Papers by Keyword: Sulfonation

Abstract: This research reported on the preparation of proton exchange membranes from electronic and food packaging waste composed of Styrofoam. Polymeric Solution of 25 wt. % Styrofoam dissolved in an acidic mixture (DMF: THF at 70:30 volumetric ratio) were prepared. Polymeric membranes were fabricated by electrospinning. The effect of MgO NPs addition to polymeric solution was studied. Before sulfonation reaction, SEM results showed a clear reduction in average fiber diameters from (1.5-2) µm to (0.5-1) µm after addition of 0.04 wt.% MgO NPs. After sulfonation reaction by 35% diluted sulfuric acid, SEM results show an increase in average fiber diameters from (0.5-1) µm to (2-2.5) µm. This increase may be correlated to hydrophilic behavior results from incorporation of (-SO₃H) to aromatic ring. FTIR analysis indicates the presence of new peaks related to sulfonic acid group (SO₃H) attachment to polymeric chain. Proton conductivity as well as water uptake in membranes increased with increasing MgO NPs percentage.

Abstract: This study reports the synthesis of cellulose nanocrystals (CNC) sulfonation from the isolated cellulose nanofibers (CNF) of the Eichhornia crassipes stems. The crystallization of fibers was done by varying the time of sulfonation, 30 min (CNC30) and 60 min (CNC60), in 6M sulfuric acid. Scanning electron microscope images (SEM), and energy dispersive X-ray spectroscopy (EDS) revealed that the crystals have a grain flakey-like structure with the detected presence of oxygen, carbon, and sulfur (due to the sulfonation) atoms. Using Fourier transform infrared spectroscopy (FTIR), unique functional groups of CNCs were detected. Further, the X-ray diffraction (XRD) scans revealed that CNCs have a cellulose-Ib monoclinic unit cell structure with Miller indices (200) and (400). Additionally, results showed that CNC30 has 74.45% and CNC60 has 76.13% crystal index percent and a crystal thickness of 0.048 nm for CNC30 and 0.047 nm for CNC60. Lastly, d-spacing of CNC30 and CNC60 exhibited values of 3.26 Å and 3.20 Å, respectively. These results warrant further studies on future applications of the produced CNC from Eichhornia crassipes fibers.

Abstract: Out of the perovskite material used in Perovskite Solar Cells, methylammonium lead triiodide (MAPbI₃) is the most studied, proving to yield a device with high power conversion efficiency. However, this perovskite material has a high tendency to degrade, especially when exposed to high humidity and ambient atmosphere. The degradation issue has led to its poor morphology, which eventually affects the device's power conversion efficiency based on this perovskite material. Therefore, this study aims to enhance the morphological property of the perovskite thin film by incorporating sulfonated reduced graphene oxide (srGO) as a dopant. The reduced graphene oxide is synthesized through modified Hummer's method and further sulfonated before being incorporated into the perovskite thin film deposited under relative humidity above 80% in ambient conditions. The srGO has successfully assisted the nucleation growth of MAPbI₃ with the increment of grain size is approaching micron-sized. In this work, the optimized weight percentage of srGO in methylammonium iodide (MAI) precursor is found to be 20% resulting in grain size in the diameter range of 300 to 1000 nm. Hence, this perovskite doped srGO would be incorporated as the active layer for further application, especially in inverted planar perovskite solar cells.

Abstract: Nowadays the development of biodiesel production as an alternative renewable energy became crucial. The reusability of enzymes as biocatalysts in biodiesel production has limitations and can be improved by the immobilization process onto the appropriate solid support, such as polyethersulfone (PES). Polyethersulfone has been synthesized utilizing microwave-assisted reaction method (400 W, 170 °C, 60 minutes). Nitration reaction of PES was performed by refluxing the synthesized PES with the mixtures of H₂SO₄ (0 °C, ± 30 minutes) and HNO₃ (25 °C, 4 hours). The –NO₂ groups of the synthesized PES-NO₂ was subsequently reduced to be PES-NH₂ using SnCl₂.2H₂O as reducing agent by reflux method (60 °C, ± 3 hours). The structure of PES and its derivatives was confirmed by FTIR and ¹H-NMR. Candida antarctica lipase was successfully immobilized onto the synthesized PES and its derivatives, which were confirmed by its FTIR spectra and its activity tests of the supernatants in hydrolyzing p-nitrophenol palmitate (pNPP) into p-nitrophenol (pNP). The results showed that the conversion percentage of pNPP to become pNP were 20.6% (free enzyme), 18.9% (PES-enzyme), and 3.7% (PES-NH₂-enzyme). The decrease in the supernatant enzyme activity showed that the enzyme has been successfully immobilized through physical adsorption onto the synthesized polymers.

