Synthesis and characterization of electrically conducting copolymers based on biphenyl and thiophene

New electrically conducting copolymers based on biphenyl and thiophene in a form of film were synthesized by electropolymerization using potentiostatic conditions and the corresponding homopolymers, polyphenylenes, and polythiophenes, for comparison reasons. Different values of applied potential were used, to study its effect on the structure, morphology, and electrical conductivity of the films. From the analysis of the current‐time curves, it was found that the growth of the films follows layer by layer (2D) mechanism. The films were studied by FTIR, TGA, XRD, SEM‐EDAX and their electrical conductivity was determined, as well as their energy gap (E_g) by cyclic voltammetry. The copolymers had higher conductivity (appr. 1 S/cm) and lower E_g (appr. 1.2 eV) than that of the corresponding homopolymers. These materials due to their high conductivity, high stability under repetitive potential cycling, and partial solubility are candidates for electronic applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Electrochemical polymerization of p‐terphenyl in mixed electrolyte of boron trifluoride diethyl etherate and CH2Cl2

High quality poly(p‐phenylene) (PPP) film with conductivity of 0.015 S cm^?1 was synthesized electrochemically by direct anodic oxidation of p‐terphenyl (PP) oligomers in boron trifluoride diethyl etherate (BFEE) containing 37.5% CH₂Cl₂ (v/v). The oxidation onset potential of PP in this medium was measured to be only 1.23 V vs. saturated calomel electrode (SCE), which was lower than that determined in CH₂Cl₂ + 0.1 mol L^?1 Bu₄NBF₄ (1.87 V vs. SCE). As‐formed PPP films showed good electrochemical behavior, good electrochromic property and good thermal stability. The structures and morphology of doped and dedoped PPP were investigated by UV‐vis, FTIR, and Scanning electron micrographs. The infrared spectroscopic measurements for the estimation of chain lengths revealed that PPP was composed of about 10 phenyl rings. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Chemical preparation of conducting polyfuran/poly(2‐chloroaniline) composites and their properties: A comparison of their components,polyfuran and poly(2‐chloroaniline)

Conductive homopolymers and composites of poly(2‐chloroaniline) (P2ClAn) and polyfuran (PFu) were synthesized chemically in hydrous and anhydrous media, and their properties were investigated. The polymers and composites were characterized by Fourier infrared spectroscopy, ultraviolet‐visible absorption spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, magnetic susceptibility, and conductivity measurements. It was found that the PFu/P2ClAn composite is thermally more stable than both the P2ClAn/PFu composite and the homopolymers. It was determined from Gouy scale measurements that conducting mechanisms of homopolymers and composites are polaron and bipolaron in nature. It was observed that the conductivity and magnetic susceptibility values changed with a changing amount of the guest polymer in the prepared composites. The conductivity (3.21 × 10^?2 S/cm) of the P2ClAn/PFu (55.8% m/m) composite was found to be higher than the conductivities of both homopolymers (σ_PFu = 1.44 × 10^?5 S/cm; σ_P2ClAn = 1.32 × 10^?3 S/cm). It was determined that the composites synthesized had different conductivities and morphological and thermal properties from changing synthesis order. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2924–2931, 2003     

Structure and electrical properties of grafted polypropylene/graphite nanocomposites prepared by solution intercalation

A novel process was developed to prepare electrically conducting maleic anhydride grafted polypropylene (gPP)/expanded graphite (EG) nanocomposites by solution intercalation. The conducting percolation threshold at room temperature (Φ_c) of the nanocomposites was 0.67 vol %, much lower than that of the conventional conducting composites prepared by melt mixing (Φ_c = 2.96 vol %). When the EG content was 3.90 vol %, the electrical conductivity (σ) of the former reached 2.49 × 10^?3 S/cm, whereas the σ of the latter was only 6.85 × 10^?9 S/cm. The TEM, SEM, and optical microscopy observations confirmed that the significant decrease of Φ_c and the striking increase of σ might be attributable to the formation of an EG/gPP conducting multiple network in the nanocomposites, involving the network composed of particles with a large surface‐to‐volume ratio and several hundred micrometers in size, and the networks composed of the boards or sheets of graphite with high width‐to‐thickness ratio and particles of fine microscale or nanoscale sizes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1864–1869, 2003     

Electrochemical polymerization of phenanthrene in mixed electrolytes of boron trifluoride diethyl etherate and concentrated sulfuric acid

