Composites based on poly(ethylene terephthalate) fibers with polyaniline. II. The effect of the growth of the polyaniline molecules during the polymerization in the morphology of the PET substrate

PET fibers of different drawn ratios were used as substrates to produce composites with PANi. The influence of the growth of the polyaniline molecules in the structure of the fibers previously pretreated in the presence of aniline at different conditions were studied by different characterization techniques (differential scanning calorimetry, X‐ray scattering, dynamic and mechanical thermal analysis, sonic modulus, and scanning electron microscopy). The polymerization of the aniline inside the fiber substrates modified the structure of the fibers. In the case of the drawn fiber substrates the growth of the PANi molecules occurred mainly in the interfibrillar regions, which promoted reorganization of the preexisting crystals such as defect elimination (mainly in the interface of these regions with the lamellar regions) and at same time reorientation of their amorphous and crystalline regions. Also, due to this reorientation process the crystals became not only bigger and more perfect, but also they became more homogeneous. In the case of the undrawn fiber substrates, due to the lack of previous orientation, the growth of the PANi molecules would be occurring in the amorphous interlamellar regions only. Finally, the use of fibers with different drawn ratios as substrates for the composites was essential to reach such conclusions. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2346–2362, 2000     

X‐ray photoelectron spectroscopy and electrical conductivity of polyaniline doped with dodecylbenzenesulfonic acid as a function of the synthetic method

X‐ray photoelectron spectroscopy (XPS) has been employed to investigate the protonation degree of polyaniline doped with dodecylbenzenesulfonic acid (Pani. DBSA) obtained by different synthetic methods. The protonation degree has been compared to electrical conductivity. Pani.DBSA prepared through the redoping process in an agate mortar displays conductivity values within the range of 1 S/cm. A protonation level of 48% with almost all imine groups being protonated. Pani.DBSA was also synthesized by oxidative polymerization of aniline in the presence of DBSA, which acts simultaneously as a surfactant and as protonating agent. This in situ doping polymerization was carried out in aqueous or toluene media. In both cases, protonation degrees higher than 50% have been achieved, indicating that a substantial portion of amine units have also been protonated. Higher doping degree has been achieved by aqueous dispersion polymerization of aniline. The C/N and S/N molar ratios obtained by XPS analysis indicate that the polyaniline chains obtained by in situ polymerization are protonated by both sulfonate and hydrogen sulfate anions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 556–565, 2001     

Synthesis and properties of oxalic acid-doped polyaniline

Conductive polyaniline was synthesized in aqueous 1.0M oxalic acid containing 0.1 M aniline by electrochemical and chemical oxidation and characterized by conductivity, solubility, ultraviolet and infrared spectroscopy, and cyclic voltammetry. The solubility experiments showed that the solubility of oxalic acid-doped polyaniline in dimethylsulfoxide and dimethylformaide increased to a certain extent. The soluble part of the polyaniline was free from impurities such as quinones. Cyclic voltammetric studies in oxalic acid medium revealed that aniline exhibited a similar behaviour to that in H₂SO₄ and the polymerization rate was much slower than that in H₂SO₄.     

Electrically conductive hydrogel composites made of polyaniline nanoparticles and poly(N-vinyl-2-pyrrolidone)

A novel electrically conductive composite material, consisting of polyaniline (PANI) nanoparticles dispersed in a polyvinyl pyrrolidone (PVP) hydrogel, was prepared ‘in situ’ by water dispersion polymerisation (DP) of aniline using PVP as steric stabiliser, followed by γ-irradiation induced crosslinking of the PVP component. Conversion yield of aniline into PANI particles was determined via HPLC and gas chromatography, while structural confirmation of the synthesised polymer was sought by FTIR. Morphology and dimensions of PANI particles into the coloured, optically transparent hydrogel was determined by electronic microscopy; moreover, swelling behaviour of composite hydrogels in different buffer solutions was investigated by gravimetric measurements and compared to that of pure PVP hydrogels.Cyclic voltammetry experiments were carried out both on these hydrogels and on the parent aqueous dispersions, at different pH values of the suspending/swelling medium, while conductivity of the composite hydrogels was derived from Impedance Spectroscopy; in both cases results were compared to those relative to hydrogels containing commercial-grade PANI particles.     

