Dimer based polyamides

Chemistry of Dimer-Based Polyamide Resins Solid Polyamide Resins Properties... 

The most important coating appHcation for the nonreactive polyamide resins is in producing thixotropy. Typical coating resins such as alkyds, modified alkyds, natural and synthetic ester oils, varnishes, and natural vegetable oils can be made thixotropic by the addition of dimer acid-based polyamide resins (see Alkyd resins). Specialty high performance coating appHcations often requite the properties imparted by dimer acid components. 

As may be seen from the above structures, the dimer-based liquid polyamides and monomeric fatty amido amines contain free amine groups that are available for further reaction. One such reaction is imidazoline formation, which occurs intermolecularly (9), The structure of imidazoline can be indicated diagrammatically as follows. 

Certain specialty nylon resins with low melting temperatures have been used quite successfully with extrusion techniques. Both nylon and high-molecular-weight polyamide resins that are chemically related to dimer acid-based polyamides are used in high-strength metal-to-metal adhesives they are applied by extrusion. ... 

Low-melt-flow index dimer acid-based polyamide (Versamide) Aluminum 1.4-6.8(200-1,000) [27] ... 

Later, another supplier of dimer acid. Union Camp, introduced a variety of dimer acid-based polyamides under the trade name Uni-Rez (Table 4). 

Hexamethylenediamine (HMDA), a monomer for the synthesis of polyamide-6,6, is produced by catalytic hydrogenation of adiponitrile. Three processes, each based on a different reactant, produce the latter coimnercially. The original Du Pont process, still used in a few plants, starts with adipic acid made from cyclohexane adipic acid then reacts with ammonia to yield the dinitrile. This process has been replaced in many plants by the catalytic hydrocyanation of butadiene. A third route to adiponitrile is the electrolytic dimerization of acrylonitrile, the latter produced by the ammoxidation of propene. 

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. 

Polyamides can be made from renewable resources in several ways. Soybean-based dimer C36 fatty acids have been polymerized with a variety of diamines, including 1,4-phenylenediamine.183 Oxazolines, made from fatty acids and ethanolamine (12.32) have been polymerized up to a weight-average molecular weight of 148,000 with a poly-dispersity of 3.4.184... 

The solid fatty dimer polyamides are related to nylons and, indeed, are considered nylons when based on highly purified dimer acid (11). When based on a less pure version of dimer acid, they are, of course, of considerably lower molecular weight than nylons and have a much lower order of crystallinity. 

Fan, X.D. Y. Deng J. Waterhouse P. Pfromm. Synthesis and characterization of polyamide resins from soy-based dimer acids and different amides./. Appl. Polym. Sci. 1998, 68, 305-314. 

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