Polymers sebacic acid

Aqueous caprolactam is polymerized alone and in the presence of sebacic acid (S) or hexamethylenediamine (H).t After a 24-hr reaction time, the polymer is isolated and the end groups are analyzed by titrating the carboxyl groups with KOH in benzyl alcohol and the amino groups with p-toluenesulfonic acid in trifluoroethanol. The number of milliequivalents of carboxyl group per mole caprolactam converted to polymer, [A ], and the number of milliequivalents of amino groups per mole caprolactam converted to polymer, [B ], are given below for three different runs ... 

Diesters. Many of the diester derivatives are commercially important. The diesters are important plasticizers, polymer intermediates, and synthetic lubricants. The diesters of azelaic and sebacic acids are useflil as monomeric plasticizing agents these perform weU at low temperatures and are less water-soluble and less volatile than are diesters of adipic acid. Azelate diesters, eg, di- -hexyl, di(2-ethylhexyl), and dibutyl, are useflil plasticizing agents for poly(vinyl chloride), synthetic mbbers, nitroceUulose, and other derivatized ceUuloses (104). The di-hexyl azelates and dibutyl sebacate are sanctioned by the U.S. Food and Dmg Administration for use in poly(vinyl chloride) films and in other plastics with direct contact to food. The di(2-ethylhexyl) and dibenzyl sebacates are also valuable plasticizers. Monomeric plasticizers have also been prepared from other diacids, notably dodecanedioic, brassyflc, and 8-eth5lhexadecanedioic (88), but these have not enjoyed the commercialization of the sebacic and azelaic diesters. 

Other nylons are made by varying the molecular length of the diamines and the dibasic acids Nylon-fi. in u.ses sebacic acid (10 carbon atoms), nylon-11 uses an acid from castor oil, and nylon-12 uses butadiene. These variations decrease moisture absorption. Other variations use amines with a ring structure, e.g., the aromatic nylons to give polymers with softening points above 577 F,... 

Numbers that follow the word nylon denote the number of carbons present within a repeating unit and whether one or two monomers are being used in polymer formation. For nylons using a single monomer such as nylon 6 or nylon 12, the numbers 6 and 12 denote the number of carbons in caprolactam and laurolactam, respectively. For nylons using two monomers such as nylon 610, the first number, 6, indicates the number of carbons in the hexamethylene diamine and the other number, 10, is for the second monomer sebacic acid. 

Polymers are further defined based on the number of carbon atoms they contain. Thus, the PA based on 1,6-hexamethylene diamine and sebacic acid is named PA-6,10 and the polymer based on caprolactam, PA-6. Terephthalic and isophthalic acid units are coded T and I. Thus, PA-6,T represents the PA from hexamethylene diamine and terephthalic acid. 

PA-6,10 is synthesized from 1,6-hexamethylenediamine and sebacic acid, and PA-6,12 from 1,6-hexamethylenediamine and dodecanedioic acid. The melt synthesis from their salts is very similar to PA-6,6 (see Example 1). These diacids are less susceptible to thermal degradation.55 PA-6,10 can also be synthesized by interfacial methods at room temperature starting with the very reactive sebacyl dichloride.4 35 A demonstration experiment for interfacial polycondensation without stirring can be carried out on PA-6,10. In this nice classroom experiment, a polymer rope can be pulled from the polymerization interface.34... 

In disc form, when prepared by compression molding, the more hydrophobic polymers, PCPP and PCPP-SA, 85 15, displayed constant erosion kinetics over 8 months. By extrapolation, 1-mm-thick discs of PCPP will completely degrade in over 3 years. The degradation rates were increased by copolymerization with sebacic acid. An increase of 800 times was observed when the sebacic acid concentration reached 80%. By altering the CPP-SA ratio, nearly any degradation rate between 1 day and 3 years can be achieved (4). 

Alkyl esters often show low reactivity for lipase-catalyzed transesterifications with alcohols. Therefore, it is difficult to obtain high molecular weight polyesters by lipase-catalyzed polycondensation of dialkyl esters with glycols. The molecular weight greatly improved by polymerization under vacuum to remove the formed alcohols, leading to a shift of equilibrium toward the product polymer the polyester with molecular weight of 2 x 10" was obtained by the lipase MM-catalyzed polymerization of sebacic acid and 1,4-butanediol in diphenyl ether or veratrole under reduced pressure. ... 