含导电聚苯胺类锂离子电池复合材料的现状及发展趋势

导电聚苯胺（PANI）是近十年来研究最多的导电聚合物,具有比容量高、氧化还原可逆性好、电导率高、合成方法简单、成本低等特点,在化学电源和超级电容器中的应用最为广泛。导电聚苯胺复合材料的合成方法主要分为：原位复合法、共混法、自组装和电化学复合法等。导电聚苯胺复合材料可作为高能物质用于研发电极材料,但目前利用导电聚苯胺对锂离子电池三元正极材料进行修饰改性的研究较少。综述了导电聚苯胺及其复合材料的热电化学性能,重点对导电聚苯胺/锂离子电池复合正极材料的性能进行了阐述。最后对导电聚苯胺复合材料的应用和研究方向进行了总结,并简述了导电聚苯胺包覆改性LiNi_1-x-yCo_xMn_yO₂复合材料的应用和展望。     

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     

聚苯胺/聚丙烯酸(酯)复合材料制备方法研究进展

聚苯胺/聚丙烯酸(酯)复合材料具有良好的可加工性、成膜性、附着力、电学性能以及防腐蚀性能。本文回顾了国内外在聚苯胺/聚丙烯酸(酯)混合复合材料和聚苯胺/聚丙烯酸(酯)聚合复合材料等方面的研究工作, 介绍了各种聚苯胺/聚丙烯酸(酯)复合材料的制备方法、性能及应用, 并比较了这些制备方法的优缺点。分析结果表明:混合复合法工艺简单、易于控制、适用范围广;聚合复合法将聚苯胺和聚丙烯酸(酯)在分子水平上结合, 使聚苯胺和聚丙烯酸(酯)的优异性能得以综合发挥;而互穿网络聚合法通过网络互穿实现了两种差别较大的分子链的强制相溶。提出在分子水平上的复合是聚苯胺/聚丙烯酸(酯)复合材料研究的主要发展方向。     

Electrically conductive nanocomposites of polyaniline with poly(vinyl alcohol) and methylcellulose

Electrically conductive nanocomposites of HCl‐doped polyaniline (PANI–HCl) nanocolloid particles with water‐soluble and film‐forming polymers such as poly(vinyl alcohol) (PVA) and methylcellulose (MC) were prepared by the redispersion of preformed MC‐coated submicrometric PANI–HCl particles in PVA and MC solutions under sonication for 1 h and the casting of the films from the dispersions followed by drying. The submicrometric polyaniline (PANI) particles were prepared by the oxidative dispersion polymerization of aniline in an acidic (1.25M HCl) aqueous ethanol (30 : 70) medium with MC as a steric stabilizer. The particles contained 4.7 wt % MC and had a conductivity of 7.4 S/cm. They had an oblong shape of 203 nm (length) and 137 nm (breadth). Sonication broke the oblong‐shaped particles to sizes of ～10 nm in the PVA matrix and ～60 nm in the MC matrix. The electrical conductivity of these films was measured, and the percolation threshold was determined. The composites had the characteristics of a low percolation threshold at a volume fraction of PANI of 2.5 × 10^?2 in the PVA matrix and at a volume fraction of 3.7 × 10^?2 in the MC matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The role of conductive pathways in the conductivity and rheological behavior of poly(methyl methacrylate)–graphite composites

Up to now, research on the dynamic process of conductive network formation has tended to focus on composite particles with one‐dimensional geometry, such as carbon black and carbon nanotubes. However, studies on this subject based on fillers with two‐dimensional structure, such as graphite, are rare in the literature. In this work, the dynamic percolation and rheological properties of poly(methyl methacrylate) (PMMA)–graphite composites under an electric field were investigated. The activation energies of conductive network formation and polymer matrix mobility were calculated from the temperature dependence of the percolation time and the zero‐shear viscosity. It was found that the activation energy calculated from the zero‐shear viscosity was not influenced by the electric field in the concentration range investigated, but the electric field had an effect on the activation energy calculated from the percolation time. This finding emphasizes that the electrical and rheological properties have different physical origins. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43810.     

