Carbon fiber, known for its exceptional strength and low weight, has become a standard material across many modern industries. This composite material is typically made from thin strands of carbon atoms bound together in a crystal alignment and embedded in a polymer resin. Its unique properties offer superior performance compared to traditional metals, utilized in everything from spacecraft components to high-performance sporting goods. The history of this advanced material begins not with aerospace, but with the simple need for illumination.
The Earliest Carbon Filaments
The foundational concept of creating a fibrous material composed of carbon emerged in the late 19th century, driven by the race to perfect the incandescent light bulb. Thomas Edison began experimenting with carbonized filaments for the first practical electric light source in the late 1870s. His early successful designs, demonstrated publicly in 1879, used a thin strip of carbonized cotton thread or paper as the glowing element inside a vacuum-sealed glass bulb.
Edison’s team later found that carbonized bamboo slivers offered greater durability, making this the standard filament for his commercially produced bulbs for several years. These materials were carbon filaments, created by heating cellulose-based precursors in the absence of oxygen to prevent combustion. However, these rudimentary carbon products were used only for their electrical resistance and light-emitting properties. They were brittle and lacked the high modulus of elasticity and ordered atomic structure that characterizes modern structural carbon fiber. This early work established the technique of carbonizing organic matter, but the resulting material was a conceptual precursor to the high-performance fiber that emerged decades later.
Defining the Modern Material (1950s and 1960s)
The true birth of modern, high-performance carbon fiber occurred in the mid-20th century, following material science breakthroughs in the United States, Japan, and the United Kingdom. Early American research in the 1950s focused on rayon, a cellulose-based fiber, as the precursor material. Union Carbide began commercial production of rayon-based carbon fibers in 1959, leading to applications in the aerospace industry for rocket nozzles and heat shields. This initial material was structurally capable but had relatively low stiffness.
A significant advancement came in 1964 when Union Carbide researchers developed a “hot-stretching” process for rayon fibers. This technique involved stretching the fibers at extremely high temperatures (up to 2800°C), which aligned the internal graphite layers. This process increased the material’s modulus, or stiffness, by a factor of ten.
The most pivotal development came from Japan with the adoption of polyacrylonitrile (PAN) as a superior precursor material. Dr. Akio Shindo at the Osaka Technical Research Institute filed a patent application for creating PAN-based carbon fibers in 1959. PAN demonstrated impressive thermal stability, allowing it to retain a significantly higher percentage of carbon after high-temperature treatment compared to rayon. The resulting fiber exhibited far better tensile strength and a more efficient manufacturing process, shifting the industry toward PAN.
The United Kingdom made its own decisive contribution to high-modulus PAN fiber. Scientists at the Royal Aircraft Establishment (RAE) in Farnborough patented an improved, high-strength PAN-based process in 1963. This breakthrough was licensed to British companies, including Rolls-Royce, which applied the composite material to the compressor blades of its RB-211 jet engine in the late 1960s.
Scaling Up and Commercial Adoption
Despite the technological breakthroughs of the 1960s, carbon fiber remained an extremely expensive and specialized product, costing over $400 per pound initially. Production was limited, and early applications were restricted to state-sponsored defense and aerospace projects, such as military aircraft and NASA programs. The primary challenge during this period was moving the material from the laboratory to large-scale, cost-effective industrial production.
Pitch-Based Fibers
A third precursor material, pitch, was introduced in the 1970s, diversifying the market. Pitch-based fibers, derived from petroleum or coal tar, offer superior elastic modulus and thermal conductivity compared to PAN fibers. Although they generally have lower tensile strength, their unique properties made them suitable for niche applications requiring extreme stiffness or heat dissipation, such as aircraft brakes.
Manufacturing advancements and increased production capacity gradually lowered the cost, making the material accessible for wider use. Toray Industries began commercial production of its PAN-based carbon fiber, “Torayca,” in 1971, signaling readiness for broader markets. Commercial adoption accelerated significantly in the late 1970s and early 1980s, moving beyond military use into the consumer market. High-end sporting goods, including tennis rackets, golf club shafts, and fishing rods, became key early applications that showcased the fiber’s performance. This transition paved the way for its later integration into the automotive, wind energy, and civil engineering sectors.