Papers by Keyword: Polypyrrole

Abstract: This investigation focused on the photocatalytic degradation of o2-chlorophenol in aqueous solution by using hexagonal boron nitride (h-BN) doped polypyrrole (PPy) composite under solar irradiation. The composite was prepared via in-situ oxidation polymerization method using FeCl3 as oxidation agent. The synthesized h-BN/PPy composite were comprehensively characterized using x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The photodegradation of 2-chlorophenol was performed under direct sunlight for 180 minutes with initial concentration (50-250 mg/L) and pH (3-9). h-BN/PPy composite efficiently degraded 2-chlorophenol (91.1%) with optimum conditions at pH 6 and 50 mg/L initial concentration compared to PPy and h-BN.

Abstract: Polyurethane (TPU)/polypyrrole (PPy) blends were successfully prepared by the solution blending process with different contents of reduce graphene oxide (rGO). The controlled synthesis of PPy/rGO composites was reported by varying graphene contents of 10, 20, 30 and 40% w/v. Fourier transform infrared (FTIR) and Scanning electron microscope (SEM) were used to characterize their structures and morphologies. The SEM images show the growing of PPy along the surface of graphene. FTIR illustrated that the PPy/rGO composites were in the doped state. The electrical conductivity of PPy/rGO composites with the concentration of graphene at 40% was about 30 times higher than that of pure PPy. Thermogravimetric analyzer (TGA) thermograms indicated that the PPy/rGO composites have better thermal stability than pure PPy.

Abstract: Polyacrylamide/polypyrrole (PAM/PPy) hydrogel was developed for the application in controlled drug delivery. PAM/PPy hydrogel was synthesized via free-radical polymerization of acrylamide using ammonium persulfate (APS) as initiator in the dispersion of PPy nanoparticle. N,N’-methylenebisacrylamide (MBA) and N,N,N’,N’-tetra-methylenediamine (TEMED) were utilized as cross-linker and accelerator, respectively. Salicylic acid (SA) was selected as a model drug in this work. The effect of PPy contents on SA-loading and releasing performances was investigated. The more PPy content was incorporated, the greater SA-loading and releasing were found. This is attributed to the increasing pore size of the PAM hydrogel when PPy nanoparticles were incorporated. Drug releasing performance from the SA-loaded PAM/PPy hydrogel were controllable under the applied potential of 1.0 volt. The research exhibits the potential of using conductive polymer hydrogel to control the drug release rate at an optimal desired level.

Abstract: The prepared Polypyrrole/Alumina-Iron oxide nanocomposite has showed 100% adsorption capacity in removing Copper ions from synthetic waste water. The nanocomposite was analyzed using SEM, TEM, FTIR, XRD and EDX. Batch mode adsorption studies were done to check the feasibility of prepared nanomaterial. Adsorption efficiency of the nanocomposite was measured using UV visible atomic absorption spectrophotometry and found 100 % at pH 8. Influence of inceptive Copper concentration, adsorbent dosage, time of contact, temperature, time with dosage, time and concentration were also tested to determine the optimum value in the uptake of Copper ions. Langmuir and Freundlich adsorption isotherm studies were analysed to understand the process of heavy metals adsorption and found best fitted to Freundlich Isotherm.

Abstract: Study on pyrrole electropolymerization is the preliminary step in synthesizing polypyrrole membranes, which can be used for various purposes in biosensor. In this work, electropolymerization process and electrochemical analysis of polypyrrole as an electroactive polymer have been studied by cyclic voltammetry. Pyrrole was electropolymerized to form polypyrrole in an aqueous potassium chloride solution at different pHs using phosphate buffer. The results showed that a potential range of 0-1200 mV is suitable for polypyrrole electropolymerization using the Ag|AgCl electrode as the reference. The formation of polypyrrole is stable at a scan rate of 100 mV/s. In addition, the optimized pyrrole electropolymerization was obtained using 0.1 M pyrrole and phosphate buffer at pH of 2-6. Taken together, this study can be used as a reference for the synthesis of other conducting polymers.