Miscible blends of biobased poly(lactide) with poly(methyl methacrylate): Effects of chopped glass fiber incorporation

Poly(lactide) (PLA) and poly(methyl methacrylate) (PMMA) are melt compounded with chopped glass fiber using laboratory scale twin‐screw extrusion. Physical properties are examined using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), tensile testing, impact testing, X‐ray computed tomography (CT) scanning, and field emission scanning electron microscopy (FE‐SEM). Molecular weight is determined using gel permeation chromatography (GPC). Miscibility of the blends is implied by the presence of a single glass transition temperature and homogeneous morphology. PLA/PMMA blends tend to show positive deviations from a simple linear mixing rule in their mechanical properties (e.g., tensile toughness, modulus, and stress at break). The addition of 40 wt % glass fiber to the system dramatically increases physical properties. Across all blend compositions, the tensile modulus increases from roughly 3 GPa to roughly 10 GPa. Estimated heat distortion temperatures (HDTs) are also greatly enhanced; the pure PLA sample HDT increases from 75 °C to 135 °C. Fiber filled polymer blends represent a sustainable class of earth abundant materials which should prove useful across a range of applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44868.     

Development of nanocomposites of bentonite with polyaniline and poly(methacrylic acid)

Nanocomposites of bentonite with polyaniline (PANI), poly(methacrylic acid) (PMAA), and poly(aniline‐co‐methacrylic acid) (PANI‐co‐PMAA) were prepared by in situ intercalative polymerization technique. The nanocomposites were characterized by FTIR and UV–visible spectroscopies, XRD, SEM, TEM, as well as TG‐DTA studies. The in situ intercalative polymerization of PANI, PMAA, and PANI‐co‐PMAA within bentonite layers was confirmed by FTIR, XRD, SEM, as well as TEM studies. XRD confirmed the intercalation of polymers and copolymer in bentonite. The average particle size of the nanocomposites was found to be in the range of 250–500 nm. The thermal stability was found be the highest for PANI‐co‐PMAA‐bentonite. The swelling behavior studies suggest that these nanocomposites hold potential for their utilization in absorption of toxic materials from waste water. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3299–3306, 2007     

Conductive blends of polyaniline with plasticized poly(methyl methacrylate)

Polyaniline (PANI) protonated with camphorsulfonic acid (CSA) and three different poly(alkylene phosphates) (PAPs) (where alkylene = pentylene, hexylene, or nonylene) was used in the fabrication of conductive polyaniline–poly(methyl methacrylate) (PMMA) blends. The lowest percolation threshold (f_p = 0.041 wt %) was obtained for the PANI(CSA)_0.5–PMMA blend plasticized with 35 wt % of dibutyl phtalate (DBPh). This blend is also very resistant against the deprotonation of its conductive phase in basic solutions of pH = 9. In the case of blends prepared with the use of PAPs as PANI dopants, the percolation threshold strongly depends on the length of the hydrophobic spacer (alkylene group) in the dopant. The percolation threshold decreases in the order PPP > PHP > PNP, whereas the resistance against deprotonation in basic solutions decreases in the following inverse order: PNP > PHP > PPP. This last observation can be rationalized by increasing contribution of hydrophobic segments in the polymeric dopant, when going from PPP to PNP, which renders polyaniline more resistance toward the penetration by aqueous basic solutions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 471–479, 1999     

