Papers by Keyword: Polyacrylonitrile

Abstract: Recent interests in hybrid polymers for fuel cell applications have given rise to the exploration, modification, and application of various polymer ionomers. Polymer membranes doped with suitable fillers have improved fuel cell performance compared to the pristine polymers. In this study, three ionomers, PAN, PVP, and PVA were synthesised idividually and then functionalised with zirconium phosphate nanoparticles as membrane nanofillers. The nanofibers were synthesised using the sol-gel polymerisation method from their respective precursors dissolved in either water or DMF solution. This was followed by their subsequent fabrication through the incorporation of the zirconium phosphate nanoparticles, which were synthesised from their precursor salt using the precipitation method. Techniques such as SEM, FTIR, TGA, and XRD were employed to characterise the physiochemical properties of the synthesised polymers. In addition, the electrochemical properties of the synthesised polymers were evaluated using CV and EIS. The obtained results showed that conductive nanofibers were successfully synthesized. As the scan rates increased under cyclic voltammetry, the reduction peak for PVP voltammograms disappeared, and the PAN exhibited an irreversible redox system. It is also noticeable that when scan speeds increase, the oxidation peaks for PAN voltammograms shift to higher potentials. On the other hand, the TGA results indicated that these nanoparticles had excellent thermal stabilities, making them suitable for use in fuel cell membranes under tough conditions. Based on these findings, PAN, PVA, and PVP polymer materials can be used as filler (dopant) materials for fuel cell membranes.

Abstract: This work reported the successful fabrication of a low-cost electrospun PAN nanofiber coated with Cu₂O QDs. Our works reveal that the spray coating method was effective in applying a homogenous distribution of Cu₂O QDs on the surface of PAN nanofiber. The as-synthesized Cu₂O QDs have an absorption edge at 510 nm and band gap energy of 2.5 eV indicating a light-sensitive photocatalyst. The SEM image showed an even distribution of Cu₂O QDs on the top of PAN nanofibers with an average diameter of 454.45 ± 124.732 nm. The wettability of the as-made nanofibers was determined using the contact angle method. Our PAN/Cu₂O QDs nanofibers showed hydrophilic behavior. The reactive oxygen species generation study also indicated the ability of our PAN/Cu₂O to generate singlet oxygen. Our results indicate the promising potential of PAN/Cu₂O as wound healing fabric due to the advantageous natural properties of copper and hydrophilic fabric.

Abstract: Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted attention for energy storage systems because of their high specific capacity, low cost, and safety. However, practical application of the zinc anode in mild acidic electrolytes is limited by several issues such as dendrite formation, corrosion, hydrogen evolution reaction, passivation and relatively low cycling performance. Coating the zinc anode with graphite (GP) can partially solve these issues and improves the cycling performance of ZIB. However, after long-term charge/discharge cycles, zinc tends to migrate and redeposit over the surface of GP owing to the electronic conductivity of GP particles. Thus, after long-term cycling, the issues mentioned are back. Fabrication of artificial solid electrolyte interphase (ASEI) on the surface of the zinc anode shows high potential for solving these issues. In this work, polyacrylonitrile (PAN) with zinc trifluoromethanesulfonate (Zn(CF₃SO₃)₂) (PANZ) as ASEI was coated on the GP layer onto the zinc anode (PANZ@GP@Zn), and compared with the anode having GP coated layers and pristine zinc anode. The coating layer was prepared by the doctor blading method. The result showed that the PANZ@GP@Zn anode can reduce zinc deposition over the anode surface when compared with the GP@Zn anode, leading to the high cycling stability of ZIBs and extending the battery's life.

