Polymeric amide

Nylons, long-chain synthetic polymeric amides, are fabricated in many different types. The most commonly used forms are described in Table 3.46. 

Group of plastics comprised of resins that are primarily long-chain synthetic polymeric amides. Tliese have recurring amide groups as an integral part of the principal polymer chain. 

The first successful synthetic fibre. The term is applied to any long-chain synthetic polymeric amide and the best known commercial type is nylon 66 produced by the condensation polymerisation of adipic acid with hexamethylene diamine. 

Ex situ formation of (33) followed by addition to a mixture of CHCI3 and aldehyde (aliphatic or aromatic) in DMF at low temperature leads to deprotonation of CHCI3 but not of the aldehyde, and formation of the trichlorocarbinol takes place without formation of side products by aldol condensation, Scheme 21 [99]. The reaction could also be carried out (75-86% yield for butanal) using polymeric amides as a PB and with similar conditions [74]. 

The MWD is usually broader than the most probable distribution as a result of branching, which occurs in the later stages of reaction. As the monomer and lactam anion concentrations decrease, there is an increasing tendency for the polymeric amide anion XLII to attack the... 

Polymeric amides are found in nature in the many polypeptides (proteins) that constitute a variety of animal organisms and the composition of silk and wool. It was a search to prepare substitutes for the latter that led to the commercial development of the synthetic polyamides known as nylons. 

The reaction of dibasic acids with diamines was reported in the early literature [6-13] to give low molecular weight cyclic amides as infusible and insoluble products. It was Carothers [14-18] who first recognized that polymeric amides were formed by the reaction of diamines with dibasic acids. Many of the polyamides were able to be spun into fibers and the fibers were called Nylon by du Pont [14-20]. 

E.I. DuPont de Nemours and Company Water-Bearing Explosive Compositions Gelled with Polymeric Amide-Aldehyde and Method of Making Same... 

Purely linear polyethylene imine) may be obtained, however, by cationic polymerization of oxazolines (discussed in the next section), followed by the hydrolysis of the resulting polymeric amide. 

A variety of specific reactions are performed on polymeric amidic Mannich bases for instance, poly(maleimide), after aminomclhylation with aromatic amine, is subjected to a coupling reaction with a diazo derivative in order to obtain azo dyes, grafted onto the polymeric chain 439, which arc able to give colored chelates." ... 

Because of the greater basicity of the polymeric amid ion produced, a lactam anion is quickly reformed in a reaction identical to Eq. (25). Overall, the chain reaction is sustained by the continued reproduction of an imide and started by any imide producing reaction. 

A number of polyamide copolymers are known to have practical uses. The copolymers include those with different amides such as poly(caprolactam-co-laurolactam), poly(2,2,4-trimethyl-1,6-hexandiamine-co-2,4,4-trimethyl-1,6-hexandiamnie-co-1,4-benzendicarboxylic acid), poly(s-caprolactam-co-hexamethylene diamine-co-terephthalic acid), poly(hexamethylenediamine-co-terephthalic acid-co-isophthalic acid), etc. The addition of longer alkyl chains in an aromatic polymeric amide may improve some mechanical properties, but thermal resilience is in general reduced. For example, poly(hexamethylenediamine-co-m-xylylenediamine-co-isophthalic acid-co-terephthalic acid) starts decomposing at about 310° C, significantly lower than Nomex , for example. The same decrease in the decomposition temperature is seen for other mixed copolymers such as nylon 12 copolymers that include cycloaliphatic and aromatic segments. 

The chemical possibilities of tri- and tetracarboxylic systems are most interesting in the case of vicinal carboxylic groups which can react in unison. Such phtha-lic acid-type systems, mostly used as anhydrides, can serve as intermediates in the formation of high-performance polymeric amide-imides and polyimides (Pis). 

The polymeric amides, polyamides, are an especially important class of condensation polymers. Nylon is the best known polyamide. It is prepared by heating anhydrous hexa-methylenediamine with anhydrous adipic acid, a dicarboxylic acid. This substance is often called nylon 66 because the parent diamine and dicarboxylic acid each contain six carbon atoms. 

Fig. 5. Polymerizing amide formation catalyzed by mutant subtilisin E...

Poly(imino(1,6-dioxo-1,6-hexanediyl)imino-1,6-hexane-diyl). 126AM30P A 100 (polyamide) A 142 (nylon) A146 (nylon) A 153 (nylon) A 153P0118 A 175 (nylon) A 203 (nylon) A 205 (polyamide) A 216V35 A 216V50 1,8-Diazacyclotetradecane-2,7-dione homopolymer, sru Nylon-W Poly(imino(1,6-dioxo-1,6-hexanediyl)imino-1,6-hexanediyl) Ultramid A3 times G7. Polymeric amide formed by the reaction of adipic acid with hexylenediamine. Thermoplastic resin for injection molding, extrusion. Asahi Chem. Industry Snia UK. 

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