Abstract: Sulfonated graphene oxide (sGO) was used as a filler to enhance performance of sulfonated poly(ether ether ketone)(sPEEK) membrane. The sGO was firstly prepared by treating graphene oxides (GO) with sulfanilic acid at 70 °C for 20 h. The sGO was characterized by FTIR and XPS techniques. Composite membranes of various amount of sGO were fabricated via solution casting method. The properties of composite membranes were investigated by measuring ion exchange capacity (IEC), water uptake, ion conductivity and vanadium ion permeability. From the results, it was found that the IEC and water uptake of the membranes increased after adding the sGO. Ion conductivity of the sPEEK membrane also increased from 8.94*10^-3 Scm^-1 to 10.55*10^-3 Scm^-1. Moreover, permeability of vanadyl sulfate (VOSO₄) through the composite membranes were decreased. These composite membranes exhibit great potential for vanadium redox flow batteries application.

Abstract: Polystyrene sulfonate (PSS) were prepared by sulfonation method of polystyrene using sulfuric acid. Abundant amount of polystyrene waste can be reused as a coagulant, membrane for polymer fuel cell and anionic-cationic polymer interactions. The characterization of PSS was carried out by using UV-Vis, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectra, molecular weight and analysis of sulfonation degree. The degree of sulfonation was obtained at 94,18%. Ionic interaction between anionic polymer PSS and cetyltrimethylammonium bromide (CTAB) as cationic compound in aqueous solution were analyzed by using dynamic light scattering (DLS), conductometry and fluorimetry. Behavior of conductivity have been calculated the critical micelle concentration (cmc). The FTIR and ¹H-NMR spectra showed the ionic interaction between PSS and CTAB. This ionic interaction can be controlled by changing the polymer concentration.

Abstract: Styrene-Butadiene Rubber (SBR) composites incorporated with different fillers with similar filling ratio, were fabricated by latex compounding method. The particle size, tensile strength, abrasion resistance of the vulcanized rubber composites were investigated. The sulfonated bamboo charcoal-chitosan hybrid (sBC-CS) showed great dispersion rate and smaller particle size compared with those of other fillers. In addition, this composite exhibited the best mechanical reinforcing performance among the four fillers.

Abstract: Sulfonated Polybenzoxazoles (sPBO) with sulfonation degree ranging from 10% to 30% were synthesized from 4,6-diaminoresorcinol dihydrochloride (DAR), terephthalic acid (TPA), 5-sulfoisophthalic acid monosodium salt (SIPA) by direct polycondensation in polyphosphoric acid (PPA). The structures of sPBOs were verified by FTIR and elemental analysis. The values of inherent viscosity ranged from 2.56 to 1.12 dL/g and decreased with the increasing of sulfonation degree. TGA analysis showed sPBOs were thermal stable up to nearly 250°C. sPBO/PPA polymerization solution were hot pressed directly to form PPA doped sPBO membranes since sPBO was insouble in common solvents. The PPA doping level was about 340%(wt) per gram of sPBOs by theoretical calculations. The tensile strength of PPA doped sPBOs membrances ranged from 9.1 to 3.2 Mpa. At high temperature, sPBO membranes showed excellent proton conductivity. For instance, sPBO membrane with a sulfonation degree of 10% exhibited a proton conductivity of 0.123 S/cm at 170°C.The experimental results indicated sPBO are promising for proton exchange membranes for high temperature proton exchange membranes.

Abstract: Cotton and sulfuric acid that concentration is 98% as the raw material, to compare the resulting solid carbon sulfonic acid content of the material under different reaction temperatures. FTIR analysis shows that the cotton carbon is an amorphous carbon after sulfonation reactions, a sulfonic acid group present in the resulting material. When the sulfonation temperature is 170 °C, the prepared cotton carbon sulfonic acid has the highest acid content. By the sulfuric acid TG/DTG curve analysis, it verify: 170 °C is the highest activity temperature point of sulfuric acid sulfonation reaction.

Abstract: Coaled carbon-based solid acid (Coal-SO₃H) was prepared by sulfonating ultra-low ash Taixi coal and characterized by XPS, IR and PXRD. It was used as a new, efficient and recyclable catalyst for fructose dehydration to form 5-hydroxymethylfurfural (5-HMF) in dimethyl sulfoxide (DMSO). Reaction time, temperature and catalyst amounts were investigated respectively. The results showed that 81.6 % yield of 5-HMF achieved in dimethyl sulfoxide (DMSO) at 140 °C after 140min using the Coal-SO₃H as catalyst. The ash, carbonization temperature and sulfonated way which could influence the catalyst performance for preparing 5-HMF had been investgated.