Effect of Process Conditions on the Properties of Resorcinol-Formaldehyde Aerogel Microparticles Produced via Emulsion-Gelation Method

Abstract

Organic aerogels in the form of powder, microgranules and microsized particles receive considerable attention due to their easy fabrication, low process time and costs compared to their monolithic form. Here, we developed resorcinol-formaldehyde (RF) aerogel microparticles by using an emulsion-gelation method. The main objective of this study is to investigate the influence of curing time, stirring rate, RF sol:oil ratio and initial pH of the sol in order to control the size and properties of the microparticles produced. The emulsion-gelation of RF sol prepared with sodium carbonate catalyst in an oil phase at 60 °C was explored. RF microparticles were washed with ethanol to remove the oil phase followed by supercritical and ambient pressure drying. The properties of the dried RF microparticles were analyzed using FT-IR, N2 adsorption isotherm, gas pycnometry, wide angle X-ray scattering and scanning electron microscope. RF microparticles with high surface area up to 543 m2/g and large pore volume of 1.75 cm3/g with particle sizes ranging from 50–425 µm were obtained.

Molecular-Level Tuning of Active Sites of the Carbonaceous Catalyst for Boosting Electrochemical H2O2 Production and its Application in Electro-Fenton-like Degradation of Organics

“…Further, increasing the DDA addition to 2.68 mmol reduced the H 2 O 2 yield. Research has shown that the formation of clusters in the gel step was controlled via the amount of proton amines, which further affects the porosity of the catalyst. , As shown in Figure S6, all samples displayed type IV isotherms of N 2 adsorption–desorption, suggesting the coexistence of mesoporous, macroporous, and microporous structures. The specific surface area and pore volume of PCMs decreased in the order of 2.68 mmol < 0.68 mmol < 0 mmol, indicating that DDA can reduce network clusters and porosity (Table S4).…”

Hybrid Proton-Exchange Membrane Based on Perfluorosulfonated Polymers and Resorcinol–Formaldehyde Hydrogel

“…The perfluorosulfonated membrane spectra analysis shows a typical fingerprint as reported in literature [ 43 , 44 , 45 ]: 551 cm −1 associated with torsion and bending vibrations t (CF 2 ); 626–653 cm −1 associated with rotation vibrations (CF 2 ); 717 cm −1 associated with symmetry vibrations (CF2); 805 cm −1 associated with (C–S) vibrations; 963–980 cm −1 associated with (C–O–C) vibrations; 1059 cm −1 associated with symmetry vibrations (SO3-); 1127 cm −1 associated with asymmetry vibrations (SO3-); 1150–1243 cm −1 associated with asymmetry vibrations (CF2); 1300–1319 cm −1 associated with (C–C) vibrations; and 1471 cm- 1 associated with asymmetry vibrations of (SO3H). In PFSA–RF spectra, an RF-resin-specific response could be identified: 1646 and 1490 cm −1 associated with C=C aromatic benzene ring stretching and scissor vibrations, respectively; 1380, 1311, and 1297 cm −1 associated with O–H in-plane bending; 1167 and 1152 cm −1 associated with C–O symmetric and asymmetric stretching, respectively; 1077 cm −1 associated with the C–O–C linkage stretching vibrations of methylene ether bridges between two resorcinol molecules; and 773,740 cm −1 associated with C–H aromatic group stretching and out of plane bending [ 46 , 47 , 48 , 49 ].…”