Speciality fibres
A speciality fibre can be described as being a fibre with unique properties which make it the preferred fibre for particular applications. They are more expensive than the other synthetic fibres described in this document and are produced in comparatively small volumes. Statistics about the production and consumption of these fibres are not widely available.

There are very many speciality, or niche, fibres.

Aramids
Aramid is a contraction of aromatic and polyamide. BISFA defines these fibres as "fibre composed of linear macromolecules made up of aromatic groups joined by amide or imide linkages". There are two types of aramid: the meta-aramids and the paraaramids. The development of aramid fibres took place during the mid-50's to mid- 60's in the USA. The fibres were shown to have high melting points and high moduli. The impetus to develop the fibres came for the need for high performance fibres for air and space travel.

Production
The polymer polymphenyleneisophthalamide is used to make meta- aramids and the polymer polypterephthalamide to make paraaramids. Because the aramids decompose before they melt they are produced by wet and dry spinning methods. Sulphuric acid is the normal solvent used in the spinning processes. In wet spinning a strong solution of the polymer, which also contains inorganic salts, is spun through a spinneret into weak acid or water. In this bath the salts leach out. In the dry spinning process the salts are more difficult to remove and this process is only used to produce the weaker metaaramid fibres. In both processes post treatment of the fibres by additional drawing is used to optimise fibre properties. Aramid products are available as filament yarn, staple fibre or pulp.

Properties and End-Uses
Some of the main end-uses for meta-aramids are protective clothing, hot gas filtration and electrical insulation. Para-aramids are used to replace asbestos in brake and clutch linings, as tyre reinforcement, and in composites such as materials for aircraft, boats, high-performance cars and sports equipment. Members of police forces and armed forces wear anti-ballistic aramid apparel.