Polyester materials

Polyesters were initially discovered and evaluated ia 1929 by W. H. Carothers, who used linear aliphatic polyester materials to develop the fundamental understanding of condensation polymerisation, study the reaction kinetics, and demonstrate that high molecular weight materials were obtainable and could be melt-spun iato fibers (1 5). 

The chemical resistance of polyester materials is well recognised to be limited because of the comparative ease of hydrolysis of the ester groups. Whereas this ease of hydrolysis was also observed in aliphatic polycarbonates produced by... 

Such is the diversity of polyester materials that it has to be stressed that their eommon feature is only the ester (—COO—) link and that this often only comprises a small part of the molecule. Nevertheless it may influence the properties of the polymer in the following ways ... 

Carbonyl compounds are everywhere. Most biological molecules contain carbonyl groups, as do most pharmaceutical agents and many of the synthetic chemicals that touch our everyday lives. Citric acid, found in lemons and oranges acetaminophen, the active ingredient in many over-the-counter headache remedies and Dacron, the polyester material used in clothing, all contain different kinds of carbonyl groups. 

One case is that of the TS polyester materials such as the alkyd molding compounds. 

Dicarboxylic acids or esters thereof are recovered from solid phase polyester materials, such as post-consumer products and factory scrap, by subjecting the polyester to at least two hydrolysis stages in at least the first of which the amount of water used is substantially less than needed to effect total conversion of the polyester to the dicarboxylic acid. Also the diol content is controlled in the course of carrying out the hydrolysis. The hydrolysis reactions may be preceded by reaction of the polyester with a diol, the resulting depolymerisation products then being hydrolysed. 

Polyester manufacture, organic titanium compounds in, 25 123 Polyester materials, recycling, 20 22 Polyester/polyether/polycarbonate,... 

PEN is considered to be a high-performance polyester material. The advantageous properties of PEN are derived from its chemical structure which contains both... 

Polyhydroxyalkanoate (PHA) is a biodegradable and biocompatible thermoplastic that can be synthesized in many microoiganisms from almost all genera of the microbial kingdom. Many microoiganisms synthesize polyhydroxyalkanoates (PHAs) as intracellular carbon and energy reserve materials [1]. These microbial polyesters materials are thermoplastics with biodegradable properties [2]. PHAs are usually accumulated... 

Dyes with releasable cationic groups are converted to water-insoluble dyes when heated in the dye bath. They can then enter textile materials that are amenable to dyeing with disperse dyes. Using this method, for instance, it is possible to dye polyester materials without having first to generate a finely dispersed form of the colorant with the aid of surfactants. An example of such a releasable group is the isothiouronium moiety [152], Dyes with isothiouronium groups are also suitable for wool [153],... 

Berndt H-J, Heidemann G, Fehlerursachen und Erkennungsmethoden von Farb-streifigkeit in Polyester-Material , Deutscher Fdrber-Kalender, 1972, 76, 408 79. 

Photographic film was once made from nitroeellulose, a plastic made from wood or cotton, without the use of hydrocarbons. Nitrocellulose film is strong and dimensionally stable. It made an excellent substrate for the photographic emulsion, but it is extremely flammable. Nitrocellulose in a slightly different form is used to make smokeless gun and rocket propellant. A replacement polyester material with the same dimensional stability has been produced from hydrocarbons. The polyester film has little... 

Lee et al. (1981) highlighted the importance of shear and elongational models for polyester materials. These models obey an Arrhenius temperature relationship however, it is assumed that there is no curing during flow. 

Thermoset injection moulding is a high-pressure process typically used for DMC or BMC polyester materials, and is shown in Figure 6.18. 

Polyesters are long chain synthetic polymers that have ester linkages. Polyester materials are nsed as fibers, plastics, and films in composites and elastomers and as coatings. They are tmly versatile materials. 

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