• Surface Treatment includes Gases and Elektrolysis

3.3.2 Raw Materials

• Raw materials or precursors must exhibit sufficient carbon yield (> 50 wt.-%)
• Carbonized structure must show regions with graphitic layers
• Emerging structure must be oriented along covalent bonds to utilize high C-C binding energy

3.3.2 Raw materials

• Carbonaceous matter exhibits a theoretical carbon yield

3.3.2 Raw materials

• Polyester, Polyamide 6.6 raw material, is synthetic by Polycondensation
• Polyamide 6, Polyacrylonitrile, Polypropylene, Polyethylene, Polyvinyl chloride raw materials, are synthetic by Polymerisation
• Elastane raw material, is synthetic by Polyaddition
• Viscose Cupro, Acetate, Modal, Lyocell are man-made fibers which are a Cellulosic fiber

3.3.2 Raw materials

• Polyacrylonitrile(PAN) has a 50 % carbon yield
• Pitch has 80% carbon yield
• Lignin has a 40% carbon yield
• Cellulose has a 25% carbon yield

3.3.2 Raw materials

• Pan has a molecular formula of (C3H3N)n and a molecular weight of M = n x 53
• Share of carbon atomic mass is 36 and a theoretic carbon yield of 68 wt.-% with a Practical carbon yield of 50 wt.-%

3.3.2 Raw materials

• Carbon fibers can be produced from Isotropic pitch and Mesophase pitch (MPP):

3.3.2 Raw materials

• Lignin's Molecular formula is (C11H14O4)n, Molecular weight M = n x 210 and Share of carbon atomic mass of 132, with a theoretic carbon yield is 63 wt.-% and > 40 wt.-% Practical carbon yield

3.3.2 Raw materials

• Cellulose's Molecular formula (C6H10O5)n, Molecular weight M = n x 162 and Share of carbon atomic mass is 72, the theoretic carbon yield is 44 wt.-% with a Practical carbon yield of 25 wt.-%

3.3.3 Manufacturing Routes

• Carbon Fiber Production Using a PAN Based Precursor uses PAN Solution, PAN Precursor Fiber, Stabilisation, Carbonisation & Graphitisation

3.3.3 Manufacturing Routes

• Solution spinning requires wet spinning and is the standard process for carbon fiber precursor

3.3.3 Manufacturing Routes

• Alternative to solution spinning uses dry spinning but it is less efficient
• Melt spinning is in R&D phases
• Pseudo melt spinning is used by pilot in 80th

3.3.3 Manufacturing Routes

• PAN Precursor Production includes Spinning, Washing, Stretching and Drying

3.3.3 Manufacturing Routes

• Stretching of PAN Based Filament During Precursor Production is crucial for alignment of covalent bonds in longitudinal direction of future carbon fiber

3.3.3 Manufacturing Routes

• Stabilization features chemical reaction under oxidation, is irreversible, is highly exothermal (2-3x stronger than oxyhydrogen reaction), and need tension prevent shrinkage and tearing

3.3.3 Manufacturing Routes

• Stabilization requires, disentanglement of the polymer chains by externally applied stretching
• Additionally inner stretching due to shortening of the chemical bonds
• Stretching is dependent on reaction temperature and reaction progress

3.3.3 Manufacturing Routes

• Stabilization is applied in PANox fibers such as reinforcing carbon/carbon aircraft brakes, brake pads in automotive applications (replacement of asbestos) and for heat and flammability resistant insulation

3.3.3 Manufacturing Routes

• Target density from 1.36-1.42 to obtain fire-proof and infusible stabilized PAN fiber
• Oxygen content between 10 – 12% for maximum carbon yield
• Good alignment of is also important for Good alignment of C-C bonds along longitudinal fiber direction & Minimization of defects

3.3.3 Manufacturing Routes

• With increasing density of oxidized fiber carbon fiber density decreases
• The preferred density of oxidized fiber is 1.375 g/cm³

3.3.3 Manufacturing Routes

• Carbonization is conducted in a nitrogen atmosphere, uses thermal degration of non-carbon atoms, the formation of carbon rings and a mass loss of about 50%

3.3.3 Manufacturing Routes

• The formation of graphitic layers and reduction of layer distance is proportional to carbonization and the reduction of layer distance

