Dimer acid-based polymers

All these studies show that many dimer acid-based polymers are based on the flexural and adhesion properties of dimer acid. A considerable amount of work has been reported on polyesters as well as other polymers. Among the polyesters based on dimer acid s versatile composition are those used to achieve high performance speciality polyesters. Efforts are made only to increase molecular weight little effort has been made to prepare polyesters of low molecular weight useful as plasticizers. A couple of references [88,89] describe the preparation of plasticizers comprising glycidyl esters of dimer acid and epoxy resin compositions containing them. 

Dimer acid-based polyesters being used as thermoplasts, thermoset, and elastomers are used in large quantities as adhesives and coatings. The polyesters, as we have reported herein, may have various commercial applications. Owing to the flexural properties, these low molecular weight linear polyesters of dimer acid may be used as plasticizers providing internal lubrication for various polymers, such as polyimides and inorganic coordination polymers, which may have very poor processibility. 

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. 

Oleochemical based dicarboxylic acids - azelaic, sebacic, and dimer acid (Figs. 4.5 and 4.6) - amount to ca. 100000 tonnes year-1 as components for polymers. This is about 0.5% of the total dicarboxylic acid market for this application, where phthalic and terephthalic acids represent 87%. The chemical nature of these oleochemical derived dicarboxylic acids can alter or modify condensation polymers, and, used as a co-monomer, will remain a special niche market area. Some of these special properties are elasticity, flexibility, high impact strength, hydrolytic... 

The salt is formed by hydrogen bonding and is usually in a polymer state (BHA) . The bond between BH and A is ionized to various degrees, from lion-ionized (BH...A) to completely ionized (BH+...A ) . The ionization becomes more pronounced with increasing acid-base interactions. When acid HA forms a dimer (HA)2 in the inert solvent, as in the case of carboxylic acids in benzene, the salts denoted by B(HA)2 [(BH+...AT..HA), (AH...B...HA), etc.] are formed. 

Ad-C3-Ad and poly-VAd exhibited the monomeric fluorescence at about 320 nm in ethanol. This finding suggests that the excimer was not formed for both dimeric and polymeric compounds in ethanol solution. Furthermore, the excimer could not be obtained either in the case of dimers or polymers of 6-methylaminopurine derivatives, though excimer emissions were observed in water-ethylene glycol. The absence of the excimer may be explained by the fact that the stacked forms of the nucleic acid bases are unstable in ethanol solution where the bases appear to be solvated with ethanol molecules23. ... 

Figure 4 BeCb structures (a) monomer, (b) dimer, and (c) polymer. Solid lines represent covalent bonds and arrowed lines represent coordinate (Lewis base — Lewis acid) bonds. Note that the depicted structure is in resonance with other formal electron placement schemes. Thus, on average, all Be-Cl interactions appear equivalent...

The synthesis of dimeric fatty acids is based on the reaction between a fatty acid with one double bond (oleic acid) and a fatty acid with two double bonds (linoleic acid) or three double bonds (linolenic acid), at higher temperatures in the presence of solid acidic catalysts (for example montmorillonite acidic treated clays). Dimerised fatty acids (C36) and trimerised fatty acids (C54) are formed. The dimer acid is separated from the trimeric acid by high vacuum distillation. By using fatty dimeric acids and dimeric alcohols in the synthesis of polyesters and of polyester polyurethanes, products are obtained with an exceptional resistance to hydrolysis, noncrystalline polymers with a very flexible structure and an excellent resistance to heat and oxygen (Chapter 12.5). Utilisation of hydrophobic dicarboxylic acids, such as sebacic acid and azelaic acid in polyesterification reactions leads to hydrolysis resistant polyurethanes. 

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. 

A. Kozlowska, R. Ukielski, New type of thermoplastic multiblock elastomers—poly(ester-block-amide)s—based on oligoamide 12 and oligoester prepared from dimerized fatty acid, Eur. Polym. J. 40 (2004) 2767-2772. 

Over the past several decades, polylactide - i.e. poly(lactic acid) (PLA) - and its copolymers have attracted significant attention in environmental, biomedical, and pharmaceutical applications as well as alternatives to petro-based polymers [1-18], Plant-derived carbohydrates such as glucose, which is derived from corn, are most frequently used as raw materials of PLA. Among their applications as alternatives to petro-based polymers, packaging applications are the primary ones. Poly(lactic acid)s can be synthesized either by direct polycondensation of lactic acid (lUPAC name 2-hydroxypropanoic acid) or by ring-opening polymerization (ROP) of lactide (LA) (lUPAC name 3,6-dimethyl-l,4-dioxane-2,5-dione). Lactic acid is optically active and has two enantiomeric forms, that is, L- and D- (S- and R-). Lactide is a cyclic dimer of lactic acid that has three possible stereoisomers (i) L-lactide (LLA), which is composed of two L-lactic acids, (ii) D-lactide (DLA), which is composed of two D-lactic acids, and (iii) meso-lactide (MLA), which is composed of an L-lactic acid and a D-lactic acid. Due to the two enantiomeric forms of lactic acids, their homopolymers are stereoisomeric and their crystallizability, physical properties, and processability depend on their tacticity, optical purity, and molecular weight the latter two are dominant factors. 

The most common application of vegetable oil-modified polyamides is in the surface coatings and paints industry. The dimer acids of tall and soybean oils and amines are used to modify the flow behaviour of paints. This thixotropic flow prevents setting and sagging, enables easy application and improves surface appearance. Vegetable oil-based nylons are used as engineering polymers in the automotive and transport industry for fuel lines. Products are also used for the extruded and moulded components of fuel systems such as filler necks, gas tanks, reservoir modules, filters, fuel rails and vapour recovery systems. Nylon 11 is also used in power coatings to coat metals that must withstand abrasion, impact and corrosion. 

Some important groups of polyanhydrides already in medical use are based on para-(carboxyohenoxy)propane, para-(carboxyphenoxy)hexane, para-(carboxyphenoxy) methane and their copolymers with sebacic acid. Also reported has been the use of fatty-acid-based polyanhydrides synthesized from hydrophobic dimers of erucic acid and sebacic acid in drug release applications [456]. They also follow surface erosion degradation [457]. As the polymer degrades, the fatty acid monomers deposit on the surface of the polymer matrices and act as an obstacle to the diffusion of low molecular weight compounds (e.g., active small molecules), contributing to slow release [458]. 

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