From Plastics Wiki, free encyclopedia
Fiber or fibre is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread. Fibers are of great importance in the biology of both plants and animals, for holding tissues together. Human uses for fibers are diverse. They can be spun into filaments, thread, string or rope. They can be used as a component of composite materials. They can also be matted into sheets to make products such as paper or felt. Fibers are often used in the manufacture of other materials.
Fibers used by man come from a wide variety of sources.
- Natural fibers include those produced by plants, animals, and geological processes. They can be classified according to their origin:
- Vegetable fibers are generally based on arrangements of cellulose, often with lignin: examples include cotton, linen, jute, flax, ramie, sisal and hemp. Plant fibers serve in the manufacture of paper and cloth.
- Animal fibers consist largely of particular proteins. Instances are spider silk, sinew, catgut and hair (including wool).
- Mineral fibers comprise asbestos. Asbestos is the only naturally occurring mineral fiber.
- Man-made fibers may come from natural raw materials or from synthetic chemicals.
- Many types of fiber are manufactured from natural cellulose, including rayon, modal, and the more recently developed Lyocell. Fiberglass and optical fiber, which are made from purified natural quartz, are also man-made fibers that come from natural raw materials.
- Synthetic fibers are a subset of man-made fibers, which are based on synthetic chemicals (often from petrochemical sources) rather than arising from natural materials by a purely physical process. Such fibers are quite often made from nylon, polyester, or acrylic polymers, although pure polyacrylonitrile fibers are used to make carbon fiber. More exotic fibers have strong bonding between polymer chains (e.g. aramids), or extremely long chains (e.g. Dyneema or Spectra). Elastomers can even be used, e.g. spandex.