Abstract: Water contamination by heavy metals is one of the most serious environmental problems and harms human life. Numerous nanotechnologies have been utilized to overcome this problem so far. Herein, we introduce lignin/polyacrylonitrile (PAN) composite nanofibers prepared via electrospinning for the removal of lead from aqueous solution. The effects of blend ratios between lignin and PAN concentration (LP) were investigated. The performance of adsorption process depends on the following parameters including contact time of adsorbent and adsorbate (equilibrium times: after 16 h. for 10 mg/L of lead concentration), types of nanofibers (LP55 at 1 g/L), and the percentage of lead removal was 72.5 % within 24 hours by LP55 nanofibers. The highest correlation coefficients were performed for the pseudo-second order kinetic model both LP55 and PAN nanofibers. This study demonstrates that the potential of the biomass-derived material with nanotechnology for environmental remediation.

Abstract: The need for the development of renewable energy harvesting and storage devices is on the front as the world is facing an environmental crisis due to the consumption of gallons of fossil fuels. One of the promising solutions on which many researchers are concentrating is supercapacitor as it possesses high energy and power density. Current literature study focusing on developments already had in the field of manufacturing of supercapacitors using different precursors, testing conditions, fiber dimensions, and their performance analysis. Most of the studies found that Polyacrylonitrile (PAN) based electrospun carbon fiber webs is a potential electrode material for supercapacitors. The information gathered in this article is about the electrospinning technique, Surface and electrochemical characterization methods, and recent advances in their performance are highlighted. Also, enhancement in electrochemical performance through optimization of electrospinning parameter, a precursor modification by the addition of active materials (such as carbon nanotubes, metal oxides, and catalysts), heat and surface treatment followed, and optimum fibrous structures are summarized.

Abstract: Electrospinning is one method to produce nanosized materials in a form of fibers with a large variety of polymeric solutions. In this research, Polyacrylonitrile (PAN) dissolved in N,N-Dimethylformamide (DMF) as the primary solvent, loaded with keratin protein solution, was blended using the said fabrication method to change its properties. The loading of the keratin solution concentrates varied from 5%, 7%, and 10% relative to the volume of the solution. The PAN-keratinnano substances were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Cyclic Voltammetry (CV), and Galvanostatic Cycling with Potential Limitation (GCPL) to illustrate the properties of the fiber. The SEM micrographs showed that upon adding keratin into the PAN the diameter lengths of the imaged fibers were still nanofiber. As the viscosity of the solution is increased, the beads become bigger, the average distance between beads and the fiber diameter increases, and the shape of the beadings changes from spherical to spindle-like. In addition, CV and GCPL revealed that as the potential scan rate is being increased, the surrounded area of the CV also increases. The presence of redox peaks implies that a faradaic process occurs. The migration and diffusion of ions can be supported by the carbonized fibers. GCPL shows the triangular shape with symmetric charging and discharging slopes at a current density of 0.5mah, 1mah, 1.5mah and 2.5mah, confirming that the electrodes behave as a pure electric double layer capacitor (EDLC).

Abstract: Chicken feathers are known for its unique properties such as low density, warmth retention, and distinct morphological structure [1]. Despite these unique properties, chicken feathers are considered a waste byproduct of the poultry industry [2]. To utilize feather waste, it was used as an additive to reinforce Polyacrylonitrile (PAN) polymer in the form of Keratin Extract. The highlight of the study is to prepare and characterize PAN with chicken feather keratin as additive by electrospinning. Keratin was extracted under reduction method with the use of sodium sulphide and solubilized with NaOH [3]. The presence of Keratin was confirmed with Fourier Transform Infrared Microscopy (FTIR) and Ultraviolet–visible Spectroscopy (UV-Vis).PAN nanofibers with different keratin loadings were formed by electrospinning process and Dimethylformamide (DMF) as solvent. The electrospun nanocomposite membranes were analyzed using Scanning Electron Microscopy (SEM), FTIR, contact angle goniometer, and Ion-Adsorption test. Addition of keratin into the polymer solution, decreased the average fiber diameter from 91nm (Pure Keratin), 84nm (PAN/1%Keratin), 71nm (PAN/3%Keratin) to aggregates (PAN/5%Keratin). Also, the change in morphology affected the polymer’s hydrophilicity. As the percentage loading of keratin increases, the average contact angle decreases. The average contact angle of Pure Pan, 1%, 3%, and 5% keratin decreased from 28.21°, 18.85°, 16,76° to 15.34°. The effect of the fiber on conductivity was also tested with a salt bath method. 3M of NaCl solution presented a conductivity of 93.0 mS. Upon the addition of Pure PAN in saltwater Solution, the conductivity had decreased to 60.0mS which indicated that some ions from the NaCl had adhered to the membrane. Upon the addition of Keratin nanofibers, it can be observed that the conductivity increases to 61.0 mS, 96.8 mS. and 100.1 mS as the percentage of keratin loading increases.