Preparation and characterization of conductive poly(vinyl alcohol)/polyaniline doped by dodecyl benzene sulfonic acid (PVA/PANDB) blend films

In this study a solution‐blend method is adopted to prepare conductive poly(vinyl alcohol)/polyaniline doped by dodecyl benzene sulfonic acid (PVA/PANDB) blend films. Emeraldine base (EB)‐type polyaniline (PANI) is dissolved in N‐methyl‐2‐pyrrolidinone (NMP) and then blended with PVA/dodecyl benzene sulfonic acid (DBSA) solution by various amounts. It is found that the electrical conductivity and the thermal degradation onset temperature of the PVA/PANDB blend film are increased as the amount of EB‐type PANI solution is increased. Fourier transform infrared (FTIR) spectra show that the intensity of the characteristic peak of the functional groups in the blend film is significantly changed as the amount of EB‐type PANI is changed. From optical microscopy examination, it indicates that the amount and size of green particles are increased with increasing the amount of EB‐type PANI solution. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3415–3422, 2007     

聚苯胺/乙炔炭黑多孔类棒状复合材料的制备及电化学性质

以纳米乙炔炭黑在盐酸掺杂的反应体系中的聚集体为硬模板,原位吸附化学氧化法制备了聚苯胺/炭黑复合材料。实验结果显示,聚苯胺复合物为表面附着大量纳米颗粒的类棒状结构,且棒与棒间富有孔隙。复合材料分解温度在350℃左右。循环伏安曲线表现出该复合材料法拉第准(赝)电容有良好的电极可逆性,在5,10 mA/cm2电流密度下,单电极比电容高达376 F/g和311 F/g。     

Preparation and electroactivity of polyaniline/poly(acrylic acid) film electrodes modified by platinum microparticles

The preparation and properties of poly(acrylic acid) (PAA)-doped polyaniline (PANI) film electrodes further modified by electrodeposition of platinum particles were investigated by cyclic voltammetry and in situ conductivity measurement. The PANI/PAA film exhibits a better electroactivity and higher stability, even in solutions of lower acidity, although its polymerization rate is decreased three-fold compared to that of PANI. The conductivity of the PANI/PAA film increases by a factor of two compared to that of PANI. The effects of the carboxylic acid groups of PAA in the PANI matrix on the performance of the film are discussed. The electrocatalytic activity of PANI/PAA/Pt for reduction of hydrogen and oxidation of MeOH is higher than that of PANI modified with Pt particles alone. Characterization of the electrodes by SEM shows the platinum modification procedure yields roughly spherical catalyst particles 0.51mum in diameter dispersed throughout the polyaniline.     

Facile synthesis of hollow microspheres of polyaniline using poly(sodium 4‐styrenesulfonate) as dopant

In a conventional chemical oxidative polymerization of aniline in poly(sodium 4‐styrenesulfonate) aqueous solution, hollow microspheres of polyaniline were easily prepared, instead of common particles. The morphology of the hollow microspheres was studied and confirmed using scanning electron microscopy and transmission electron microscopy. The molecular structure, room temperature conductivities and thermal stability of the resulting polyaniline were characterized using Fourier transform infrared spectroscopy, the standard DC four‐probe method, thermogravimetric analysis and differential thermal analysis. The influence of poly(sodium 4‐styrenesulfonate) and aniline on the morphology and physical properties of the resulting polymer were investigated. The results showed that the proper ratio of poly(sodium 4‐styrenesulfonate) and aniline was a critical factor in the synthesis of hollow microspheres, which may be related to the chemical structure of poly(sodium 4‐styrenesulfonate) as polyanion and of polyaniline as polycation and the electrostatic interaction between them in the doping process. A possible formation mechanism is proposed in this work. © 2013 Society of Chemical Industry     

Facile in-situ preparation of polyaniline/graphene nanocomposites using methanesulfonic acid