3.3.3 Manufacturing Routes

• Garphitisation features a higher heat treatment in argon and improved orientation in Minimum strength (nitrogen loss) and lattice rearrangement

3.3.3 Manufacturing Routes

• Types of defects prohibit the formation of ideal graphitic structure

3.3.3 Manufacturing Routes

• Carbon Fiber Production Using a Pitch Based Precursor starts with Mesophase pitch (MPP), Pitch fiber, Thermoset MPP fiber, Carbon fiber, then Graphite fiber

3.3.3 Manufacturing Routes

• Young's modulus of carbon fiber increases with the degree of orientation of graphitic layers

3.3.3 Manufacturing Routes

• Pitch Based Fibers have properties of carbon fibers in longitudinal fiber direction
• PAN Based Fibers have properties of carbon fibers in longitudinal fiber direction

3.3.3 Manufacturing Routes

• Vapor Grown Carbon Fibers are produced by catalytic chemical vapor deposition (CCVD) and Nucleation of a filament by using a submicron with no stabilization needed

3.3.4 Surface Treatment and Sizing

• Surface treatment/Sizing requires, fiber-matrix adhesion for effective load transfer by the matrix between filaments
• Surface treatment is needed to increase number of active/reactive surface groups (mainly oxides) and roughen fiber surface to increase surface area
• Sizing or surface finish is used as a coating such as, Improvement of adhesion between filaments
• Facilitation in wetting out the fiber with matrix material and used as a lubricant to prevent fiber damage during subsequent handling processes
• Oxidix surface goups determine Carbon fiber is needed to be established

3.3.4 Surface Treatment and Sizing

• For surface Treatment oxidative Methods like, Anionic oxidation (electrolysis), Wet oxidation (chemical), Dry oxidation (chemical) are used
• It helps to supply of polar links (oxidic surface groups)

3.3.4 Surface Treatment and Sizing

• Sizing/Surface Finish requires Deposition from dispersion of a polymer
• The methods are, Electrodeposition of polymer on fiber surface, Electropolymerization of polymer on fiber surface & Plasma polymerization
• There must be, Good physical and chemical bonding of matrix to fiber surface
• Choice of sizing depends on future matrix material, Three-dimensional phase between fibers and matrix along with diffusion of matrix polymer into sizing, is used for interphase properties

3.3.4 Surface Treatment and Sizing

• Sizing/Surface Finish causes effects on the, surface that are, Compared by using Scanning Electron Microscopy (SEM) & Application of different sizes using identical matrix system

3.3 Carbon Fiber Properties

• This section will talk about fiber types and designation, comparison to other materials and specific carbon fiber applications

3.4.1 Fiber type and Designation

• In fibre type and Designation; Monofilament, Multi-filaments, low tow and heavy tow are discussed

3.4.1 Fiber Type and Application

• In fiber types HT is high tensile, IM is intermediate modulus, HM is high modulus and UHM is ultra high modulus

3.4.1 Fiber Type and Application

• HT & IM is produced by carbonization at temperatures between 1200-1400°C
• HM, UHM is has additional heat treatment (graphitization) at temperatures between 2000-3000°C

3.4.1 Fiber Type and Application

• In fibre types of HT, IM, HM, UHM; tensile strenght, youngs modulus and density are discussed

3.4.2 Comparison to Other Materials

• The properties of Wood, Steel, Aluminum, Carbon Fiber, Aramid Fibre, Glass Fibre and more are compared in terms of Density, Tesile strenght and Specific Tensile Strength

3.4.3 Specific Carbon Fiber Applications

• The use of carbon fiber include
• Aerospace such as Boeing 787 Dreamliner nose section and Airbus A350 XWB lower wing cover
• Automotive such as BMW i8 passenger compartment, A-piller Lamborghini and New BMW 7 series with carbon fiber reinforced parts

3.4.3 Specific Carbon Fiber Applications

• Specific Carbon fibers can be used for sports

A1 References (1/2)

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A1 References (2/2)

• A list of other references are displayed

Explore the evolution of carbon materials and their uses, from traditional applications to modern carbon fiber technology. This includes the discovery of carbon nanotubes and fullerenes, key patents, and the development and production milestones of carbon fibers.