Dialkyl sebacate esters

The coefficients A and B along with their standard deviations sA and sB are shown in Table 8.3.1. Equation 8.3.1 is invalid for nitrilo- and acetylalkanes. Homologous series with multiple functional groups, such as dialkyl sebacate esters and triglyceride esters, have been studied by Kishore et al. [8]. 

The variety of substances used as additives in polymers is considerable. For example, the fillers may include china clay, various forms of calcium carbonate, talc, silicas (diatomaceous silica), silicates, carbon black, etc. The impact modifiers typically include other polymers. Plasticizers include certain polymers with low (oligomers), dialkyl phthalates, dialkyl sebacates, chlorinated paraffin waxes, liquid paraffinic fractions, oil extracts, etc. Heat stabilizers include heavy metals salts such as basic lead carbonate, basic lead sulfate, dibasic lead phosphite (also acting as a light stabilizer), dibasic lead phthalate, stearates, ricinoleates, palmitates and octanoates of cadmium and barium, epoxide resins and oils, amines, diphenylurea, 2-phenylindole, aminocrotonates. The antioxidants include tris-nonyl phenyl phosphite, 2,6-di-ferf-butyl-p-cresol (BHT), octadecyl-3,5-di-terf-butyl-4-hydroxyhydrocinnamate, etc. The UV stabilizers include modified benzophenones and benzotriazoles. Processing lubricants include calcium stearate, stearic acid, lead stearate, various wax derivatives, glyceryl esters and long-chain acids. Fire retardants include antimony oxide, some pyrophosphates, etc. 

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. ... 

Unactivated esters, typically alkyl esters, often show low reactivity toward lipase catalyst for transesterifications. In the case of the lipase-catalyzed polycondensation of dialkyl esters with glycols, the polymer of high molecular weight was not obtained. The molecular weight improved when vacuum conditions were used Mw reached more than 2 x 104 in the combination of diethyl sebacate and 1,4-butanediol catalyzed by lipase MM [30]. 

The acid-catalyzed equilibrium of a dibasic acid with its mono- and di-esters furnishes a means of preparation of alkyl hydrogen esters of most aliphatic a,o)-dibasic acids. A mixture of the acid and its dialkyl ester is refluxed with concentrated hydrochloric acid and dibutyl ether, and the add ester is isolated by fractional distillation or extraction techniques. Excellent directions are given for the acid esters of adipic, sebacic, and azelaic acids. 

Taking DOP as the reference standard of performance for low-temperature flex efficiency, other commercial plasticizers that are significantly better performers include linear dialkyl phthalates and alkyl esters of sebacic, azelaic, adipic, phosphoric, and epoxidized oleic acids. Significantly poorer performers are tricresyl phosphate, diphenyl phthalate, butyl benzyl phthalate, and branched dialkyl phthalates. 

A variety of external plasticizers have also been suggested for cyanoacrylates. Among these are alkyl esters of aliphatic monocarboxylic acids such as cyanoacetates aliphatic dicarboxylic esters, such as malonates, adipates, and sebacates triaromatic phosphates such as tricresyl phosphate acyl triesters of glycerine dialkyl alkylphosphonates and alkyl phthalates. Joyner and Coover state that limiting the plasticizer concentration to less than 5% will not retard the cure speed, from 5 to 20% will retard the cure rate, and over 20% plasticizer concentration seriously slows the cure rate of the adhesive. 

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