Re: Man-made vs. natural fibres
Posted 23 Jul 2007 21:03
Replying to [rawcotton]: As per you required please find here the details of fibers for your reference.
Natural fibers include those produced by plants, animals, and geological processes. They can be classified according to their origin:
Vegetable hi fibers are generally based on arrangements of cellulose, often with lignin: examples include cotton, linen, hemp jute, flax, ramie, and sisal. Plant fibers serve in the manufacture of paper and cloth.
Wood fiber, distinguished from vegetable fiber, is from tree sources. Forms include groundwood, thermomechanical pulp (TMP) and bleached or unbleached kraft or sulfite pulps. Kraft and sulfite, also called sulphite, refer to the type of pulping process used to remove the lignin bonding the original wood structure, thus freeing the fibers.
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 long mineral fiber. Short, fiber-like minerals include wollastinite, attapulgite and halloysite.
 Man-made fibers
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. Cellulose-based fibers are of two types, regenerated or pure cellulose such as from the cupro-ammonium process and modified or derivitized cellulose such as the cellulose acetates.
 Mineral fibers
The most well-known mineral fibers are glass and metal fibers.
Fiberglass made from specific glass formulas and optical fiber, made from purified natural quartz, are also man-made fibers that come from natural raw materials.
Metallic fibers can be drawn from ductile metals such as copper, gold or silver and extruded or deposited from more brittle ones such as nickel, aluminum or iron.
Carbon fibers are often based on carbonised polymers, but the end product is pure carbon.
 Polymer fibers
Polymer 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 made from:
PET or PBT polyester
polyvinyl alcohol fiber (PVOH)
polyvinyl chloride fiber (PVC)
polyolefins (PP and PE)
acrylic polymers, pure polyacrylonitrile PAN fibers are used to make carbon fiber by roasting them in a low oxygen environment. Traditional acrylic fiber is used more often as a synthetic replacement for wool. Carbon fibers and PF fibers are noted as two resin-based fibers that are not thermoplastic, most others can be melted.
Aromatic polyamids such as Twaron, Kevlar and Nomex thermally degrade at high temperatures and do not melt. These fibers have strong bonding between polymer chains
polyethylene (PE), eventually with extremely long chains / HMPE (e.g. Dyneema or Spectra).
Elastomers can even be used, e.g. spandex although urethane fibers are starting to replace spandex technology.
Coextruded fibers have two distinct polymers forming the fiber, usually as a core-sheath or side-by-side. Coated fibers exist such as nickel-coated to provide static elimination, silver-coated to provide anti-bacterial properties and aluminum-coated to provide radar chaff. Radar chaff is actually a spool of continuous glass tow that has been aluminum coated. An aircraft-mounted high speed cutter chops it up as it spews from a moving aircraft to foil radar signals.
There is also another fibre called MICRO FIBRE.