Electrically conductive composites of polyurethane derived from castor oil with polypyrrole‐coated peach palm fibers

Electrically conducting fibers were prepared through in situ oxidative polymerization of pyrrole (Py) in the presence of peach palm fibers (PPF) using iron (III) chloride hexahydrate (FeCl₃·6H₂O) as oxidant. The polypyrrole (PPy) coated PPF displayed a PPy layer on the fibers surface, which was responsible for an electrical conductivity of (2.2 ± 0.3) × 10⁻¹ S cm⁻¹, similar to the neat PPy. Electrically conductive composites were prepared by dispersing various amounts of PPy‐coated PPF in a polyurethane matrix derived from castor oil. The polyurethane/PPy‐coated PPF composites (PU/PPF–PPy) exhibited an electrical conductivity higher than PU/PPy blends with similar filler content. This behavior is attributed to the higher aspect ratio of PPF–PPy when compared with PPy particles, inducing a denser conductive network formation in the PU matrix. Electromagnetic interference shielding effectiveness (EMI SE) value in the X‐band (8.2–12.4 GHz) found for PU/PPF–PPy composites containing 25 wt% of PPF–PPy were in the range −12 dB, which corresponds to 93.2% of attenuation, indicating that these composites are promising candidates for EMI shielding applications. POLYM. COMPOS., 38:2146–2155, 2017. © 2015 Society of Plastics Engineers     

Investigations on the adhesion and interfacial properties of polyurethane foam/thermoplastic materials

The adhesion and interfacial properties of polyurethane (PU) foams with thermoplastic (TP) materials were investigated using different techniques. The adhesion performance of PU foam with TP materials was evaluated using the peel test method, and the adhesion durability was checked after different climate treatments. X‐ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and contact angle measurements were used to study the surface and interface morphology of PU foam and TP material system. Three types of PU foam samples which differ in their composition and also five commercially available TP blends systems, based on poly(carbonate), poly(styrene‐co‐maleic anhydride), poly(acrylonitrile‐butadiene‐styrene), and silicone acrylate rubber have been used. The slow reacting foam shows the best adhesion properties with all the TP materials. The climate treatments strongly effected the PU foam adhesion durability with poly(carbonate) containing TP materials (70–80% loss in adhesion), but nearly no effect with poly(styrene‐co‐maleic anhydride). The samples with lowered adhesion could be separated by peeling without visible foam residues on the TP surface. AFM, XPS, and surface tension studies have shown that the surface properties of the TP material are still governed by the PU foam. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 479–488, 2007     

Preparation of graphite oxide/polyurethane foam material and its removal application of malachite green from aqueous solution

Synthetic dyes are commonly used in textile, paper, leather, food, plastic and cosmetic industries. In this study, a series of novel graphite oxide/polyurethane (GO/PU) polymeric foam materials were prepared by foaming technique. The GO/PU was applied to remove malachite green (MG) from aqueous solution. When static adsorption experiment was carried out with a GO content of 3.0%, a GO/PU dosage of 40 mg/mL, a temperature of 50°C, and a time of 3 h, the highest adsorption efficiency can reach 99.7%. The kinetics, equilibrium and thermodynamics of MG adsorption onto GO/PU polymeric foam material were investigated. The results indicated that adsorption behavior was found to follow closely the pseudo‐second order kinetics, equilibrium data were well fitted by Langmuir adsorption model and the adsorption process was spontaneous and endothermic. Prepared GO/PU foam material has potential application for the wastewater treatment containing MG dye. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40988.     

Synthesis of copolymer of aniline and pyrrole by inverted emulsion polymerization method for supercapacitor

Copolymer of aniline and pyrrole was synthesized by inverted emulsion polymerization method by oxidizing aniline and pyrrole using benzoyl peroxide in presence of sodium laurylsulphate surfactant and p‐toluenesulphonic acid. Copolymer samples were characterized by infrared, X‐ray diffraction and scanning electron microscopic techniques and compared their properties with the corresponding homopolymers. The optimum reaction conditions for the preparation of copolymer with reasonably good yield (1.72 g) and conductivity (7.3 × 10^?2 S/cm) were established. The synthesis procedure was extended to prepare copolymer samples using various protonic acids. Electrochemical characterization such as cyclic voltammetry, charge‐discharge and impedance were carried out on symmetrical supercapacitor cell consists of poly(aniline‐co‐pyrrole)‐p‐toluenesulfonic acid salt, wherein, the copolymer salt was synthesized using equal amount of aniline and pyrrole monomers. The values of specific capacitance, energy and power densities for poly(aniline‐co‐pyrrole)‐p‐toluenesulfonic acid system (PANI‐PPy) were calculated from charge‐discharge studies and are found to be 21 F/g, 5.7 Wh/Kg and 100 W/Kg respectively. Impedance analysis showed specific capacitance value (57 F/g) at 0.01 Hz at 0.22 V. Among the copolymer salts, copolymer prepared with sulfuric acid showed higher capacitance (66 F/g). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Enhanced microwave absorbing properties of lightweight films based on polyaniline/aliphatic polyurethane composites in X band

