Fatty acid-based poly anhydrides

Another class of PSA-fatty acid-based copolymers has been synthesized from the ricinoleic acid and ricinoleic half-esters with maleic and succinic anhydride, poly(sebacic-co-ricinoleic acid maleate), poly(sebacic-co-ricinoleic acid succinate), and poly(sebacic-co-12-hydroxystearic acid succinate) (P(SA-RAM), P(SA-RAS), and P(SA-HSAS)) (Krasko et al., 2003 Teomim et al., 1999). These syntheses result in poly(anhydride-co-esters). 

Recently, a new polyanhydride, poly(fatty acid-sebacic acid), has been synthesized. This polyanhydride uses hydrophobic dimers of erucic acid. Some of its physical properties relevant to the fabrication of drug delivery devices are also improved over those of the other anhydrides based on CPP lower melting temperature, higher solubility in solvents, and higher mechanical strength. The erosion of the polymers is dependent on... 

Vegetable oil-based poly(ester amide)s are formed by the polycondensation reaction of dihydroxy vegetable oil fatty amide with dibasic acid or anhydride. Thus oil-modified poly(ester amide) resins are amide-modified polyesters. As described in an earlier chapter, polyesters have long been used as a renewable resource for industrially important coating materials. However, most of these suffer from drawbacks such as poor alkali resistance, a long drying time and relatively low hardness. Because of the... 

Different types of chemical compounds such as vegetable oils, fatty adds, dibasic acids and anhydrides, dihydroxyamine and catalysts are required for the preparation of vegetable oil-based poly(ester amide)s. The methods of resinification or polymer formation are similar to those of vegetable oil-based polyesters, as discussed in the earlier chapter (Chapter 4). 

Vegetable oil-based poly(ester amide)s are prepared by a three-step reaction procedure in which a base such as sodium methoxide is used as the catalyst for the first two steps and metal oxide/hydroxide is used for the last step of the reaction (Fig. 5.2). In the first step, methyl esters of the fatty acids are produced by transesterifiction of oil with methanol, followed by transformation to dihydroxy fatty amide by amidation reaction with dihydroxyalkylamine and, finally, esterification reaction by treatment with dibasic acid or anhydride at a relatively high temperature to obtain the desired poly (ester amide). This may be done either by azeotropic distillation or by direct polycondensation under an inert atmosphere. Poly(ester amide) can also be synthesised at a low temperature through a condensation polymerisation reaction in the absence of an organic solvent. In this reaction, V,V-bis(2-hydroxyalkyl) fatty amide and dibasic anhydride are heated at a temperature lower than the onset of the melting points of the component. By-products, such as water, are removed by a vacuum technique. 

Vegetable oil-based poly(ester amide) resin has also been synthesised at a lower temperature in the absence of an organic solvent through a condensation polymerisation reaction of V,V-bis(2-hydroxyethyl) oil fatty amide and phthalic anhydride at a temperature lower than the onset of their melting points. By-products such as water were removed by a vacuum technique. Poly(ester amide) resins may also be prepared using an acid functional acrylic copolymer (butyl methacrylate and maleic anhydride) and hydroxy ethyl fatty amide of dehydrated castor oil in a 3 1 molar ratio. 

A few hyperbranched poly(ester amide)s have been prepared using a similar A2 + BBV approach, in which phthalic anhydride or maleic anhydride as an A2 monomer and diethanol amine as a BB 2 monomer were used. The polycondensation polymerisation technique is used to prepare the polymers. These poly(ester amide)s are modified by long alkyl chain (fatty acids) end groups. The dielectric properties of the modified polymers were investigated over a range of frequencies and temperatures. No relaxation peak was noticed in the dielectric spectrum at different temperatures. Castor oil and Mesua ferrea L. seed oil-based hyperbranched poly(ester amide)s are prepared using diethanol fatty amide of the oils with different types of anhydrides and dibasic acids with or without diethanolamine. 

Air drying poly(ester amide) resins were produced by the incorporation of phthalic anhydride in poly(styrene-co-maleic anhydride)-based room temperature cured poly (ester amide). This was prepared by the condensation reaction between AA -bis(2-hydroxy ethyl) linseed oil fatty amide and a copolymer of styrene and maleic anhydride in the presence of an acid catalyst (Fig. 5.5). ... 

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