Surface characteristics of low-density polyethylene films modified by oxyfluorination-assisted graft polymerization

Effect of Oxyfluorination of PFA-Coated Metal Mesh with Superhydrophobic Properties on the Filtration Performance of SiO2 Microparticles

Recently, semiconductor wastewater treatment has received much attention due to the emergence of environmental issues. Acid-resistant coatings are essential for metal prefilters used in semiconductor wastewater treatment. Perfluoroalkoxy alkane is mainly used as an acid-resistant coating agent, since PFA has inherent superhydrophobicity, water permeability is lowered. To solve this problem, the surface of the PFA-coated metal mesh was treated via an oxyfluorination method in which an injected mixed gas of fluorine and oxygen reacted with the surface functional groups. Surface analysis, water contact angle measurement, and water permeability tests were performed on the surface-treated PFA-coated mesh. Consequently, the superhydrophobic surface was effectively converted to a hydrophobic surface as the PFA coating layer was surface-modified with C-O-OH functional groups via the oxyfluorination reaction. As a result of using simulation solutions that float silica particles of various sizes, the permeability and particle removal rate of the surface-modified PFA-coated stainless-steel mesh were improved compared to those before surface modification. Therefore, the oxyfluorination treatment used in this study was suitable for improving the filtration performance of SiO2 microparticles in the PFA-coated stainless-steel mesh.

Fluorine in the structure of polymers: influence on the gas separation properties

Results of studies on the separation of gases and vapours using fluorine-containing polymers are integrated and analyzed. Methods for the synthesis of these polymers are considered, including direct gas-phase fluorination, plasma polymerization of fluorine-containing precursors and modification of organic polymers, as well as diverse syntheses of monomers containing C−F and C−CF3 bonds and their subsequent polymerization. Structure – property relationships for these polymers are elucidated and their actual and potential applications as membrane materials are discussed.

The bibliography includes 165 references.

Modification of Polyethylene by RF Plasma in Different/Mixture Gases

Herein, low-density polyethylene (LDPE) films were treated using radio-frequency plasma discharge in the presence of air, nitrogen, oxygen, argon, and their mixtures to introduce new chemical functionalities. The surface properties of treated LDPE were qualitatively and quantitatively characterized using various analytical and microscopic techniques. It was found that the optimum plasma treatment for LDPE occurs in the presence of air plasma at an exposure time of 120 s and 80 W of nominal power. The plasma formed layer had tendency to increasing thickness with increasing treatment time up to 60 s using air and oxygen and even more with inert gases. An aging study of plasma-treated LDPE samples stored in ambient air or water medium revealed the partial hydrophobic recovery.

Efficient fluorinating agent through topochemical fluorination of Co-Fe layered double hydroxides

Mixed-metal inorganic fluoride, Co0.60Fe0.40F3, solid solutions are obtained through topochemical reactions of Co2FeCl(OH)6·2H2O LDH with molecular fluorine, F2, at temperatures as low as 100 °C. This solid solution possesses interesting F(•)-releasing ability, and its efficiency as a solid-state fluorinating agent is demonstrated on a commercial polyethylene film. (19)F solid state NMR and contact angle measurements underline the efficient fluorination of this polymer.