Nylon is a synthetic fibre, chemically synthesised by polymerisation from long-chain adipic acid and hexamethylenediamine. The polycondensation product in molten condition is pumped through a spinning machine and the resultant filaments are cold-drawn to increase their length.
Nylon fibres are smooth, solid, cylindrical filaments of variable diameters. In cross sections they appear uniformly circular. In appearance they may be highly lustrous to dull white or coloured. The filaments are very strong in their tensile strength. Nylon fibres occur as staples or filaments or threads. when crimped, the staple form nylon resembles wool. Nylon fibres do not respond to any chemical tests, which are used to identify vegetable, animal or regenerated fibres. They are soluble in 5N hydrochloric acid and insoluble in acetone.
In surgical dressings Nylon is used for making non-absorbable sutures. It is also used for making filter cloths, sieves and syringes.