A polycondensation reaction of 4,4 -dihydroxybiphenyl, sebacic, and m-carboranedicarboxylic acids was reported to produce a carborane-containing polymer (142) (Fig. 78) that led to the production of a new columnar phase at elevated temperatures.157 This new phase was formed in addition to the crystalline and liquid crystalline smectic phases typically formed from only 4,4 -dihydroxybiphenyl and sebacic acids. 

Polyanhydrides based on unsaturated and fatty acid-derived monomers are shown in Table III. Poly(fumaric acid) (PFA) was fist synthesized by Domb et al. (1991) by both melt polycondensation and solution polymerization. The copolymer of fumaric acid and sebacic acid (P(FA-SA)) has been synthesized and characterized (Domb et al., 1991 Mathiowitz et al., 1990b). The mucoadhesive properties of this polymer... 

Erdmann and Uhrich (2000 Erdmann et al., 2000) recently synthesized novel poly(anhydride-co-ester)s containing salicylic acid in the backbone, by melt polycondensation of the disalicylic acid ester of sebacic acid, poly[bis(o-carboxyphenoxy)sebacate] (PCPS) and the copolymer P(CPH-CPS). The release of salicylic acid (the active form of aspirin) from the former was studied in vitro and from the latter was studied in vivo (Erdmann and Uhrich, 2000 Erdmann et al., 2000). Similar polymers that release 5-amino salicylic acid, and p-nitro salicylic acid have been prepared... 

A 100% natural polymer based entirely on agricultural products, the polyester elastomer obtained by reacting castor oil with a castor oil derivative, sebacic acid, was the basis for the synthesis of SIN s. 

PCCS and PTCS are synthesized by condensation of the corresponding c/s and Vans isomers of 1,4-cyclohexanedimethanol with sebacic acid. Values of the mean-square dipole moments of both polyesters are determined from dielectric constant measurements on dilute solutions of the polymers in benzene. Theoretical calculations carried out with the RIS model give values of d (In 0) / d Tin very good agreement with the experimental results. Fair agreement between theory and experiment is also found in the case of the dipole moments of the chains. 

The conditions used for a radical reaction could require a modification of the mechanochemical polycondensation. Such a polycondensation of poly ( -caprolactam) was carried out using sebacic acid dichloride as a condensing agent. For the mechanochemical polycondensation of all the other polymers, aliphatic and aromatic diamines were used. In all cases, the reaction was followed by determining chemically linked nitrogen, which decreased in the first case (owing to the fixation of acid dichloride) and increased in the remaining ones because of the reactions with diamines. 

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... 

Polyanhydrides have been modified by incorporating amino acids into im-ide bonds. The imide with the terminal carboxylic acids is activated with acetic anhydride and copolymerized with sebacic acid or CCP. Poly(anhydride-imides) increase the mechanical properties of the polyanhydrides. Degradation of poly(anhydride-imide)s is similar to that of polyanhydrides (i.e., surface erosion). Two different cleavable bonds (anhydride and ester) in the polymer chains have been included in polyanhydrides. Carboxylic acid-terminated e-caprolactone oligomers or carboxylic acid-terminated monomers (e.g., salicylic acid) have been polymerized with activated monomers (e.g., SA). 

Polyanhydrides, such as poly[bis(p-carboxyphenoxy)propane sebacic acid] copolymers (Figure 4.14), are also used for the fabrication of biodegradable implants. Polymer degradation occurs via hydrolysis, the biscarboxyphenoxypropane monomer is excreted in the urine and the sebacic acid monomer is metabolized by the liver and is expired as carbon dioxide via the lung (Figure 4.14). 

Which one of the following polymers undergoes homogeneous bulk erosion (a) Poly(lactide-co-glycolide) (b) Poly[bis(p-carboxyphenoxy)propane sebacic acid) (c) Poly(ortho esters) and/or (d) Poly(ethylene-vinyl acetate). 

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