Abstract: Heavy metal adsorption (HMA) is one of the remediation techniques used to remove heavy metals from water/wastewater. Composite membranes with functionalized additives for selective adsorption are being investigated. In this study, Carbon Quantum Dots – Polyacrylonitrile/Polycaprolactone nanocomposite membranes are synthesized by electrospinning which is intended for HMA of Cu²⁺. The nanofiber mats were characterized using SEM, FTIR, and Contact Angle. Batch adsorption process were performed and to utilize the AAS for kinetic adsorption behavior analysis. SEM micrographs revealed the addition of CQD in PAN and PAN/PCL membrane matrix shifted the fiber size distribution from 50 – 100 nm to 150 – 250 nm indicates the decrease in effective surface area. FTIR analysis exhibited vibrational peaks and binding of distinct functional groups such as amine, nitrile, carboxylic, hydroxyl, and carbonyl for CQD, PAN and PCL, respectively. CQD in aqueous form further increases the hydrophilicity of PAN/PCL membrane matrix which is essential for HMA of Cu²⁺ ions. The increase of nanofiber mat’s adsorption capacity with respect to contact time obtained a maximum at 63.45 mg/g with a maximum efficiency of adsorption at 90.74%. Kinetic adsorption studies show that the pseudo – first order kinetic model best fits the data for CQD – PAN/PCL nanofiber mat in Cu²⁺ ions obtaining a correlation value of R² = 0.9418 and a rate constant k = 0.0172 min¹ indicating the adsorption behavior follows the physical adsorption process involving Van der Waals forces and hydrogen bonding between the adsorbent and adsorbate.

Abstract: PAN membranes were prepared from mixture of good and weak solvents by two different methods. Immersion precipitation method with and without volatile component evaporation used for membrane preparation. From analysis of Hansen solubility parameters DMSO chosen as good solvent and acetone chosen as weak solvent. The effect of volatile weak solvent investigated on pore size and filtration performance. By evaporation of acetone, it was possible to increase polymer concentration on casting solution and obtain smaller pore size in comparison to membrane prepared from DMSO. Membranes prepared from DMSO/acetone without solvent evaporation had even lower pore size and higher filtration performances. It was shown, that presence of acetone creates more pronounced effect on pore size than increase of polymer concentration. As a result membranes with pore size 3.7 nm obtained from Acetone/DMSO mixture with composition 50:50 and polymer concentration 50 % by immersion precipitation Resulted membranes have permeance 23 kg/m²·h·bar and retention of Lysozime 99 %.

Abstract: Thermal treatment of polyacrylonitrile (PAN) with different molecular weights pre-irradiated by electron beam was prepared to study the radiation effects on thermal behaviors. Thermal properties were characterized by thermogravimetric analyses. Char yields (800 oC) of PAN samples are increased remarkably with the increase of irradiation dose, and all samples can obtain the similar high char yields (~57 %) at the dose of 300 kGy. FTIR and UV-visible absorption spectra of pre-irradiation PAN illustrate the formation of –HC=N-N=CH-crosslinking conjugation across the polymeric chains, which can improve PAN’s thermal behaviors. Char yields of pre-irradiated PAN samples are mainly dominated by their gel contents, and they are almost independent of the molecular weights of PAN samples.