Effects of catanionic surfactant mixture adsorption on the wettability of PTFE and PMMA

Hydrophilic Modification of Polytetrafluoroethylene (PTFE) Capillary Membranes with Chemical Resistance by Constructing Three-Dimensional Hydrophilic Networks

Polytetrafluoroethylene (PTFE) capillary membranes, known for the great chemical resistance and thermal stability, are commonly used in membrane separation technologies. However, the strong hydrophobic property of PTFE limits its application in water filtration. This study introduces a method whereby acrylamide (AM), N, N-methylene bisacrylamide (MBA), and vinyltriethoxysilane (VTES) undergo free radical copolymerization, followed by the hydrolysis-condensation of silane bonds, resulting in the formation of hydrophilic three-dimensional networks physically intertwined with the PTFE capillary membranes. The modified PTFE capillary membranes prepared through this method exhibit excellent hydrophilic properties, whose water contact angles are decreased by 24.3-61.2%, and increasing pure water flux from 0 to 1732.7-2666.0 L/m2·h. The enhancement in hydrophilicity of the modified PTFE capillary membranes is attributed to the introduction of hydrophilic groups such as amide bonds and siloxane bonds, along with an increase in surface roughness. Moreover, the modified PTFE capillary membranes exhibit chemical resistance, maintaining the hydrophilicity even after immersion in strong acidic (3 wt% HCl), alkaline (3 wt% NaOH), and oxidative (3 wt% NaClO) solutions for 2 weeks. In conclusion, this promising method yields modified PTFE capillary membranes with great hydrophilicity and chemical resistance, presenting substantial potential for applications in the field of water filtration.

Preparation and molecular simulation of an environmentally friendly dust-fixing agent based on chitosan-gelatin

In order to solve the hazard of coal mine dust, a dust-fixing agent (GC-TG-JFC) was prepared with gelatin, chitosan, octadecanol polyoxyethylene ether, and glutamine transaminase. The experimental conditions and the formulation were optimized by response surface method. The ratio of gelatin, chitosan, octadecanol polyoxyethylene ether, and glutamine transaminase was 0.405:0.211:0.095:0.286 and the dilution ratio was 1:30. The results of product performance test showed that the dust fixation rate could reach 99.95% when the wind speed was 9 m/s. The viscosity of the diluted solution was 42.5 mPa·s. The Forcite module in Materials studio software was used to analyze and calculate the radial distribution concentration, diffusion coefficient, and binding energy of the solution. The results showed that GC-TG-JFC migrated more water molecules to the surface of coal through the action of van der Waals force and hydrogen bond. In addition, the binding energy of water molecules increased and the diffusion coefficient decreased, which improved the binding ability of water molecules with coal. It could be found that GC-TG-JFC had good dust fixation performance by combining experiment and molecular dynamics method.