Weatherability of Melt-processible Fluoroplastics

Weatherability is defined as the retention of the general mechanical, chemical, electrical, and other physical properties when exposed outdoors for extended time periods. Good weatherability is important to the selection of materials for outdoor use. Sunlight, oxygen, moisture, and pollutants like acid gases can be destructive to plastic materials. The nature of attacks is by photodegradation, oxidative, and chemi- 

Fluoropol5uners, in general, have the ability to withstand continuous outdoor exposure. This resistance is due to the unique nature of carbon fluorine bonds that withstand oxidative, chemical, and photodegradation attack. Examples of the properties of fiuoropol5uners after outdoor or accelerated exposure are discussed in this section. 

Film Thickness, pm Years of Exposure Tensile Strength, MPa Break Elongation, % Tensile Modulus, MPa  

ETFE weathering data has been summarized in Table 3.74 94% of tensile strength and more than 84% of elongation has been retained after fifteen years of exposure in South Florida. The unexposed ETFE film transmitted 95.5% of visible light while the exposed film had a transmission of 93.7%. In other words, exposed film retained 98% of its original transmission. 

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