Ballooning, polyester fibers

The same polyester can be fabricated into a particularly strong film called Mylar. Mylar polyester film is used for the long-term protection of artwork and historical documents because of its transparency, strength, and inertness. Mylar is popular for its use in the manufacture of balloons for festive occasions. Mylar was also used to cover the 94-foot wingspan of the Gossamer Albatross, a human-powered aircraft used to fly the English Channel in 1979. Only two pounds of the polyester was needed to cover the entire wingspan, and the polyamide Kevlar was the material used for construction of the rudder of this aircraft In the United States, production of polyester fibers exceeds 3 billion pounds per year. 

For polyester, the fiber balloons (Figure 11a) before multiple splits are observed (Figure lib). Ballooning and splitting are followed by brushlike formations (Figure 11c) as the fiber breaks. Fibers with rounded tips can be observed (Figure lid). The rounded tips are... 

Polyesters may be formed by the reaction of a diol with a dicarboxylic acid or a dicarboxylate ester. In some older organic textbooks, you will find this referred to as a condensation polymer (because it is formed by a condensation reaction), but the polymer community frowns on this nomenclature. One such polymer is polyethylene terephthalate (PET) (Figure 21.18). Much of this is used in fibers for clothing and home furnishings. As a thin film. Mylar is used for survival blankets and balloons, as well as thermal and electrical insulation, food and drink packaging, cine films, and musical and electronic equipment. The reaction involved is a transesterification (Figure 21.19). 

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