Polymer blends based on nanostructured polyaniline (PANI) doped with hydrochloric acid (HCl) and para‐toluene sulfonic acid (PTSA) introduced into aliphatic polyurethane matrix (PU) are synthesized to produce flexible thin composite films for microwave absorbers. The effects of dopant type, PANI content and film thickness on morphologies, dielectric and microwave absorption properties in the X‐band are studied. It reveals that real and imaginary parts of the complex permittivity are proportional to filler concentrations and type of doped PANI. The PANI‐PTSA/PU films show higher permittivity and better microwave absorbing properties than PANI‐HCl/PU for the same weight fraction of PANI. The minimum reflection loss RL_(dB) values for the PANI‐PTSA/PU are ?37 dB at (20% PANI and 11.6 GHz) and ?30 dB at (15% PANI and 11.3 GHz) for thicknesses of 1.2 and 1.6 mm, respectively. These high values of reflection losses make the obtained lightweight and flexible composites promising radar absorbing materials (RAM). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40961.     

Novel floating photocatalysts based on polyurethane composite foams modified with silver/titanium dioxide/graphene ternary nanoparticles for the visible‐light‐mediated remediation of diesel‐polluted surface water

Photocatalyst loading on a floating substitute is accepted as a promising method for the remediation of diesel‐polluted surface water. Therefore, novel photocatalysts based on polyurethane foams modified with silver/titanium dioxide/graphene ternary nanoparticles (PU–Ag/P25/G) were synthesized and investigated. Scanning electron microscopy, energy‐dispersive X‐ray spectrometry, X‐ray diffraction, Fourier transform infrared spectroscopy, and UV–visible spectroscopy showed the coexistence of Ag, Degussa P25 (P25), and graphene and the nanoscale dispersion of nanoparticles in the matrix and on the surface of the polyurethane (PU) foam. The diesel adsorption capacity of the photocatalyst reached 96 g/g. The maximum diesel degradation was found to be 76% in a period of 16 h. Compared with polyurethane‐foam‐supported P25/graphene (PU–P25/G) and polyurethane‐foam‐supported P25 (PU–P25), all of the adsorption isotherm and degradation kinetics followed the order PU–Ag/P25/G > PU–P25/G > PU–P25 > PU; this was due to the loading of different nanoparticles. Moreover, the degradation efficiency was reduced only 5% after five consecutive reactions; this showed good stability and reusability of the photocatalyst for surface water restoration. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43400.     

Conducting polypyrrole‐coated banana fiber composites: Preparation and characterization

In this study, conducting banana fibers (BF) were obtained through in situ oxidative polymerization of pyrrole (Py) on the BF surface using ferric chloride hexahydratate (FeCl₃·6H₂O) as an oxidant. Suitable reaction conditions are outlined for the polymerization of Py: oxidant/monomer molar ratio, Py concentration and polymerization time of 2/1, 0.05 mol.L⁻¹ and 30 min, respectively. Under these conditions, high‐quality conducting fibers containing polyPy and BF (PPy‐BF) were obtained with an electrical resistivity as low as 0.54 Ω.cm. The PPy‐BF was blended with different concentrations of polyurethane (PU) by mixing the two components in a vacuum chamber and then applying compression molding. The electrical resistivity of composites with 25 wt% of PPy‐BF was around 1.8 × 10⁵ Ωcm, which is approximately 10⁸ times lower than that found for pure PU. Moreover, PU/PPy‐BF composites exhibited higher mechanical properties than pure PU and PU/PPy, indicating that these conducting fibers can also be used as reinforcement for polymer matrices. The properties of the PPy‐BF obtained by the method described herein open interesting possibilities for novel applications of electrically conducting fibers, from smart sensors to new conducting fillers that can be incorporated into several polymer matrixes to develop conducting polymer composites with good mechanical properties.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