A novel high‐quality polyphenanthrene (PPH) film with electrical conductivity of 10^?1 S cm^?1 was synthesized electrochemically by direct anodic oxidation of phenanthrene in boron trifluoride diethyl etherate containing 10% concentrated sulfuric acid (v/v). The oxidation onset potential of phenanthrene in this medium was measured to be only 0.91 V versus saturated calomel electrode (SCE), which was lower than that determined in acetonitrile + 0.1 mol L^?1 Bu₄NBF₄ (1.56 V versus SCE). As‐formed PPH films from this medium showed good electrochemical behavior and stability. De‐doped PPH films were thoroughly soluble in dimethylsulfoxide or CHCl₃. The structure and morphology of the polymer were investigated using UV‐visible and Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy. FTIR and ¹H NMR spectra showed that the PPH was grown via the coupling of the monomer mainly at the C₄, C₅, C₉ and C₁₀ positions. Fluorescence spectral studies indicated that PPH was a blue‐green light emitter. Copyright © 2007 Society of Chemical Industry     

Photo‐induced protonation and conductivity of polyaniline/poly(ethylene glycol) and polyaniline/[poly(ethylene glycol)‐grafted polyaniline] composites

Composites of polyaniline in its emeraldine base form (PANI‐EB) and photo‐acid generators (PAG) show an increase in conductivity upon photo‐irradiation due to the protonation of PANI‐EB. Such materials may be utilized to fabricate conducting patterns by photo‐irradiation. However, the conductivity obtained by direct irradiation of PANI‐EB/PAG composites was normally quite low (<10^?3 S/cm) due to aggregation of highly loaded PAG. In this work, poly(ethylene glycol) (PEG), which is a proton transfer polymer, was added to PANI‐EB/PAG. Results showed that addition of low M_w (550) PEG significantly enhance the photo‐induced conductivity. Conductivities as high as 10^?1–10⁰ S/cm were observed after photo‐irradiation. This conductivity is comparable to that of PANI‐salt synthesized by oxidizing aniline in the presence of an acid. High M_w (8000) PEG is much less effective than PEG 550, which is attributed to its lower compatibility with PANI. PEG‐grafted PANI (N‐PEG‐PANI) was also studied as an additive. Composites of PANI‐EB and N‐PEG‐PANI showed conductivity as high as 10² S/cm after treatment with HCl vapor. The photo‐induced conductivity of the N‐PEG‐PANI/PANI‐EB/PAG composite reached 10^?2–10^?1 S/cm. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The electrical properties of boron‐containing poly(vinyl alcohol) derived ceramic organic semiconductor

The direct and alternating current conductivity, space charge limited current, and thermoelectrical properties of boron‐containing poly(vinyl alcohol)‐derived ceramic have been investigated. The electrical conductivity of the sample increases with increase in temperature and the room temperature conductivity of the sample was found to be 3.82 × 10^?5 S/cm. The electrical conductivity and thermoelectric power results suggest that the PVAB polymer has p‐type electrical conductivity. The current–voltage characteristics indicate that at higher voltages, the space charge limited conductivity mechanism is dominant in the PVAB sample. The electronic parameters such as the position of the Fermi level bottom of the conduction band, E_F, the density of states in conduction band N_c, effective mass of holes m_s were found to be 0.44 eV, 2.12 × 10²⁵ m^?3, and 0.59 m_o, respectively. Alternating current conductivity results suggest that the correlated barrier hopping conductivity is dominant in AC conductivity mechanism of the sample. The imaginary part of the dielectrical modulus at different temperatures shows a relaxation peak, indicating a temperature‐dependent non‐Debye relaxation. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

A Novel Alkyl Sulphobetaine Gemini Surfactant Based on S‐triazine: Synthesis and Properties

A series of alkyl sulphobetaine Gemini surfactants C_n‐GSBS (n = 8, 10, 12, 14, 16) was synthesized, using aliphatic amine, cyanuric chloride, ethylenediamine, N,N′‐dimethyl‐1,3‐propyldiamine and sodium 2‐chloroethane sulfonate as main raw materials. The chemical structures were confirmed by FT‐IR, ¹H NMR and elemental analysis. The Krafft points differ markedly with different carbon chain length, for C₈‐GSBS, C₁₀‐GSBS and C₁₂‐GSBS are considered to be below 0 °C and C₁₄‐GSBS, C₁₆‐GSBS are higher than 0 °C but lower than room temperature. Surface‐active properties were studied by surface tension and electrical conductivity. Critical micelle concentrations were much lower than dodecyl sulphobetaine (BS‐12) and decreased with increasing length of the carbon chain from 8 to 16, and can reach a minimum as low as 5 × 10^?5 mol L^?1 for C₁₆‐GSBS. Effects of carbon chain length and concentration of C_n‐GSBS on crude oil emulsion stability were also investigated and discussed.     

