Diols polyesters from

Polyesters from diols and dicarboxylic acids (polyester fibres). 

Polymerisation of a diol with a dicarboxybe acid is exemplified by the production of a polyester from ethylene glycol and terephthabc acid either by direct esterification or by a catalysed ester-interchange reaction. The resulting polyester (Terylene) is used for the manufacture of fibres and fabrics, and has high tensile strength and resibency its structure is probably ... 

Titanium-cataly2ed ester interchange can be used to prepare polyesters from diester and diols as well as from diacids and diols at considerably higher temperatures. Polymer chains bearing pendant ester and hydroxy functions can be cross-linked with titanates. 

The polyols used are of three types polyether, polyester, and polybutadiene. The polyether diols range from 400 to about 10,000 g/mol. The most common polyethers are based on ethylene oxide, propylene oxide, and tetrahydrofuran or their copolymers. The ether link provides low temperature flexibility and low viscosity. Ethylene oxide is the most hydrophilic and thus can increase the rate of ingress of water and consequently the cure rate. However, it will crystallize slowly above about 600 g/mol. Propylene oxide is hydrophobic due to hindered access to the ether link, but still provides high permeability to small molecules like water. Tetrahydrofuran is between these two in hydrophobicity, but somewhat more expensive. Propylene oxide based diols are the most common. 

The carboxy-hydroxy reaction (direct esterification) is the most straightforward method of polyester synthesis. It was first reported in the 1930s by Carothers10 12 and is still a very widely used method for the synthesis of polyesters from diacids and diols (Scheme 2.12) or from hydroxy acids (Scheme 2.13). Direct... 

Trinitrochlorobenzene (piciyl chloride) in pyridine-A -mcthylpyrrolidi-none (NMP) solutions were later used for the preparation of polyesters from dicarboxylic acids and diphenols or aliphatic diols,309 but better results have been obtained with sulfonyl chlorides and phosphorus compounds. 

More recently, Heise and coworkers have shown that DKR can be combined with enzymatic polymerization for the synthesis of chiral polyesters from racemic secondary diols in one pot [34] (Figure 4.12). 

The enzymatic synthesis of polyesters from activated diesters was achieved under mild reaction conditions. The polymerization of bis(2,2,2-trichloroethyl) glutarate and 1,4-butanediol proceeded in the presence of PPL at room temperature in diethyl ether to produce the polyesters with molecular weight of 8.2 x 10. Vacuum was applied to shift the equilibrium forward by removal of the activated alcohol formed, leading to the production of high molecular weight polyesters. The polycondensation of bis(2,2,2-trifluoroethyl) sebacate and aliphatic diols took place using lipases BC, CR, MM, and PPL as catalyst in diphenyl ether. Under the... 

Wick, G. and Zeitler, H., Cyclic oligomers in polyesters from diols and aromatic dicarboxylic acids, Angew. Makromol. Chem., 112, 59 (1983). 

The formation of polyesters from a dialcohol (diol) and a dicarboxylic acid (diacid) is used to illustrate the stepwise kinetic process. Polymer formation begins with one diol molecule reacting with one diacid, forming one repeat unit of the eventual polyester (structure 4.3) ... 

Step polymerization proceeds by a relatively slow increase in molecular weight of the polymer. Consider the synthesis of a polyester from a diol and a diacid. The first step is the reaction of the diol and diacid monomers to form dimer ... 

Preparation of a Low-Molecular-Weight Branched Polyester from a Diol, a Triol and a Dicarboxylic Acid by Melt Condensation... 

Preparation of a High-Molecular-Weight Linear Polyester from a Diol and a Dicarboxylic Acid by Condensation in Soiution... 

Despite the improvements, a more durable elastomer was clearly needed. A battery of polyurethane elastomers including Pellethane were prepared and implanted subcutaneously in rats. Before implantation, the polymers were extruded into tubes and elongated over mandrels to 400%. The implants were left in place for 6 months and examined under a scanning electron microscope. One of the better performing polyurethanes was based on poly(l,6-hexyl 1,2-ethyl carbonate) diol. Polyesters typically are considered less durable due to the presence of esterase enzymes in vivo. From the data recovered during the implant period, it was determined... 

The fluorescence In dilute solution is measured for five polyesters with terephthalate as the rigid aromatic unit and diols derived from cyclohexane as the flexible spacer, A conformational analysis concludes that the spacers most conducive to excimer formation are the 1,3-c/s-cyclohexanediol and 1,4-e/s-eyclohexanedimethanol. This result from calculations is compatible with experimental results. 

The processes described in Table 2 present a peculiar interest in the working out of new materials as polyurethanes. These last polymers are very often based on macro diols coming from polyethers or polyesters, a-co functional polyolefins being relatively uncommon. Hence, Rhein and Ingham [139] prepared macrodiols by ozonization of polyisobutylene in CC14 at... 

Furthermore, Wall reviewed the fluorinated polyurethanes prepared from polyesters of fluorinated diols [79], from fluorinated polyethers [80] and detailed their properties [81]. 

Application New process to produce polyesters from the polyalkylene terephthalate family from terephthalic acid (PTA) or dimethyl terephthal-ate (DMT) and diols using the UIF proprietary two-reactor (2R) process consisting of tower reactor ESPREE and DISCAGE finisher or, alternatively a solid-state finishing. 

Fig. 1-30. Polyester synthesis from the carbonylative polycondensation of aromatic dibromides and diols (adapted from [237]).

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