腈纶废水生化处理脱氮影响因素研究

针对聚氨酯泡沫微生物固定化载体的序批式生物膜反应器(SBBR),通过平行对比实验,考察生物脱氮过程中DO、碱度、温度、C/N等因素对实际腈纶废水的处理效果及影响,结果表明:在进水pH=8,DO在2~4 mg/L,投加碳酸氢钠0.4 g/L,温度为32℃,HRT为48 h的条件下,COD去除率可达到65%以上,氨氮去除率达99%以上。     

Comparison of COD, nitrogen and phosphorus removal between anaerobic/anoxic/aerobic and anoxic/aerobic fixed biofilm reactor using SAC (Synthetic Activated Ceramic) media

In order to remove nitrogen and phosphorus simultaneously and to develop a compact process for retrofitting a conventional activated sludge system, a new fixed-biofilm reactor was designed and tested employing an operation strategy with three and two reaction phases : anaerobic/anoxic/aerobic (Run-1) and anoxic/aerobic (Run-2). Four kinds of HRT (4, 6, 8 and 10 h) were varied to investigate the effect of nitrification and denitrification in each reactor. The results of the experiments are summarized as follows. All removal rates of COD, T-N and T-P in the water treated in Run-1 were higher than those of Run-2. The average values of COD, T-N and T-P in the treated water were reduced to 5.0 mg/L, 5.6 mg/L and 3.1 mg/L in case of Run-1. The COD and T-N removal efficiencies of Run-1 were higher than that of Run-2, but the difference between Run 1 and Run 2 was almost negligible. More than 60 % T-P removal efficiency could be achieved when the HRT was above 8 hour, but the efficiency was sharply decreased to 36% as the HRT was decreased to 4 hour in case of Run-1. Although the removal efficiency of T-P in Run-2 decreased by 56 % compared with that of Run-1, the fixed biofilm reactor using SAC media reduced the volume of reactor, and high-level COD and T-N removal from domestic wastewater was performed ; stable effluent quality was thereby achieved. The performance of Run 2 with no anaerobic reactor was mostly similar to that of Run 1 with an anaerobic reactor, except for T-P removal. Hence, according to these results, anoxic and aerobic processes using SAC media could be possible for removing organics and nutrients from municipal wastewater, in case phosphorus removal is not considered for municipal wastewater with low concentration of phosphorus.     

Simultaneous removal of Pb(II) and chemical oxygen demand from aqueous solution using immobilized microorganisms on polyurethane foam carrier

We studied the simultaneous removal of Pb(II) and chemical oxygen demand (COD) from synthetic solutions using immobilized microorganism. The immobilized microorganisms on polyurethane foam (IPUF) were successfully prepared by cultivating the microbe B350 in a mixture of culture medium and polyurethane foam (PUF). The adsorption of Pb(II) ion from aqueous solutions onto PUF and IPUF was studied by batch adsorption. IPUF exhibited high Pb(II) removal efficiency. When 0.12 g of IPUF was used to treat 50mL of 20mg/L P(II) solution at pH 7.0 and 25 °C for 120 mins, the removal ratio was 80%. The biosorption kinetics could be described by the pseudo-secondorder model, and the adsorption isotherms could be described by Langmuir and Freundlich equations. In addition, for synthetic wastewater containing Pb(II) and C₆H₁₂O₆, the removal ratios of Pb(II) and COD after being treated by IPUF for 8 hours were 92.0% and 84.2%, respectively. The removal ratio of COD clearly decreased with the increase of Pb(II) concentration, meaning that Pb(II) was toxic to the mobilized microorganisms and lower Pb(II) concentration was preferred.     

Polyurethane/poly(ethylene‐co‐ethyl acrylate) and functional carbon black‐based hybrids: Physical properties and shape memory behavior

A polyurethane (PU) was developed from poly(dimethylamine‐co‐epichlorohydrin‐co‐ethylenediamine) (PDMAE) and polyethylene glycol (PEG) as soft segment and 2,4‐toluene diisocyanate (TDI) incorporating as hard segment. Later PU was blended with poly(ethylene‐co‐ethyl acrylate) (PEEA). Poly(vinyl alcohol)‐functionalized carbon black (CB‐PVA) nanoparticles was used as filler. The structure, morphology, mechanical, crystallization, and shape memory behavior (heat and voltage) were investigated methodically. Due to physical interaction of the blend components, unique self‐assembled network morphology was observed. The interpenetrating network was responsible for 83% rise in tensile modulus and 46% increase in Young's modulus of PU/PEEA/CB‐PVA 1 hybrid compared with neat PU/PEEA bend. Electrical conductivity was increased to 0.2 Scm^?1 with 1 wt % CB‐PVA nanofiller. The original shape of sample was almost 94% recovered using heat induced shape memory effect while 97% recovery was observed in an electric field of 40 V. Electroactive shape memory results were found better than heat stimulation effect. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43481.     

