Poly esterification

AB-type polycondensations, 330 AB-type polymers, 135 Accelerated weathering tests, 245 Acceptor-catalytic polyesterification, 75 4-Acetoxy benzoic acid, poly esterification of, 74... 

Aromatic-aliphatic hydroxy acids, poly esterification of, 81 Aromatic-aliphatic polyesters, 32-35, 83 melting points of, 36 structure and properties of, 44-47 synthesis of, 69-71, 103-106 unsubstituted and methyl-substituted, 36-38... 

Dibasic acid monomers, 59 Dibasic acid poly esterifications, 17 Dibromo derivatives, 82 Dibutyltin dilaurate (DBTDL), 232 Dicarboxylic acid monomers, volatilization of, 72... 

Diol poly esterifications, 17 Diphenol monomers, 355 Diphenols... 

Diphenyl sulfone (DPS), 338 Diphenyl terephthalate-diphenyl isophthalate-bisphenol-A melt poly esterification, 111-112 Direct polyesterification, 63-69 Distinctness of image (DOI), 245 Divergent method, 8... 

The progress of polyester-forming reactions between glycols and dibasic acids is easily followed by titrating the unreacted carboxyl groups in samples removed from the reaction mixture. Simple esterification reactions are known to be acid-catalyzed. In the absence of an added strong acid, a second molecule of the acid undergoing esterification functions as catalyst. The rate of the poly esterification process should therefore be written... 

The extent to which one must drive the system in the forward direction can he seen by calculating the lowering of the small molecule concentration, which is necessary to achieve a particular molecular weight. For the poly esterification (Eq. 2-58) one can rewrite Eq. 2-59 as... 

In this study, polyesters [XII] having syringyl-type biphenyl units were synthesized from 4,4 -dihydroxy-3,3, 5,5 -tetramethoxybiphenyl (XI) which was prepared from 2,6-dimethoxyphenol (11). As shown in Scheme 6, poly esterification of XI with terephthaloyl, isophthaloyl and sebacoyl chloride were carried out by the low temperature solution polycondensation and by the interfacial polycondensation. The polyterephthalate with jjinh = 1.42 dl/g was obtained by the interfacial poly condensation. The polyisophtha-late with f7 nh = 0.73 dl/g and the polysebacate with Jj nh = 0.43 dl/g were obtained by the low temperature solution polycondensation. 

Tang and Yao [50] proposed a 2.5-order reaction scheme for poly esterification in the absence of catalysts. However, they were selective in the data points plotted, and the full plot departs considerably from linearity. The justification for the 2.5-order plot came from assuming that the reaction was proton-catalysed and that the proton arose from ionization of the acid... 

The free radical polymerization of styrene initialized by iniferter is influenced by chemical binding of iniferter on the surface of the silica." This reaction is used for grafting the polymer onto the surface of the silica. A similar approach is used when carbon whisker is incorporated during the graft-polymerization of methyl methacrylate. Depending on how the whisker is prepared, surface conversion can be increased up to twelve times compared to a polymerization with no whisker present. The addition of graphite to the poly esterification reaction doubles the molecular weight of the polymer. ... 

The rate of a step polymerization is most conveniently expressed in terms of the rate of disappearance of the reacting functional groups. Thus, the rate of poly esterification, Rp, can be expressed as the rate of disappearance of carboxyl... 

Kinetic data for the uncatalyzed equimolar poly esterification (Hamaim et al., 1968) of 1,10-decamethylene glycol and adipic acid at 161°C and 190°C are tabulated below. In this experiment, time and percentage of reaction were measured using, as a starting point, an equimolar mixture of the acid and alcohol dissolved in their ester. Thus, the extrait of reaetion at i = 0 was equal to 82%. 

Vaidya, U. R. Nadkami, V. M. Polyester polyols from glycolyzed PET waste effect of glycol type on kinetics of poly esterification. J. Appl. Polymer Sci., 1989, 38(6), 1179-1190. 

Development of completely different biomaterials from the existing commercially available five basic building blocks as sutures has been very rare. Barrows (1986,1994) introduced a new family of synthetic absorbable PEA polymer and fibers in 1990s. He made a series of nonamino acid-based PEAs from poly esterification of diols that contain preformed amide linkages, such as amidediols.The rationale for making PEAs is to combine the well-known... 

This article is a critical review of most of the literature relative to non-catalyzed, base-catalyzed, and miscellaneous-catalyzed epoxy-carboxy esterifications and poly esterifications. Most kinetic data are relative to model esterifications however, some polyesterification kinetics are analyzed. From the analysis of the results reported in the literature and found in our group it has been possible to compare and critize the various general mechanisms which have been proposed. 

Saint-Loup, R., R. Jean-Jacques, and B. Boutevin, Synthesis of Polyfethylene terephthalate)-block-Poly(tetramethylene oxide) Copolymer by Direct Poly esterification of Reactive Oligomers. Macromolecular Chemistry and Physics,... 

Nobel Prize winner Paul Flory studied the kinetics of several poly esterification reactions in a BR, on a laboratory scale. The experimental data of esterification of adipic acid with lauryl alcohol are given in the table below. Initial concentrations of the reactants were 1.0 mol/L. The reaction kinetics can be described with the rate expression... 

We do not yet have sufficient evidence to decide among these alternatives, but it is worth noting that phthalylation, which should closely parallel the conditions operating during poly esterification, gave substantially the same hydroxyl values as acetylation. 

It should be noted that ester-interchange reactions can take place at any stage during poly esterification, but they do not affect the molar mass distribution. This is because two molecules of random length react together to produce two more molecules and the total number of molecules in the mixture remains unchanged. 

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