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Electron Beam Processes
Published in Jiri George Drobny, Radiation Technology for Polymers, 2020
FEP, copolymer of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP), has physical and chemical properties similar to those of PTFE, but it differs from it in that it can be processed by standard melt processing techniques.
Halogen-Based FRs
Published in Asim Kumar Roy Choudhury, Flame Retardants for Textile Materials, 2020
Fluorinated ethylene propylene (FEP), a copolymer of hexafluoropropylene and tetra-fluoroethylene, is used prominently in wire insulation. It differs from the polytetrafluoroethylene (PTFE) resins in that it is melt-processable using conventional injection molding and screw extrusion techniques (Peter and Schmiegel, 2000).
Basic Materials Engineering
Published in David A. Hansen, Robert B. Puyear, Materials Selection for Hydrocarbon and Chemical Plants, 2017
David A. Hansen, Robert B. Puyear
Fluorinated Ethylene Propylene (FEP). FEP, also sold under the trade name of Teflon, has substantially the same chemical resistance as PTFE, but the maximum temperature limit is lower, 400°F (205°C). The primary advantage of FEP over PTFE is that it is melt processible. This permits the molding of complex geometries not easily obtained with PTFE. Common applications include liners for valves, lined pipe and liners for process equipment.
A power generation roadbed based on direct current triboelectric nanogenerators for human kinetic energy harvesting
Published in Journal of the Chinese Institute of Engineers, 2023
Baichuan Shan, Changxin Liu, Nanxi Chen, Jianhao Liu, Hao Sui, Huaan Li, Guangyi Xing, Runhe Chen
Although FEP has good power generation performance, it has poor abrasion resistance. PET has good abrasion resistance but poor power generation performance. Therefore, Kapton was finally selected as the material of the RFL for the device. The three materials were tested for wear resistance in the experimental system in Figure 4a, and the comparison of wear for Kapton, PET and FEP are shown in Figures 4b,c,d. As shown in Figure 4e, in a wear test experiment, using a maximum rotor speed of 300 r/min for continuous operation, the RFL made by KAPTON was able to generate a peak voltage of approximately 200 v after 100 h of continuous wear, and still keep a high performance.
Exploration of polyvinylidene difluoride (PVDF) for improvement of weathering resistance of textile substrates
Published in The Journal of The Textile Institute, 2022
Bharathi Dasaradhan, Biswa Ranjan Das, Thako Hari Goswami, Namburi Eswara Prasad
In recent years, many polymer coatings are used for protection of textile substrate from natural hazardous factors. Miklecic et al. (2015) studied the stability of acrylate coating with TiO2 and ZnO, after accelerated exposure. Similar studies were also done for other polymeric coatings like polyvinyl chloride and polyurethane for making them weather durable (Gesenhues, 2000; Mirabedini et al., 2011). The main problem with these organic polymeric coating is photo-oxidation, which lead to many changes like flaking, chalking, cracking, strength loss, etc. over time (Allen et al., 2004; Feldman, 2002). Hence, there is need for use of polymer, which is highly resistant to these changes over out-door exposure. Fluoro polymers are one such class of polymers that are used as protective coatings for many years. Their unique performance is due to the high bond strength of Carbon-Fluorine elements, which makes flouro polymers highly stable to environmental and chemical degradation. Fluoro polymer based coatings are known to give protection for more than 20 years compared to other coatings and this was proved by work of Razak et al. (2004), in which they evaluated the change in performance characteristics of polyvinylchloride (PVC) and polytetrafluoroethylene (PTFE) coated fabrics after subjecting to natural weathering of two years and was observed no degradation in PTFE coated fabrics. Fluoro polymers also possess other desirable attributes of coating; excellent chemical resistance, high abrasion resistance, high thermal stability, flame resistance, very low permeation to moisture and gases and low surface tension (Gardiner, 2015; Henry et al., 2018; Wood et al., 2000). Different fluoro polymers that are used for this kind of specified purpose include PTFE, fluorinated ethylene propylene (FEP) and perfluoroalkoxy alkanes (PFA). Polyvinylidene difluoride (PVDF) is the best fluoro polymer resin that has excellent weather resistance among other fluoro polymers (Teng, 2012). PVDF is a highly non-reactive and pure thermoplastic flouro polymer, which has alternating -CF2- and -CH2- units in its structure. Landry and Blanchet (2012) explored the significance of compounding PVDF with other conventional coating material for improvement of service life of light sensitive substrates. They compared the weather resistance performance of two different coating systems (PVDF-acrylic coating and acrylic coating) applied on similar wood species. Their results confirmed the resistance of PVDF to UV degradation in terms of colour change, atomic concentration and surface degradation (Landry et al., 2013). The ease of process-ability of PVDF compared to other fluoro polymers, both by melt and solvent processing, makes it a suitable candidate to be used as coating for protection of substrates from weathering degradation. Silagy et al. (2000) discussed in detail about the different technologies of application of PVDF as protective top coat on thermoplastic polymer substrates. In addition to excellent weatherability, PVDF based coating also possess other desirable characteristics like colour & gloss retention, self-cleaning and water repellency (Kumar et al., 2016).