Aliphatic polyamides sebacic acid

Figure 18.10. Melting points of polyamides from aliphatic diamines A, with adipic acid, B, with sebacic acid. (After Coffmann et al )...

Polyamides from diamines and dibasic acids. The polyamides formed fi om aliphatic diamines (ethylene- to decamethylene-diamine) and aliphatic dibasic acids (oxalic to sebacic acid) possess the unusual property of forming strong fibres. By suitable treatment, the fibres may be obtained quite elastic and tough, and retain a high wet strength. These prpperties render them important from the commercial point of view polyamides of this type are called nylons . The Nylon of commerce (a 66 Nylon, nam after number of carbon atoms in the two components) is prepared by heating adipic acid and hexamethylenediamine in an autoclave ... 

The two homologous aliphatic diamines are commonly used as bifunctional monomers for polycondensation reactions. Hexamethylenediamine or 1,6-diaminohexane, Cf,H16N2 (CAS No. 124-09-4, PM Ref.No. 1840), which is most well-known as a polyamide (Nylon 66) monomer, is also copolymerized with sebacic acid to form Nylon 6/ 10, or with isophthalic acid. Besides that, it is applied as a curing agent for expoxy... 

Other modifications of vegetable oils in polymer chemistry include the introduction of alkenyl functions, the study of novel polyesters and polyethers and the synthesis of semi-interpenetrating networks based on castor oil (the triglyceride of ricinoleic acid) [42], and also the production of sebacic acid and 10-undecenoic acid from castor oil [44]. Additionally, the recent application of metathesis reactions to unsaturated fatty acids has opened a novel avenue of exploitation leading to a variety of interesting monomers and polymers, including aliphatic polyesters and polyamides previously derived from petrochemical sources [42, 45]. 

Other Aliphatic Polyamides. They are mainly polyamides having longer polymethylene sequences. Their marketing was dictated by the need of technical polymers whose mechanical characteristics are less sensitive to the hygrome-try of the ambient conditions than those of PA-6 and PA-6,6. It concerns PA-6,10, which is obtained by the polycondensation between hexamethylenediamine and sebacic acid [HOOC-(CH2)8-COOH], PA-11 and PA-12. 

Primary amides, calciiun stearate, ethylene bis-stearamide, erucamide, fluoropolymers and silicones can be employed in polymers other than PVC. PTFE can also be used in polyamide processing, improving the friction and wear properties of gears and other engineering components. ABS and SAN benefit from the addition of zinc stearate or a secondary bis-amide, sometimes in combination with glyceryl monostearate or a fatty acid amine. Engineering plastics can be lubricated by secondary amides, aliphatic esters such as palmitates and sebacates, and silicones. 

---