Facile fabrication of polyaniline/polypyrrole copolymer nanofibers with a rough surface and their electrorheological activities

Hierarchical polyaniline/polypyrrole (PANI/PPy) copolymer nanofiber was prepared via a two‐step method and adopted as dispersing materials for electrorheological (ER) fluids. The first step was used to synthesize PANI nanofibers by a rapid mixing method. Subsequently, the PANI/PPy copolymer nanofibers with a rough surface were obtained using an in situ polymerization method continuously. The morphology of the resultant PANI/PPy copolymer nanofibers can be controlled by varying the amount of Py monomer in the secondary in situ polymerization method. The rough surface of PANI/PPy copolymer nanofibers were confirmed by scanning electron microscopy and transmission electron microscopy. The diameter of PANI/PPy nanofiber is within the range 100–200 nm. The obtained PANI/PPy copolymer particles all exhibit amorphous structure through X‐ray diffraction measurement. We also demonstrated that the hierarchical PANI/PPy copolymer nanofibers exhibited characteristic ER behaviors, which were investigated using a Haake rotational rheometer at various electric field strengths. The ER efficiency e for PANI‐1mLPPy and PANI‐2mLPPy ER fluids at shear rate 0.1 s⁻¹ is 36.6 and 28.5 under electric field strength E = 3 kV/mm, respectively. Low leaking current density is observed even at high electric field strength and wide plateau region appeared, which show a strong ER activity for the PANI/PPy composite nanofibers. The results also indicate that the PANI/PPy composite particles have distinctly enhanced ER effect compared with the pure PANI and PPy particles under electric stimuli. The significantly improved ER property of PANI/PPy‐based ER fluid is ascribed to the enhanced interfacial polarization. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46289.     

The morphology and conductivity of polypyrrole/polyurethane alloy films

Polymeric composites with conductivities ranging from 10^–4 to 1 S cm^–1 were prepared by electrochemically polymerizing pyrrole in a matrix of polyurethane. The polypyrrole/polyurethane alloy films obtained were characterized by element analysis, electron microscopy and electrical conductivity measurements. The morphology of the films depended on the solvent, the electrolyte and the current density. The mechanism of the electrochemical polymerization showed that PPy grew in a treelike structure, with molecular chains extending from the electrode surface into the solution. The transition temperature of the PPy/PU increased with the PPy content.     

Electrical actuation of ionic hydrogels based on polyvinyl alcohol grafted with poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid‐co‐acrylonitrile) chains

Novel electrically conducting composite materials consisting of poly(pyrrole) (PPy) nanoparticles dispersed in a poly(vinyl alcohol)‐g‐poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid‐co‐acrylonitrile) hydrogels were prepared within the polymer matrix by in situ polymerization of pyrrole. The conversion yield of pyrrole into PPy particles was determined gravimetrically while structural confirmation of the synthesized polymer was sought by Fourier Transform Infrared (FTIR) and UV‐visible spectroscopy. The morphology of PPy nanoparticles containing hydrogel matrix was investigated by Scanning Electron Microscopy (SEM) analysis. Electrical conductivity of nanocomposite hydrogels of different compositions was determined by LCR meter while electroactive behavior of nanocomposite hydrogels swollen in electrolyte solutions was investigated by effective bend angle measurements. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

Conducting poly(styrene‐co‐divinylbenzene)/polypyrrole PolyHIPE composite foam prepared by chemical oxidative polymerization

Conducting poly(styrene‐co‐divinylbenzene)/polypyrrole (PPy) polyHIPE (polymerized high internal phase emulsion) composite foams were synthesized via chemical oxidative polymerization method. The effect of solvent and dopant type on the surface morphology and electrical conductivity of composite foams has been investigated. SEM micrographs showed that the morphology of PPy thin film on the internal surface of poly(styrene/divinylbenzene) (poly(St‐co‐DVB) polyHIPE support foam strongly depends on the solvent and dopant type used. Incorporation of dodecylbenzene solfunic acid‐sodium salt (DBSNa) as a dopant in chloroform solvent resulted in formation of a PPy thin film with higher molecular compact structure and electrical conductivity on the support foam as compared to other solvents and another dopant used. Fourier‐transform infrared spectroscopy was used to correlate the electrical conductivity of composite foams to their PPy structural parameters. As expected, the extended conjugation length of PPy in the presence of DBSNa dopant is the main reason for higher electrical conductivity of resultant composite foam. Electrical conductivity measurements revealed that the chemical aging of various conducting foams follows the first‐order kinetic model, which is a representative of a reaction‐controlled aging mechanism. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Simultaneous organic and nutrient removal from municipal wastewater by BSACNR process

