Chemical Properties
Most nylons exhibit a combination of high melting point, high strength, impact resistance, wear resistance, chemical inertness, and a low coefficient of friction.
Chemical Properties
d 1.18 g cm-2
History
The first nylon developed (type 6/6) was discovered in 1938 by W. H. Carothers.
Uses
nylons have filled an important role for industry and the consumer in various formulations, shapes, and forms, e.g., oriented fibers, which are subsequently processed into fabrics, fishing line, and other monofilament uses; injection-molded nylons, used as bearings, gears, and other parts subjected to wear and impact; extruded nylon tubing and hose, used in large quantity because of its chemical inertness, high strength, and flexibility; oriented nylon strip used as strapping for packaging, displacing traditional steel strapping; and heavy cast-nylon parts, frequently used in the textile, paper-making, and bottle-handling fields.
Uses
Tire cord; hosiery; wearing apparel component; bristles for toothbrushes, hairbrushes, paint
brushes (nylon 610); cordage and towlines for gliders; fish nets and lines; tennis rackets; rugs and
carpets; molded products; turf for athletic fields;
parachutes; composites; sails; automotive upholstery; film; gears and bearings; wire insulation; surgical sutures; artificial blood vessels; metal coating;pen tips; osmotic membranes; fuel tanks for automobiles.
Definition
Generic name for a family of polyamide polymers
characterized by the presence of the amide group
–CONH. By far the most important are nylon 66
(75% of U.S. consumption) and nylon 6 (25% of U.S. consumption). Except for slight difference in
melting points, the properties of the two forms are
almost identical, though their chemical derivations
are quite different. Other types are nylons 4, 9, 11,
and 12 (see Grade).
Safety Profile
Questionable carcinogen withexperimental tumorigenic data by implant. Reacts violentlywith F2. When heated to decomposition it emits toxicfumes of NOx
Properties and Applications
Polyamides thermoplastics are prepared by condensation by reacting a carboxylic acid (i.e., RCOOH) and an amine (i.e., R'NH2 ) giving off water. Hence, the basic monomer unit in polyamides is [—NH—(CH2 )2 —CO—]n. These resins are well known under the common trade name Nylon®. Owing to the wide diversity of different additives or copolymer as starting materials, there are several commercial grades of nylon resins available. each of them with particular properties. The main grades are nylon®6 and nylon®66, these being the two grades having the highest strength. Industrially, nylon 6 is obtained in a batch process by mixing caprolactam, water and ethanoic acid in a reaction vessel heated under inert nitrogen atmosphere at 230°C, while nylon 66 is prepared from adiponitrile, itself obtained from butadiene or propylene, which is converted into hexamethylene diamine (HMD). HMD is then reacted with adipic acid to yield nylon by a condensation reaction.
