Nylon

Morphological structure

The morphology of nylon produced by melt spinning is characterized by a round cross-section and no special longitudinal structure, which can be observed under the electron microscope. Under the electron microscope, the filamentary protofibril organization can be observed, and the protofibril width of nylon 66 is about 10-15 nm. If a shaped spinneret is used, various kinds of nylon with special cross-sectional shapes can be made, such as polygonal, multilobed, hollow, and other shaped cross-sections. Its focusing state structure is closely related to the stretching and heat treatment in the spinning process. The macromolecular backbone of different nylon are connected by carbon and nitrogen atoms.

Shaped fibers can change the elasticity of the fiber, so that the fiber has a special luster and puffiness, and improve the fiber holding properties and covering ability and anti-pilling, reduce static electricity and other properties. Such as triangular fibers have a flash effect; five-leaf-shaped fibers have a fat light like luster, feel good, and anti-pilling; hollow fiber due to internal cavities, low density, good warmth.

Polyamide (PA, commonly known as nylon) is the U.S. DuPont developed for the fiber resin, industrialized in 1939. 1950s began to develop and produce injection molded products to replace metal to meet the downstream industrial products lightweight, cost reduction requirements. Polyamide main chain contains many repeating amide group, when used as a plastic called nylon, when used as a synthetic fiber we call nylon, polyamide can be produced by diamine and dibasic acid, can also be synthesized with ω-amino acids or cyclic lactams. Depending on the number of carbon atoms contained in the diamine and dibasic acid or amino acid, a variety of different polyamides can be produced. There are dozens of varieties of polyamides, among which polyamide-6, polyamide-66 and polyamide-610 are more widely used.

The chain link structures of polyamide-6, polyamide-66 and polyamide-610 are [NH(CH2)5CO], [NH(CH2)6NHCO(CH2)4CO] and [NH(CH2)6NHCO(CH2)8CO] respectively. Polyamide-6 and polyamide-66 are mainly used for spinning synthetic fibers called nylon-6 and nylon-66. nylon-610, on the other hand, is a thermoplastic engineering plastic with excellent mechanical properties.

PA has good overall performance, including mechanical properties, heat resistance, wear resistance, chemical resistance and self-lubricating, and low coefficient of friction, a certain degree of flame retardant, easy to process, suitable for glass fibers and other filler filler enhancement modification, improve performance and expand the range of applications.

PA's many varieties, PA6, PA66, PAll, PA12, PA46, PA610, PA612, PA1010, etc., as well as in recent years the development of semi-aromatic nylon PA6T and special nylon and many other new varieties. Nylon -6 plastic products can be used as the main catalyst, sodium metal, sodium hydroxide, etc., N-acetyl caprolactam as a co-catalyst, so that δ-caprolactam directly in the model through the negative ions of ring-opening polymerization and produced, known as casting nylon. This method facilitates the manufacture of large plastic parts.