Preparation of interfacially compatibilized PP‐EPDM thermoplastic vulcanizate/graphite nanocomposites: Effects of graphite microstructure upon morphology,electrical conductivity,and melt rheology

Electrically conductive PP/EPDM dynamically crosslinked thermoplastic vulcanizate (TPV)/expanded graphite (EG) has been successfully prepared via melt compounding of maleic anhydride grafted polypropylene (PP‐g‐MA)/EG masterbatch and a commercially available TPV material. Correlation between graphite microstructure, and electrical conductivity as well as melt rheological behavior has been studied. Natural graphite flake (NGF), graphite intercalated compound (GIC), and exfoliated graphite (EG) have been employed and compared. Scanning electron microscopy (SEM) showed the presence of 100–200 nm nanolayers in the structure of PP‐g/EG masterbatches, whereas thinner platelets (1.5–2.5 nm) were revealed by transmission electron microscopy (TEM). Better dispersion of the graphite nanolayers in the microstructure of TPV/PP‐g‐MA/EG composite was verified, as the 7.3 Å spacing between the aggregated graphite nanolayers could not be observed in the XRD pattern of this material. TPV/PP‐g/EG nanocomposites exhibited much lower conductivity percolation threshold (φ_c) with increased conductivity to 10^?5 S/cm at EG wt % of 10. Higher nonlinear and nonterminal melt rheological characteristics of dynamic elastic modulus (G′) at low frequency region was presented by the TPV/PP‐g/EG nanocomposites, indicating the formation of nanoscopic conducting multiple networks throughout the continuous TPV matrix. Maleated PP was found to be much more effective in separating EG nanolayers which is attributed to the higher interfacial interaction between PP‐g‐MAH and EG, synergized with its multiporous structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrical properties of diphenyldiacetylene annealed under elevated pressure

A unique class of conjugated compounds composed of the derivative of condensed polycyclic aromatic compound with the phenyl group and diphenyldiacetylene oligomer was synthesized by annealing of diphenyldiacetylene under elevated pressure. The effect of annealing pressure on the conductivity of the compounds was studied. The total conductivity of the compound decreased with a decrease of frequency, approaching a constant value (dc conductivity: C_dc). The dc conductivity of the compound increased from below 10^?15 to 10 S cm^?1 with increasing annealing pressure. The dc conductivity of the oligomer was below 10^?15 S cm^?1 and that of the derivative increased from 10^?8 to 10 S cm^?1 with decreasing H/C (H/C:0.45–0.04). The conduction of the conjugated compound was electronic. The temperature coefficient of those dc conductivities was positive, with an approximately linear relation between In (C_dcT^0.5) and (1/T)^0.25, where T is the temperature. The ac conductivities C_ac were proportional to temperature and frequency f and had the following equation C_ac = Tf^S, S = 0.67–0.75. These results showed that the conduction mechanism can be explained by the hopping in a manifold of states at the Fermi level. © 1994 John Wiley & Sons, Inc.     

Direct low‐potential electropolymerization of 9,10‐dihydrophenanthrene in boron trifluoride diethyl etherate

High‐quality poly(9,10‐dihydrophenanthrene) (PPh) with good fluorescence properties was synthesized electrochemically by the direct anodic oxidation of 9,10‐dihydrophenanthrene in boron trifluoride diethyl etherate (BFEE). PPh films obtained from BFEE‐based electrolytes showed good electrochemical behavior and good thermal stability with an electrical conductivity of 2.2 × 10^?3 S/cm; this indicated that BFEE was a better medium for the electrosyntheses of PPh films. Dedoped PPh films were soluble in CH₂Cl₂, dimethylformamide, and dimethyl sulfoxide. The structure and morphology of the polymer were also characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, ¹H‐NMR spectroscopy, and scanning electron microscopy, respectively, which indicated the polymerization mainly occurred at the C₍₂₎ and C₍₇₎ positions. Fluorescent spectral studies indicated that PPh was a good blue‐light emitter. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,characterization, and comparison of self‐doped,doped, and undoped forms of polyaniline,poly(o‐anisidine), and poly[aniline‐co‐(o‐anisidine)]

