Nylon 6,6, structure synthesis

S. M. Aharoni, n-Nylons Their Synthesis, Structure and Properties, Wiley, New York, 1997. 

Lu, B. Chung, T.C. New maleic anhydride modified polypropylene copolymers with block structure synthesis and application in PP/nylon blends. Macromolecules 1999, 32, 2525. 

Ahorani SM. n-Nylons their synthesis, structure and properties. NY John Wiley Sons 1997. 

Ahai oni S M (1997) n-Nylons, their synthesis, structure, and properties, John Wiley Sons Ltd, Chichester. 

Figure 10. Effect of molar ratio of PCL and nylon on the biodegradability of CPAE by R. delemar lipase. The reaction time for each CPAE synthesis was k hours. The basic structures of nylon were of two types. One was - NH(0112) 0(left) the other was -jNH(CH2)5NHC0(CH2)nC0j-jn (right). Left nylon 6 (O) nylon 11(A) nylon 12 ( ) right nylon 6,6 (O ) nylon 6,9 (A) nylon 6,12 ( ). Assay conditions are the same as in the case of Figure 9 except CPAE was used in stead of CPE. (Reproduced from Reference IT. Copyright 1979 John Wiley ns Inc.)...

The surprising discovery that small oligo-P-peptides exhibit extraordinary tendencies to form stable secondary structures has led to rapid developments in the chemistry of these peptides. The earliest work in the field revolved around the synthesis of P-peptide polymers (the so-called nylon-3 derivatives). 2 Polymerization of P-amino acids led to polymers of undefined length. It was noted they could form stable structures but it proved impossible to gain any concrete information about the nature of those structures at that time. The developments in the synthesis of P-peptide oligomers of predefined length and advances in methods (i.e., NMR spectroscopy and X-ray crystallography) for the 3D characterization of such compounds has led to the discovery of new helical structures found to be adopted by a variety of P-peptides. I1,3-7 ... 

Positional isomerism is not generally an important issue in syntheses of polymers with backbones which do not consist exclusively of enchained carbons. This is because the monomers which form macromolecules such as poly(ethylcne terephthalate) (1-5) or nylon-6,6 (1-6) are chosen so as to produce symmetrical polymeric structures which facilitate the crystallization needed for many applications of these particular polymers. Positional isomerism can be introduced into such macromoicculcs by using unsymmetrical monomers like 1,2-propylene glycol (4-8), for example. This is what is done in the synthesis of some film-forming polymers like alkyds (Section 5.4.2) in which crystallization is undesirable. 

Carothers, Wallace H. (1896-1937). Born in Iowa, Carothers obtained his doctorate in chemistry at the University of Illinois. He joined the research staff of Du Pont in 1928, where he undertook the development of polychloroprene (later called neoprene) that had been initiated by Nieuland s research on acetylene polymers. Carothers s crowning achievement was the synthesis of nylon, the reaction product of hexamethylenetetramine and adipic acid. Carothers s work in the polymerization mechanisms of fiber like synthetics of cyclic organic structures was brilliant and productive, and he is regarded as... 

The nomenclature of step-reaction polymers is even more complicated than that of vinyl polymers and can be quite confusing. These polymers are usually named according to the source or initial monomer(s) and the type of reaction involved in the synthesis. For example, nylon 6,6 (4) is usually designated poly(hexamethylene adipamide), indicating an amidation reaction between hexamethylene-diamine and adipic acid. Nylon 6 is called either poly(6-hexanoamide) or poly(e-caprolactam). The former name indicates the structural and derivative method while the latter, which is more commonly used, is based on the source of the monomer. 

Thus muscle, collagen (in bone), keratin (in hair, nails and beaks) and albumin are all copolymers of very similar amino acids but have quite different physical properties. In deoxyribonucleic acid (DN A), the genetic template, the sequence of monomers is precise and variations are the cause of genetic mutations. Although the polypeptides are of ultimate importance in life processes they are not important in the context of materials and will not be considered further in this book. However, they have had a significant impact on modern polymer science since the synthesis of the first man-made polyamide fibre. Nylon, by Carothers was modelled on the structure of a silk, a naturally occurring polypeptide. 

A new composite material was introduced in 1987 with the discovery of a nylon-6/clay hybrid (NCH) [201]. The hybrid was prepared by the in situ thermal polymerization of s-caprolactam with 8% or less montmorillonite, the clay material containing 1-nm thick exfoliated aluminosilicate layers. It exhibited a truly nanometer-sized composite of nylon-6 and layered aluminosilicate. Figure 2.14 depicts conceptually the NCH synthesis and its fine structure. The NCH exhibited high modulus, high strength, and good gas-barrier properties. The unique and superior properties led to the commercialization of NCH. It has also created a new class of nanocomposites and worldwide interest. 

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