Polyester



  Polyester (aka polycarbonate and polybutyrate.

Polyester may be produced in numerous forms. For example, polyester as a thermoplastic may be heated and processed into different forms, e.g., fibers, sheets, and three-dimensional shapes. While combustible at high temperatures, polyester tends to shrink away from flames and often self-extinguishes.

Applications

Polyester is the most widely used manufactured fiber in the United States. Woven polyester fabrics are used for apparel and home furnishings. These include bed sheets, bedspreads, curtains and draperies. Polyester fiberfill is also used to stuff pillows, comforters and cushion padding.

Polyester fabrics sometimes have a "less natural" feel when compared to similarly woven fabrics made from natural fibers, e.g., cotton. However, polyester fabrics may exhibit other advantages over natural fabrics, e.g., improved wrinkle resistance. As a result, polyester fibers are often spun together with natural fibers, e.g., cotton, to produce a cloth with blended properties.  

Polyesters are also used to make bottles, films, tarpaulin, liquid crystal displays, holograms, film insulation for wire and insulating tapes.

Liquid crystalline polyesters are among the first industrially used liquid crystalline polymers. In general they have extremely good mechanical properties and are extremely heat resistant. For that reason, they can be used as an abradable seal in jet engines.

fiberglass laminating resins, and non-metallic auto-body fillers. Fiberglass reinforced unsaturated polyesters find wide application in bodies of yachts and as body parts of cars.

Polyester is also widely used as a finish on high-quality wooden products like guitars, pianos and vehicle/yacht interiors (Burns Guitars, Rolls Royce and Sunseeker are examples of companies that use polyester on their products). The thixotropic properties of the sprayable form of polyester make it ideal for use on open grain timbers as it can quickly fill the grain and has a high build film thickness per coat. The cured polyester can then be sanded and polished to a high-gloss, durable finish.

Synthesis

Synthesis of polyesters is generally achieved by a polycondensation reaction. See "condensation reactions in polymer chemistry". The General equation for the reaction of a diol with a diacid is : (n+1) R(OH)2 + n R´(COOH)2 ---> HO[ROOCR´COO]nROH + 2n H2O

Azeotrope esterification

In this classical method, an alcohol and a carboxylic acid react to form a carboxylic ester. To assemble a polymer, the water formed by the reaction must be continually removed by azeotrope distillation.

Alcoholic transesterification

See main article on transesterification. 

          O
          \\
           C - OCH3  +  OH[Oligomer2]
          /
[Oligomer1]
\leftrightarrow 
          O
          \\
           C - O[Oligomer2]  + CH3OH
          /
[Oligomer1]
(ester-terminated oligomer + alcohol-terminated oligomer)   (larger oligomer + methanol)

Acylation (HCl method)

The acid begins as an acid chloride, and thus the polycondensation proceeds with emission of hydrochloric acid (HCl) instead of water. This method can be carried out in solution or as an enamel.

Silyl method
In this variant of the HCl method, the carboxylic acid chloride is converted with the trimethyl silyl ether of the alcohol component; trimethyl silyl chloride is produced.

Acetate method (esterification)

Silyl acetate method

Ring-opening Polymerization

Aliphatic polyesters can be assembled from metallorganically.

References

  • Textiles, by Sara Kadolph and Anna Langford. 8th Edition, 1998.
v • d • e
Plastics

Polylactic acid (PLA)

Polyurethane (PU)

Polyoxymethylene (POM)

v • d • e
Fibers
Natural:Alpaca · Angora · Zylon
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Polyester". A list of authors is available in Wikipedia.