Polyaniline (PANI), poly(o‐anisidine), and poly[aniline‐co‐(o‐anisidine)] were synthesized by chemical oxidative polymerization with ammonium persulfate as an oxidizing reagent in an HCl medium. The viscosities, electrical conductivity, and crystallinity of the resulting polymers (self‐doped forms) were compared with those of the doped and undoped forms. The self‐doped, doped, and undoped forms of these polymers were characterized with infrared spectroscopy, ultraviolet–visible spectroscopy, and a four‐point‐probe conductivity method. X‐ray diffraction characterization revealed the crystalline nature of the polymers. The observed decrease in the conductivity of the copolymer and poly(o‐anisidine) with respect to PANI was attributed to the incorporation of the methoxy moieties into the PANI chain. The homopolymers attained conductivity in the range of 3.97 × 10^?3 to 7.8 S/cm after doping with HCl. The conductivity of the undoped forms of the poly[aniline‐co‐(o‐anisidine)] and poly(o‐anisidine) was observed to be lower than 10^?5 J/S cm^?1. The conductivity of the studied polymer forms decreased by the doping process in the following order: self‐doped → doped → undoped. The conductivity of the studied polymers decreased by the monomer species in the following order: PANI → poly[aniline‐co‐(o‐anisidine)] → poly(o‐anisidine). All the polymer samples were largely amorphous, but with the attachment of the pendant groups of anisidine to the polymer system, the crystallinity region increased. The undoped form of poly[aniline‐co‐(o‐anisidine)] had good solubility in common organic solvents, whereas doped poly[aniline‐co‐(o‐anisidine)] was moderately crystalline and exhibited higher conductivity than the anisidine homopolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Electrical Conductivity of SiOCN Ceramics by the Powder‐Solution‐Composite Technique

SiOCN ceramics have been prepared by the polymer pyrolysis method. The preceramic polymers were synthesized from a polysiloxane cross‐linked with two different N‐containing compounds: a silazane or a ternary amine. The corresponding SiOCN ceramics were obtained by pyrolysis in nitrogen atmosphere at five different temperatures from 1000°C to 1400°C. The electrical conductivity of the powdered SiOCN ceramic samples was determined by the powder‐solution‐composite technique. The results show an increase in room temperature AC conductivity of three orders of magnitude, from ≈10^?5 (S/cm) to ≈10^?2 (S/cm), with increasing pyrolysis temperature from 1000°C to 1400°C. Furthermore, the electrical conductivity of the amine‐derived SiOCN is three to five times higher than that of the silazane‐derived ceramic at each pyrolysis temperature. The combined structural study by Raman spectroscopy and chemical analysis suggests that the increase of electrical conductivity with the pyrolysis temperature is due to the sp³‐to‐sp² transition of the amorphous carbon phase. The higher conductivity of the amine‐derived SiOCN is also discussed considering features like the volume% of the free‐carbon phase and its possible N‐doping.     

Investigation of charge transport properties in conducting copolymers of aniline with 3‐aminobenzenesulfonic acid for their applications as antistatic encapsulation materials blended with low‐density polyethylene

The electrostatic charge dissipative (ESD) properties of conducting self‐doped and PTSA-doped copolymers of aniline (AA), o‐methoxyaniline (methoxy AA) and o‐ethoxyaniline (ethoxy AA) with 3‐aminobenzenesulfonic acid (3‐ABSA) blended with low‐density polyethylene (LDPE) were investigated in the presence of external dopant p‐toluenesulfonic acid (PTSA). Blending of copolymers with LDPE was carried out in a twin‐screw extruder by melt blending by loading 1.0 and 2.0 wt% of conducting copolymer in the LDPE matrix. The conductivity of the blown polymers blended with LDPE was in the range 10^?12–10^?6 S cm^?1, showing their potential use as antistatic materials for the encapsulation of electronic equipment. The DC conductivity of all self‐doped homopolymers and PTSA‐doped copolymers was measured in the range 100–373 K. The room temperature conductivity (S cm^?1) of self‐doped copolymers was: poly(3‐ABSA‐co‐AA), 7.73 × 10^?4; poly(3‐ABSA‐co‐methoxy AA), 3.06 × 10^?6; poly(3‐ABSA‐co‐ethoxy AA), 2.99 × 10^?7; and of PTSA‐doped copolymers was: poly(3‐ABSA‐co‐AA), 4.34 × 10^?2; poly(3‐ABSA‐co‐methoxy AA), 9.90 × 10^?5; poly(3‐ABSA‐co‐ethoxy AA), 1.10 × 10^?5. The observed conduction mechanism for all the samples could be explained in terms of Mott's variable range hopping model; however, ESD properties are dependent upon the electrical conductivity. The antistatic decay time is least for the PTSA‐doped poly(3‐ABSA‐co‐AA), which has maximum conductivity among all the samples. © 2013 Society of Chemical Industry     

