Polyamides and derivatives

For a variety of reasons, a comprehensive review of the history, current developments and recent results in Du Pont research on aromatic polyamide membranes is not possible. In fact, this paper will be limited to Du Pont research and limited further to some key polyamides and derivatives that illustrate the relationship between structure-level and membrane properties. 

This brief historical summary of Permasep permeator developments introduces the subject of structure-property relationships for membranes from aromatic polyamides and derivatives. 

Various synthetic aromatic polyamides and derivatives have been prepared, principally for evaluation in high temperature applications. Some of these materials have found limited commercial use and are described in this chapter. 

Fluorinated diacids offer a convenient method for introducing a perfluoro moiety into organic molecules. They are of potential interest in the preparation of polyamides and other fluorinated polymers. A detailed description of the perfluorocarboxyUc acids and their derivatives has been pubflshed (1), and a review article on polyfluorinated linear biflmctional compounds has appeared (35). 

Phosphoric acid [7664-38-2] and its derivatives are effective catalysts for this reaction (60). Reverse alcoholysis and acidolysis can, in principle, also be used to produce polyamides, and the conversion of esters to polyamides through their reaction within diamines, reverse alcoholysis, has been demonstrated (61). In the case of reverse acidolysis, the acid by-product is usually less volatile than the diamine starting material. Thus, this route to the formation of polyamide is not likely to yield a high molecular weight polymer. 

Amines or amides Alkyl amines (iindecyloctyl and diamyl methyl amine) polyamides (acyl derivatives of piperazine) Boiler foam sewage foam fermentation dye baths... 

Whilst by far the bulk of polyamide materials are used in the form of fibres, they have also become of some importance as speciality thermoplastics of particular use in engineering applications. The fibre-forming polyamides and their immediate chemical derivatives and copolymers are often referred to as nylons. There are also available polyamides of more complex composition which are not fibre-forming and are structurally quite different. These are not normally considered as nylons (see Section 18.10). 

Closely related to the polyamides are the polyimides and derivatives such as polyamide-imides and polyether-imides. These are discussed in Sections 18.13 and 18.14. 

These materials are also often referred to as glass-clear nylons, which is different from the normal usage of the term nylon for fibre-forming polyamides and their immediate chemical derivatives. 

Recognition of DNA sequence and molecular design of artificial repressors, pyrrole-imidazole polyamides, and calicheamycin derivatives 97YGK384. 

Polyamides and Polyesters Step-Growth Polymers 818 21.10 Spectroscopy of Carboxylic Acid Derivatives 822... 

NOTE The above applies to composite polyamide and polyvinyl derivative membranes. Do NOT use chlorine, which is suitable only for cellulose acetate membranes. 

Figure 20. Diamantane-based polyamides (a) derived from 4,9-bis[4-(4-aminophenoxy)phe-nyljdiamantane and (b) derived from 4,9-bis(4-aminophenyl)diamantane. Taken from Ref [90] with permission.

In 1929 Carothers proposed a generally useful differentiation between two broad classes of polymers condensation polymers in which the molecular formula of the structural unit (or units) lacks certain atoms present in the monomer from which it is formed, or to which it may be degraded by chemical means, and addition polymers, in which the molecular formula of the structural unit (or units) is identical with that of the monomer from which the polymer is derived. Condensation polymers may be formed from monomers bearing two or more reactive groups of such a character that they may condense intermolecu-larly with the elimination of a by-product, often water. The polyamides and polyesters referred to above afford prime examples of condensation polymers. The formation of a polyester from a suitable hydroxy acid takes place as follows ... 

In polymer applications derivatives of oils and fats, such as epoxides, polyols and dimerizations products based on unsaturated fatty acids, are used as plastic additives or components for composites or polymers like polyamides and polyurethanes. In the lubricant sector oleochemically-based fatty acid esters have proved to be powerful alternatives to conventional mineral oil products. For home and personal care applications a wide range of products, such as surfactants, emulsifiers, emollients and waxes, based on vegetable oil derivatives has provided extraordinary performance benefits to the end-customer. Selected products, such as the anionic surfactant fatty alcohol sulfate have been investigated thoroughly with regard to their environmental impact compared with petrochemical based products by life-cycle analysis. Other product examples include carbohydrate-based surfactants as well as oleochemical based emulsifiers, waxes and emollients. 

There continue to be a few examples reported where rearrangement has been used synthetically to develop new products sometimes important in the industrial world. Monomers for polyamides and polyimides (which are used for making moisture sensitive films, fibres and mouldings) have been synthesized24 by the reduction of a nitro compound, followed by a benzidine rearrangement of the resulting hydrazobenzene derivative as outlined in Scheme 5. 

Of equally high industrial potential as intermediate chemicals are the various HMF-derived products for which well-worked-out, large-scale adaptable production protocols are available. Of these, the 5-hydroxymethyl-furoic acid, the 2,5-dicar-boxylic acid, the 1,6-diamine, and the respective 1,6-diol (framed in Scheme 2.12) are the most versatile intermediate chemicals of high industrial potential, as they represent six-earbon monomers that could replace adipic acid, alkyldiols, or hexamethy-lenediamine in the production of polyamides and polyesters. 

Munoz-Guerra and Galbis et al. have initiated in the past decade a systematic study of a series of sugar-based AABB linear polyamides. These polyamides are derived... 

Pyrazolines are a class of FBAs for use on cellulose acetate and more importantly commercially on polyamide fibres. For polyamide, anionic derivatives such as (3.62) are used, applied by pad-thermosol and related methods. 

High-performance ahybrid resins were prepared by Yamada et al. (1) having excellent heat resistance and thermal properties. These consisted of hyper-branched polyamide resins derived from the pyromellitic dianhydride with triamines such as 1,3,5-triamino benzene that were postreacted with... 

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