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Adsorption onto Poly(tetrafluoroethylene) from Aqueous Solutions
Published in Kunio Esumi, Polymer Interfaces and Emulsions, 2020
Watson Loh, Josias R. Lopes, Antonio C. S. Ramos
Poly(tetrafluoroethylene) (PTFE) is the most successful example of such an approach. This polymer is prepared by polymerization of tetrafluoroethylene, producing a high-molecular-weight and mostly straight-chain polymer of formula -<CF2CF2)n-. This polymer was discovered in 1938 and some of its current commercial names are Teflon (DuPont), Halon (Allied Chemical), Fluon (ICI), and Hostaflon (Hoechst), among others. Other fluorinated polymers are commonly used as, for instance, hexafluoropropylene, fluoroethylpropyl-tetrafluoroethylene, commonly known as FEP-Teflon, or poly(vinylidene fluoride) (-(CF2CH2)n-).
Electrolyzer systems
Published in Leonard W. Casson, James W. Bess, Conversion to On-Site Sodium Hypochlorite Generation, 2019
Leonard W. Casson, James W. Bess
This fluoroelastomeric material is a copolymer of hexafluoropropylene and 1,1-difluoroethylene. It is suitable for all application areas of sodium hypochlorite systems. The temperature limits are -13°F (-26°C) to 350°F (176°C).
Characterization of PFAS air emissions from thermal application of fluoropolymer dispersions on fabrics
Published in Journal of the Air & Waste Management Association, 2023
Lindsay C. Wickersham, James M. Mattila, Jonathan D. Krug, Stephen R. Jackson, M. Ariel Geer Wallace, Erin P. Shields, Hannah Halliday, Emily Y. Li, Hannah K. Liberatore, Stanley (Mac) Farrior, William Preston, Jeffrey V. Ryan, Chun-Wai Lee, William P. Linak
Multiple studies have investigated the pyrolysis and destruction of PTFE at high temperatures (Ellis et al. 2001, 2003; Huber et al. 2009; Lewis and Naylor 1947) and several have examined the degradation of PTFE at temperatures commonly used to sinter PTFE to fabrics (Baker and Kasprzak 1993; Conesa and Font 2001; Ellis et al. 2001, 2003; Waritz and Kwon 1968). PTFE is stable up to 250°C, but above this temperature the polymer begins to slowly decompose by depolymerization (Huber et al. 2009). At 350°C, exposure to emissions causes polymer fume fever in humans, a temporary flu-like illness (Greenberg and Vearrier 2015; Waritz and Kwon 1968). At 375°C, emissions begin to show toxicity in animals, likely due to the perfluoroisobutylene (PFIB) and carbonyl difluoride emissions that have been reported (Treon et al. 1955). Between 400°C and 500°C, tetrafluoroethylene (TFE), fluoro-formaldehyde, hexafluoropropylene (HFP), and octafluorocyclobutane were also identified in the vapor phase (Ellis et al. 2003; Huber et al. 2009). However, these studies only examined the fluorinated polymer, not the complex chemical mixture contained in dispersions.
Reactivity of Al/CuO Nanothermite Composites with Fluoropolymers
Published in Combustion Science and Technology, 2022
Hongqi Nie, Sreekumar Pisharath, Huey Hoon Hng
In this paper, we aim to investigate the reactivity of Al/CuO nanothermite composites prepared with two commercial fluoropolymers; Viton (Diblock copolymer of Hexafluoropropylene and Vinylidene Fluoride) and THV (Triblock copolymer of Tetrafluoroethylene-Hexafluoropropylene-Vinylidene Fluoride). Viton and THV were chosen among the commercial fluoropolymers due to their high fluorine contents and excellent solubility in organic solvent (Wang et al. 2019). Compared to Al/fluoropolymer system, literature available on the study of fluoropolymer binder and nanothermite composite system are limited. It was reported (Kappagantula et al. 2012) that the reactivity of Al/molybdenum oxide (MoO3) nanothermite was improved, when Al that was surface functionalized with perfluorotetradecanoic (PFTD) acid was used as a fuel. On the other hand, a reduction in reactivity was exhibited by the Al/CuO nanothermite, when PFTD surface modified Al was used as a fuel (McCollum, Pantoya, Iacono 2015). These results clearly indicate that the Al fuel surface modified with a fluoro-compound influences the reactivity differently based on the nanothermite systems.
Investigation of the Burning Properties of Low-Toxicity B/CuO Delay Compositions
Published in Combustion Science and Technology, 2019
Jin-Shuh Li, Chien-Hung Lin, Chyi-Ching Hwang, Kai-Tai Lu, Tsao-Fa Yeh
The samples of boron (B) powder had two kinds of particle sizes, which were obtained from National Chung Shan Institute of Science and Technology (NCSIST) in Taiwan. The raw B powders were sieved through different grades of sieves in a vibratory sieving machine to obtain fine-B and coarse-B particles, and their particle sizes were nominally 3.0 and 6.0 μm, respectively. Copper oxide (CuO) powder was a reagent grade with an average diameter of about 9.0 μm and a purity of 99 %, which was purchased from Aldrich Chemical Co. Viton B was also obtained from NCSIST, which is a terpolymer of vinylidene fluoride (VF2), hexafluoropropylene (HFP) and tetrafluoroethylene (TFE) as a binder and can dissolve in the acetone and blend with other ingredients of the formula. Viton B and acetone (30:70 v/v) were mixed together to form a homogenous solution under stirring in advance, and then the B and CuO powders were dispersed in the solution to form a uniform slurry. The resulting slurry was used to prepare the cylindrical pellets.