Abstract: Polypyrrole (PPy) is an attractive scaffold material for tissue engineering with its non-toxic and electrically conductive properties. There has not been enough information about PPy usage in skin tissue engineering. The aim of this study is to investigate biocompatibility of polyacrilonitrile (PAN)/PPy nanofibrous scaffold for human keratinocytes. PAN/PPy bicomponent nanofibers were prepared by electrospinning, in various PPy concentrations and with carbon nanotube (CNT) incorporation. The average diameter of electrospun nanofibers decreased with increasing PPy concentration. Further, agglomerated CNTs caused beads and disordered parts on the surface of nanofibers. Biocompatibility of these PAN/PPy and PAN/PPy/CNT scaffolds were analyzed in vitro. Both scaffolds provided adhesion and proliferation of keratinocytes. Nanofiber diameter did not significantly influence the morphology of cells. However, with increasing number of cells, cells stayed among nanofibers and this affected their shape and size. In this study, we demonstrated that PAN/PPy and PAN/PPy/CNT scaffolds enabled the growth of keratinocytes, showing their biocompatibility.

Abstract: Pyrrole was successfully polymerized on copper surface in ethanol solution using hydrogen peroxide as catalyst to generate an adherent and homogeneous polypyrrole (PPy) coating. The PPy was formed of clusters composed of small spherical grains. The layer has remained stable when immersed in 0.1mol L^-1 NaCl for 7 days, which indicated that the copper-PPy arrangement is stable in corrosive environment. The polarisation curves showed that the PPy layer can promote a positive displacement in the corrosion potential compared to the value of the uncoated copper. It also was observed that the corrosion current density decreases sharply in the presence of the lauric acid as dopant. These results indicate that PPy-lauric acid can act as a protective layer on copper and improve the overall corrosion performance.

Abstract: Polypropylene/three-carbon-filler composite bipolar plates (BPs) of direct methanol fuel cell (DMFC) were fabricated by an injection molding. The composite materials were made of polypropylene (PP), carbon black, carbon fiber and graphite. Gas flow channel surfaces on the BPs were subsequently modified by polypyrrole (PPy) using a coating technique in order to improve surface electrical conductivity. This research is a feasibility study to use PPy-coated PP composite as BPs in a DMFC. The surface electrical resistance and performance in a fuel cell containing the composite BPs under DMFC operating conditions were evaluated against conventional graphite BPs. The surface resistance values of PPy-coated PP composites decreased around six orders of magnitude, compared with those values of PP composites. According to the performance results, PPy-coated composite BPs can be used in DMFC if the surface adhesion between a PPy layer and the BP surface was further improved.

Abstract: Immobilise enzymes can offer many advantages over their soluble forms making this is a topic of active research in enzyme technology for industrial applications. There are various methods for enzyme immobilization as well as support materials. The methods and supports used for immobilisation of certain enzyme are chosen to ensure the highest retention of activity and its stability. Enzyme Horseradish peroxidise (HRP) was used extensively in molecular biology applications primarily for its ability to amplify a weak signal and increase the detectability of a target molecules. Recently class of conducting polymers are used as a polymeric support. Among the family a conducting polymer, polypyrrole (PPY) has intensively been used for various reason because of its unique properties such as ease of synthesis by chemical or electrochemical oxidative polymerization of the monomers, role as a polymeric support and also have potential in various field . It has alternating single and double carbon-carbon bonds along the polymeric chains. The highly conjugated polymer chain can be assigned reversible chemical, electrochemical and physical properties controlled by a doping/ de-doping process, which makes this polymers very attractive as transducer materials in various sensing devices. This paper reports the process of immobilised enzymes on polymeric substrate and the role of enzymes in PPY conductivity. The characterization was done using UV-Visible, FTIR and four point probe.

Abstract: The polypyrrole-coated cotton fabrics were prepared via in situ chemical oxidative polymerization. The polymerization time of 120 min and reaction temperature of 25 °C were employed in this study. The major factors on electricities of the fabrics, including types of oxidants and molar ratio of pyrrole monomer to oxidant, were studied. Ferric trichloride hexahydrate (FeCl₃·6H₂O), ammonium persulfate ((NH₄)₂S₂O₈) and sodium periodate (NaIO₄) were selected to carry out the synthesis of polypyrrole. When FeCl₃·6H₂O acted as oxidant, the optimum conductivity of 4×10^-3 S·cm^-1 could be obtained by changing molar ratio of Py to FeCl₃·6H₂O. By contrast, the highest conductivity of fabrics which used (NH₄)₂S₂O₈ as oxidant was 1.8 ×10^-4 S·cm^-1. The evolution of resistivities, morphology, surface chemistry and mechanical strength were characterized by a four-points probe resistivity system, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and mechanical test instrument.