Polyamides, Fibers

Abstract

Polyamide fibers are melt spun from linear semicrystalline thermoplastic polymers having recurring amide groups made from diamines and dicarboxylic acids or lactams. Poly(hexamethyleneadipamide), designated as nylon‐6,6, and poly(caprolactam), nylon‐6, account for 98% of the 4 million metric tons of the worldwide annual production of nylon fiber. The attributes of nylon such as high strength, durability, abrasion resistance, resilience, moderate hydrophilicity, ease of dyeability, and low specific gravity have been recognized since its introduction in 1938. Both the inherent properties and those properties that can be engineered into the fiber manufacturing and ultimately into the fabric in downstream mill processing combined with reasonable market pricing account for the diverse end uses and market longevity of nylon. Nylon fiber is offered in the forms of continuous flat and textured filaments, staple, tow and flock for hosiery, apparel, home, flooring, industrial and transportation fabric applications. The physical appearance, functionality, and end‐use performance of nylon fibers can be modified by incorporating additives, eg, delusterants, colorants, antioxidants, or antistats in the polymer, by designing a spinneret hole configuration to impart a desired luster, surface effect or specific dtex‐per‐filament, by spinning bicomponent or biconstituent fibers, and by chemically or mechanically treating the surface of the fiber or fabric.

Remote, Late-Stage Oxidation of Aliphatic C–H Bonds in Amide-Containing Molecules

“…1 Five- and six-membered ring lactams with N -alkyl chains uniformly provided remote 3° and 2° C—H bond oxidation products in high yields and selectivities (Table 2, 8−11). The inductive effect of the imidate salt enabled high site-selectivities for Fe(CF 3 PDP) 2 -catalyzed oxidation at alkyl substitution α to the amide carbonyl: cyclopentyl substituted 5- and 6-membered lactams were oxidized with Fe(CF 3 PDP) 2 at the methylene sites most remote from this electron-withdrawing moiety to furnish ketones 12 and 13 .…”

Heterocyclic monomers via reissert chemistry

“…Nitrogen‐containing polymers are a special class of materials that exhibit useful features. Polyamides1(a) and polyimides1(b,c) are useful in a variety of applications. Quaternary salt polymers are used as anion exchange resins, coatings, adhesives, ion conductors and in water treatment and coagulation 2.…”

“…Quaternary salt polymers are used as anion exchange resins, coatings, adhesives, ion conductors and in water treatment and coagulation 2. Aromatic nitrogen‐containing polymers, such as polyimides,1(c) polyquinoxalines, polyquinolines, polybenzimidazoles, polybenzothiazoles, and polybenzoxazoles, exhibit excellent thermo‐oxidative stability and retain useful mechanical properties at elevated temperatures for extended times 3…”

Synthesis of heterocyclic monomers via Reissert chemistry

“…Nitrogen‐containing polymers are a special class of materials that exhibit very useful features which can be attributed to (1) the basicity of the nitrogen atom(s), (2) hydrogen bonding 7 of N‐H moieties, and (3) quaternization. Polyamides, such as nylon‐6,6 and Kelvar™, possess remarkable strength due to hydrogen bonding between the carbonyl groups and the N H moieties and find applications in fibers and plastics 1111…”

“…Polyamides, such as nylon‐6,6 and Kelvar™, possess remarkable strength due to hydrogen bonding between the carbonyl groups and the N H moieties and find applications in fibers and plastics 111112.…”