Fluorinated repellents application

Hydrocarbon-based repellents are relatively inexpensive but they repel only water. They do not impart oil and soil repellency to textiles. In contrast, fluorinated repellents provide oil and soil repellency as well as water repellency. However, the higher cost of fluorinated repellents limits their applications. To lower the cost of repellent finishing, fluoropolymers are usually coapplied with hydrocarbon-type repellents. With a hydrocarbon repellent as an extender, fluorinated repellents can be used at a lower concentration without an adverse effect on repellency [43-57]. 

PFCs comprise a large group of compounds characterized by a fully fluorinated hydrophobic linear carbon chain attached to one or more hydrophilic head. PFCs repel both water and oil, and are therefore ideal chemicals for surface treatments. These compounds have been used for many industrial applications including stain repellents (such as Teflon), textile, paints, waxes, polishes, electronics, adhesives, and food packaging [1]. 

Fluorinated polymers are considered high value-added materials, due to their outstanding properties which open up various applications [1-9]. Such polymers exhibit high thermostability and chemical inertness, low refractive index and coefficient of friction, good water and oil repellence, low surface energy and valuable electrical properties. In addition, they are non-sticky and resistant to UV, ageing, and to concentrated mineral acids and alkalies. 

Of a large number of possible fluorinated acrylates, the homopolymers and copolymers of fluoroalkyl acrylates and methacrylates are the most suitable for practical applications. They are used in the manufacture of plastic lightguides (optical fibers) resists water-, oil-, and dirt-repellent coatings and other advanced applications [14]. Several rather complex methods to prepare the a-fluoroalkyl monomers (e.g., a-phenyl fluoroacrylates, a-(trifluoromethyl) acrylic and its esters, esters of perfluoromethacrylic acid) exist and are discussed in some detail in [14]. Generally, a-fluoroacrylates polymerize more readily than corresponding nonfluorinated acrylates and methacrylates, mostly by free radical mechanism [15], Copolymerization of fluoroacrylates has been carried out in bulk, solution, or emulsion initiated with peroxides, azobisisobutyronitrile, or y-irradiation [16]. Fluoroalkyl methacrylates and acrylates also polymerize by anionic mechanism, but the polymerization rates are considerably slower than those of radical polymerization [17]. 

Also, fluorine-carbon composites were investigated as functional coating materials in a wide variety of applications coating materials for construction under low temperature environments [139], protective coating for computer hard disks [140], automotive components [141], semiconductor in opto-electronic devices [142, 143], and biomedical implants [144]. Those applications follow outstanding physicochemical, electrical and mechanical properties of these materials, (i.e., hardness, friction, water repellency, chemical... 

Perfluoroalkyl and polyfluoroalkyl substances (PEASs) are persistent organic pollutants with nearly ubiquitous occmrence in environmental samples. PEASs have anthropogenic origins over the period 1951 to 2004, it has been estimated that up to 7300 tons (i.e., 6.6 x 10 kg) of PEASs have been released into the environment [145]. PEASs are used in the manufacture of industrial materials and consmner products. The compounds are characterized by a nonpolar fluorinated hydrocarbon chain with a polar end group, and they exhibit both lipophobic and hydrophobic properties. Principal applications include uses as srufactants, nonstick coatings, and stain repellants. The compoimds are also precursors in the synthesis of fluoroelastomers and fluoropol)uners and are used in the... 

Very high grease and oil resistance together with water and alcohol repellency are obtained by fluorinated acrylic copolymers which are completely miscible in water. These products can be applied either by surface or by internal application. 

The characteristics of fluoropolymers are summarized in Table 1. Thermal and chemical resistance is in general with most of plastics, elastomers and perfluorinated membranes. Weather resistance with the outdoor durability for more than 20 years is specific for fluorinated paint resins. Surface properties such as water and oil repellency are provided by acrylic polymer-based textile finishes and coatings with long-chain per-fluoroalkyl groups. Electrical properties as well as a low refractive index are important for optoelectronics applications like optical fibers. 

Fluorinated materials such as zeolites, metal phosphates, and MOFs have been exploited for several applications such as water repellent and corrosion protecting surfaces. Moreover, the same materials have been used for the oil spill cleanup via selective adsorption... 

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