Biological nutrient removal was investigated under a biological synthetic activated ceramic nutrient removal (BSACNR) process. Tests were made to establish whether organic compounds and nutrients (N, P) from municipal wastewater were eliminated effectively in a lab-scale BSACNR process by increasing the hydraulic retention time (HRT) from 4 hr to 10 hr. In the system, synthetic activated ceramic (SAC) media were packed in each reactor for attached growth of both nitrifying bacteria and denitrifying bacteria; the sludge of the clarifier was returned to the anaerobic reactor to release phosphate. In this configuration, nitrification, denitrification and phosphorus removal could be performed at their respective conditions. The influent was synthetic wastewater, and the mean concentration of COD, NH⁺ ₄ -N and T-P in the influent was about 200 mg/L, 20 mg/L and 8 mg/L, respectively. At a total HRT of the system of 4-10 hr, the system worked successfully obtaining the removal of COD, NH⁺ ₄-N, T-N and T-P: 90.5-97.5%, 72.9-94.4%, 56.5-73.7% and 36.0-61.1%, respectively. The results of this research show that a biological synthetic activated ceramic nutrient removal (BSACNR) process packed with SAC media could be applicable for treatment of organic and nutrient from municipal wastewater.     

The characterization of polyaniline and polypyrrole composites by pyrolysis mass spectrometry

In this work, direct insertion probe pyrolysis mass spectrometry technique was applied to investigate the thermal and structural characteristics of electrochemically prepared polyaniline (PANI), polypyrrole (PPy), and their composites/copolymers synthesized either by electrochemical polymerization of pyrrole on PANI‐coated electrode (PANI/PPy) or by coating PANI on PPy (PPy/PANI) in H₂SO₄ solutions. It has been determined that the polymer first coated on the electrode degraded to a certain extent during the polymerization of the second. The extent of degradation was greater for PPy and increased with the increase in acid concentration. On the other hand, the detection of mixed dimers confirmed copolymer formation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and characterization of polyaniline–polypyrrole composite from polyaniline dispersions

Polyaniline–polypyrrole (PANI‐PPy) composite was prepared by in situ polymerization of pyrrole in PANI dispersion using FeCl₃·6H₂O as oxidant and sodium dodecyl benzene sulfonate (SDBS) as surfactant. Different synthesis conditions of PANI dispersion including the relative concentration of aniline and SDBS and the amount of acid (HCl) on the morphology and conductivity of the resulting composites were investigated. Fourier transformation infrared (FTIR) spectra, X‐ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), X‐ray diffraction (XRD) patterns, and contact angles of the composites showed there existed certain interaction between PANI (or PANI‐SDBS) and PPy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3523–3529, 2007     

Anaerobic/aerobic sequential treatment of a cotton textile mill wastewater

The treatment of a wastewater taken from a cotton textile mill was investigated using an anaerobic/aerobic sequential system during an operational period of 87 days. The process units consisted of an upflow anaerobic sludge blanket (UASB) reactor and a continuous stirred tank reactor (CSTR). Wastewater characterization was performed before feeding the reactor system. Glucose‐COD, and azo dyes were added to the textile wastewater for comparative purposes in the final period of operation. The pH values in the effluent of the UASB reactor were suitable for optimal anaerobic treatment in all runs. The biodegradable part of the COD in wastewater was removed effectively, with the anaerobic stage improving the biodegradability of wastewater entering the aerobic stage. The UASB reactor permitted COD and color removals of 9–51% and 46–55%, respectively, at a hydraulic retention time (HRT) of 30 h. COD removal efficiencies were between 40 and 85% and color removal efficiencies were 39–81% in normal and artificially‐colored wastewaters at a total HRT of 5.75 days in the UASB/CSTR reactor system. Benzidine produced from the cleavage of azo bond in the anaerobic stage was effectively removed in the aerobic stage, and was identified by comparison of its HPLC spectrum with that of an authentic specimen. Copyright © 2004 Society of Chemical Industry