Enhanced thermoelectric performance of n‐type Bi2O2Se by Cl‐doping at Se site

The n‐type polycrystalline Bi₂O₂Se_1?xCl_x (0≤x≤0.04) samples were fabricated through solid‐state reaction followed by spark plasma sintering. The carrier concentration was markedly increased to 1.38×10²⁰ cm^?3 by 1.5% Cl doping. The maximum electrical conductivity is 213.0 S/cm for x=0.015 at 823 K, which is much larger than 6.2 S/cm for pristine Bi₂O₂Se. Furthermore, the considerable enhancement of the electrical conductivity outweighs the moderate reduction of the Seebeck coefficient by Cl doping, thus contributing to a high power factor of 244.40 μ·WK^?2·m^?1 at 823 K. Coupled with the intrinsically suppressed thermal conductivity originating from the low velocity of sound and Young's modulus, a ZT of 0.23 at 823 K for Bi₂O₂Se_0.985Cl_0.015 was achieved, which is almost threefold the value attained in pristine Bi₂O₂Se. It reveals that Se‐site doping can be an effective strategy for improving the thermoelectric performance of the layered Bi₂O₂Se bulks.     

Poly(2‐) and (3‐aminobenzoic acids) and their copolymers with aniline: Synthesis,characterization, and properties

Poly(2‐aminobenzoic acid) and poly(3‐aminobenzoic acid) were synthesized by chemical polymerization of the respective monomers with aqueous 1M hydrochloric acid and 0.49M sodium hydroxide, using ammonium persulfate as an oxidizing agent. In addition, polymerization in an acid medium was carried out in the presence of metal ions, such as Cu(II), Ni(II), and Co(II). Poly(2‐aminobenzoic acid‐co‐aniline) and poly(3‐aminobenzoic acid‐co‐aniline) were synthesized by chemical copolymerization of aniline with 2‐ and 3‐aminobenzoic acids, respectively, in aqueous 1M hydrochloric acid. The copolymers were synthesized at several mole fractions of aniline in the feed and characterized by UV–visible and FTIR spectroscopy, the thermal stability, and the electrical conductivity. Metal ions, such as Cu(II), Ni(II), and Co(II), were incorporated into homo‐ and copolymers by the batch method. The percentage of metal ions in the polymers was higher in the copolymers than in the homopolymers. The thermal stability of the copolymers increased as the feed mole fraction of aniline decreased and varied with the incorporation of metal ions in the polymers. The electrical conductivity of the homo‐ and copolymers was measured, which ranged between 10^?3 and 10^?10 S cm^?1. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2641–2648, 2003     

SiCN ceramics with controllable carbon nanomaterials for electromagnetic absorption performance

Different kinds of carbon nanomaterials, free carbon (C_free), graphene, and N-containing graphene (NG), in single-source-precursors-derived SiCN ceramics, were in situ generated by modifying polysilazane with divinylbenzene, dopamine hydrochloride and melamine, respectively. Adjusting the carbon source brings phase structure and electromagnetic wave absorption (EMA) properties differences of SiCN/C ceramics. In situ C_free enhances the EMA capacity of SiCN ceramics by improving their electrical conductivity of 9.2 × 10⁻⁴ S/cm. The electrical conductivity of SiCN ceramics with 2D graphene sheets balloons to 2.5 × 10⁻³ S/cm, causing poor impedance match thus leading to a worse EMA performance. In situ NG in SiCN ceramics has a low electrical conductivity of 5.6 × 10⁻⁸ S/cm, making for excellent impedance match. The corrugated NG boosts dielectric loss, interfacial, and dipole polarization. NG-SiCN nanocomposites possess an outstanding EMA performance with RL_min of −61.08 dB and effective absorption bandwidth of 4.05 GHz, which are ∼2.4 times lower and ∼4 times higher than those of SiCN, respectively.     

