Technical fiber is natural and manufactured fiber that is used for engineered applications. These applications often produce large business revenue globally and is seen in almost every contemporary building material for all applications ranging from construction to car manufacturing. This section is dedicated to technical fiber and will provide information on the types and structure of fiber, how technical fiber is produced and how to apply fiber to engineered applications. Furthermore, HempAlta has commissioned a detailed state of the art study on technical fiber and its applications.

History of Fiber Reinforcement

Fiber for structural reinforcement is not a new technology. It is known that the Mesopotamian’s were using straw to reinforce their clay bricks over 3500 years ago. Ancient mortars have even been reinforced with horse hair. Bast fibers, the fibers on the stem of some plants (hemp, flax, jute, kenaf, etc.) have been used for centuries (if not millennia), in clothing, construction and ropes.

Asbestos, found in everything from insulation to roof shingles, has been around since the early 1900s. In fact, though no longer used in much of the world due to their carcinogenic properties, asbestos is still used heavily in other parts of the world.

More recently, beginning around the 1960s, glass, steel and plastic fibers have become the standards for fiber reinforcement. Fiberglass is the most used fiber for reinforcement paneling, from storage tanks to boat hulls. Steel fiber is used primarily in concrete to increase impact resistance, and plastic fibers are used everywhere from clothing to concrete to body armor.

Carbon fiber is the most recent fiber reinforcement, primarily replacing high-end applications where glass fiber cannot be thin or light enough. Only recently available commercially (~2000), carbon fiber is used everywhere from sailboat masts to golf clubs to rocket ships.

Recently, within the last decade, sustainability has become a greater and impacting global issue; as a result, desire for displacement of non-renewable or energy-intensive fibers (i.e. glass, plastic, steel, carbon) by natural fibers (i.e. hemp, flax, wood, etc.) is of great interest to society.

Types of Fiber

There are numerous types of fiber, broken into two (2) primary categories; natural and manufactured. Natural fiber is sub-divided into two (2) segments; natural organic and natural inorganic.

Natural fibers can be extracted from plant, animal, insect, microbial (natural organic) and mineral sources (natural inorganic) and refined for apparel and industrial use.  There are 3 main classes of natural fibers based on source and chemical composition as follows:

  1. Cellulose Based:  organic, vegetable (plant) based fibers extracted from the fruit, leaf, seed or stem of the plant.  Some algae also produce cellulose fibers.  Cellulose is the most abundant polymer on earth.
  2. Protein Based: organic animal hair or insect secretions.
  3. Mineral Based: inorganic natural mined materials with an aspect ratio.

Of the over 100 plant types capable of supplying fiber, the most structural fiber come from those where extraction is from the stem. Due to the stem needing flexural strength against wind, these fibers such as hemp have evolved into the strongest natural fibers.

Manufactured fiber are fibers produced from fundamental constituent molecules in industrial process and are sub-divided into three (3) segments; regenerated natural, fiber that chemically absorb natural fiber materials then rebuilds the natural molecules (regenerate) into higher purity fibers with improved engineering properties, such as rubber. Synthetic organic, fiber that is manufactured from oil, gas, coal or agriculturally derived organic feedstock, such as polypropylene. Thirdly, inorganic synthetic, fiber that is manufactured from inorganic feedstocks that are usually produced from a mined sources such as fiberglass. The figure below provides a comprehensive list of commercially relevant fibers.

Forms of Fiber

  • Filament: A long continuous single fiber, such as fishing line.
  • Tow: A loosely bound, continuous bundle of many filaments with a large diameter. Tow is rarely used as a final product and is more commonly used as an intermediate fiber form before processing.
  • Staple: Short discrete fibers. Both natural and synthetic fibers are available in staple form. Synthetic staple fiber is formed by cutting filament or tow into uniform discrete staple lengths during mechanical processing. Natural fibers naturally form staple lengths and the final fiber size is determined by the plant type and degree of processing.
  • Yarn: There are two forms of yarn, filament and staple. Both yarns are a tight bundle in a continuous form. Filament yarn consists of a small number of continuous filaments twisted together into a rope-like structure. Staple yarn consists of short fibers twisted together into a chain-like structure with many frictional transition points along the surface area of the staple fibers. The process of converting staple fibers into yarn is generally referred to as spinning. Fiber in a yarn form is used to manufacture woven fabrics.
  • Whiskers: Also known simply as short fiber. Whiskers are short, discrete synthetic or mineral fibers directly formed into uncut discrete lengths, such as some synthetic ceramic and metal alloy fibers.