the esterification of free fatty acids (ffa) with methanol is studied using sulfonated porous carbon (spc) as catalyst. in compare to the amorphous sugar catalyst and protonated nafion, the proposed catalyst shows stability and high efficient performance in biodiesel production. the highest initial rate of oleic acid conversion is obtained at catalyst loading of 1 mmol h+ and mole ratio of meoh...

The microphase separation of hydrated perfluorinated sulfonic acid membrane Nafion was investigated using Dissipative Particle Dynamics (DPD). The nafion as a polymer was modelled by connecting coarse grained beads which corresponds to the hydrophobic backbone of polytetrafluoroethylene and perfluorinated side chains terminated by hydrophilic end particles of sulfonic acid groups [1, 2]. Each f...

We present a detailed analysis of the nanostructure of the short side chain (SSC) perfluorosulfonic acid membrane and its effect on H(2)O clustering, H(3)O(+) and H(2)O diffusion, and mean residence times of H(2)O near SO(3)(-) groups based on molecular dynamics simulations. We studied a range of hydration levels (λ) at temperatures of 300 and 360 K, and compare the results to our findings in t...

Measurements of the mechanical and electrical properties of Nafion and Nafion/titania composite membranes in constrained environments are reported. The elastic and plastic deformation of Nafion-based materials decreases with both the temperature and water content. Nafion/titania composites have slightly higher elastic moduli. The composite membranes exhibit less strain hardening than Nafion. Co...

This nanorheological study addresses the water transport hindrance in perfluorinated ionomer membranes (Nafion® H+ form) in conjunction with structural relaxation properties of the polymer matrix. A low-temperature relaxation of the “dry” Nafion® matrix at 79 ◦C, about 35 ◦C below the glass transition temperature, was found to be responsible for a steady improvement of the water transport above...

The esterification of free fatty acids (FFA) with methanol is studied using Sulfonated Porous Carbon (SPC) as catalyst. In compare to the amorphous sugar catalyst and protonated Nafion, the proposed catalyst shows stability and high efficient performance in biodiesel production. The highest initial rate of oleic acid conversion is obtained at catalyst loading of 1 mmol H+ and mole ra...

The purpose of this study was to investigate the influence of electron beam (EB) irradiation on the structure and physical properties of Nafion 117 membranes (in both acid and sodium forms) when they are irradiated in water and isopropanol as solvents. The mechanical properties of Nafion membranes in acid form irradiated in water were found to rapidly deteriorate as the irradiation dose was inc...

A method of determining the connectivity of ion-conducting hydrophilic channels within the Nafion polymer electrolyte membrane by way of pore-directed nanolithography has been developed. Electrochemical etching of a silicon surface is performed through a Nafion-membrane mask. The resulting silicon surface imaged by tapping-mode atomic force microscopy (TMAFM) provides a footprint of the hydroph...