Conducting blends obtained from maleic acid/dodecylhydrogensulfate‐doped polyaniline and polyvinyl chloride by solution processing

Solution processible polyaniline, obtained by our newly developed method via emulsion polymerization in the presence of maleic acid and sodium lauryl sulfate with benzoyl peroxide as the oxidizing/polymerizing agent, has been used for the fabrication of conductive blends with poly(vinyl chloride) (PVC), covering the conductivity range from 10^?5 to 5 × 10^?3 S/cm and showing the percolation threshold for the electrical conductivity f_p = 0.039. The fabricated blends combine good mechanical properties with enhanced electrical conductivity, since up to conducting phase content f = 0.231, their mechanical properties remain essentially the same and characteristic of pure PVC. Differential scanning calorimetry (DSC) measurements show a single glass‐transition temperature (T_g) increasing with growing content of the rigid conductive phase in the blend. This effect can be taken as an evidence of good miscibility of both components of the blend with phase separation at a submicrometric level. The latter has been confirmed by scanning electron microscopy studies showing a necklace‐like morphology which assures the continuity of the conductive phase. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1113–1119, 2007     

Synthesis and physicochemical characterization of poly(azomethine)esters containing aliphatic/aromatic moieties: Electrical studies complemented by DFT calculation

A conducting poly(azomethine)ester was prepared by solution phase polycondensation of a preformed Schiff base, 4‐((4‐(4‐(4‐hydroxybenzlideneamino) phenoxy)phenylimino)methyl)phenol and isophthaloyl chloride (I). Different aliphatic/aromatic moieties were incorporated for examining their effect on the electronic properties of material. The resulting polymers (10^?4 to 25 S cm^?1) were doped with silver (10^?6 to 10^?2 S cm^?1) and blended with polyaniline (10^?1 to 13.4 S cm^?1) to enhance their electrical conductivity. Polymer/polyaniline blends had superior conductivity even at low polyaniline concentration relative to the silver‐doped chains. The data obtained experimentally were complemented by density function theory at the 6–31G/B3LYP level. The results showed that ΔE along with lowest unoccupied molecular orbital and highest occupied molecular orbital electron density accounts for the electrical properties. Spectroscopic (¹HNMR, FTIR) and elemental analysis were used for structural elucidation. Structure–property relation in term of WXRD, SEM‐EDX, atomic force microscope, LLS, and thermal behavior was studied. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40698.     

Preparation and properties of waterborne polyurethane/polyaniline codoped with dodecyl benzene sulfonic acid and hydrochloric acid blends

A conductive poly(aniline codoped with dodecyl benzene sulfonic acid and hydrochloric acid) [PANI‐D/H, yield: 32.2%, intrinsic viscosity ([η]): 1.39 dL/g, electrical conductivity: 7.3 S/cm] was synthesized by chemical oxidative polymerization from aniline‐dodecylbenzene sulfonic acid salt (A‐DS)/aniline‐hydrochloric acid salt (A‐HS) (6/4M ratio) in an aqueous system. Waterborne polyurethane (WBPU) dispersion obtained from isophorone diisocyanate/poly(tetramethylene oxide)glycol/dimethylol propionic acid/ethylene diamine/triethylene amine/water was used as a matrix polymer. The blend films of WBPU/PANI‐D/H with various weight ratios (99.9/0.1–25/75) were prepared by solution blending/casting. Effect of PANI‐D/H content on the mechanical property, dynamic mechanical property, hardness, electrical conductivity, and antistaticity of WBPU/PANI‐D/H blend films was investigated. The dynamic storage modulus and initial tensile modulus increased with increasing PANI‐D/H content up to 1 wt %, and then it was significantly decreased about the content. With increasing PANI‐D/H content, the glass transition temperature of soft segment (T_gs) and hard segment (T_gh) of WBPU/PANI‐D/H blend films were shifted a bit to lower the temperature. The tensile strength and hardness of WBPU/PANI‐D/H blend films increased a little with increasing PANI‐D/H content up to 0.5 wt %, and then it was dramatically decreased over the content. The elongation at break of WBPU/PANI‐D/H decreased with an increase in PANI‐D/H content. From these results, it was concluded that 0.5–1 wt % of PANI‐D/H was the critical concentration to reinforce those various properties of WBPU/PANI‐D/H blend films prepared in this study. The electrical conductivity of WBPU/ultrasonic treated PANI‐D/H (particle size: 0.7 μm) blend films prepared here increased from 4.0 × 10^?7 to 0.33 S/cm with increasing PANI‐D/H content from 0.1 to 75 wt %. The antistatic half‐life time (τ_1/2) of pure WBPU film was about 110 s. However, those of WBPU/ultrasonic treated PANI‐D/H blend films (τ_1/2: 8.2–0.1 s, and almost 0 s) were found to decrease exponentially with increasing PANI‐D/H content (0.1–9 wt %, and above 9 wt %). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 700–710, 2004