Polyaniline (PANI)/graphene composites were prepared by the in-situ polymerization of aniline in a 1 M aqueous solution of methanesulfonic acid (MSA) containing graphene, which was prepared separately from graphite powders by simple sonication in MSA. Graphite powders spontaneously exfoliated to form graphene (GPM), which was then quenched with excess water, filtered, and dried to produce powders. The dried graphene powders produced were re-dispersed well in a 1 M MSA aqueous solution, in which the in-situ polymerization of aniline was performed. The resulting PANI/GPM composite had a conducting emeraldine salt (ES) form, and showed good electrical and thermal properties, compared to pure PANI prepared using a 1 M HCl solution. The PANI/GPM composite could be dissolved in a MSA solution and spin-coated in a conducting ES form of PANI. In contrast, the ES form produced from a HCl solution was insoluble in organic solvents and needed to be reduced to convert it to the emeraldine base form to produce a PANI solution. Therefore, the in-situ preparation of PANI/graphene composites using MSA provides a facile means of improving the thermal and electrical properties of PANI and its processability.     

十二烷基苯磺酸掺杂聚苯胺的制备及性能

用十二烷基苯磺酸（DBSA）的水溶液对化学合成的聚苯胺（PAn)进行掺杂,获得了导电的DBSA掺杂PAn(PAn-DBSA),通过对本征态聚苯胺（PAnEB)掺杂率的计算和电导率的测定,研究了DBSA用量及其溶液浓度对掺杂效果的影响,结果表明,当DBSA／PAnEB(摩尔比）小于0．1时,溶液浓度的影响很小,当DBSA／PAnEB大于0．2时,溶液浓度的影响非常大,而且,高浓度比低浓度对提高掺杂率和电导率更有利。热重分析表明,PAnEB,PAn-DBSA在空气中的热分解温度分别为350和250℃,表现出良好的热稳定性。     

A bio-based compatibilizer for improved interfacial compatibility in thermally conductive and electrically insulating graphite/high density poly(ethylene) composites

Graphite is a thermally conductive filler. However, when dispersed into high density poly(ethylene) (HDPE) resin, graphite particles tend to agglomerate and requires a compatibilizer to achieve desired thermal/physical properties. In this study, oleic acid (OA), a bio-based additive and polyethylene-polyamines (PEPA) were used to synthesize a new compatibilizer, PEPA-g-OA, containing numerous  NR₂ groups. The experimental results showed that PEPA-g-OA can significantly improve the compatibility between graphite particles and the HDPE matrix due to uniform dispersion of graphite in the HDPE matrix. When the graphite content was 25 wt%, the thermal conductivity of the composite recorded 1.2 W m⁻¹ K⁻¹ (three times that of neat HDPE) and the volume resistivity was 1.8 × 10⁹ Ω cm, indicating excellent electrical insulation. Compared to the composites with no graphite content, the properties of the composites with 25 wt% graphite content exhibited narrower melting and crystallization peaks, more stable mechanical properties, and higher ultraviolet aging resistance. Synthesized new bio-based compatibilizer and thermally conductive and electrically insulating composites developed in this study can be useful in different industrial fields for the preparation of the next generation composites.     

Preparation and applications of the tertiary copolymer poly(ethylene glycol) methacrylate/methyl methacrylate/diethyl allylphosphonate

A novel poly(acrylonitrile‐co‐butadiene‐co‐styrene) (ABS) antistatic and flame‐retardant agent, poly(ethylene glycol) methacrylate/methyl methacrylate/diethyl allylphosphonate (PMMD), was synthesized from poly(ethylene glycol) methacrylate, methyl methacrylate, and diethyl allylphosphonate by free‐radical precipitation polymerization in the aqueous phase to improve the antistatic and flame‐retardant performance at the same time. Through adjustments of the molar ratios of the three monomers, various antistatic, flame‐retardant copolymers (PMMD) were synthesized. The molecular structure and thermal stability of PMMD were analyzed with Fourier transform infrared spectroscopy and thermogravimetric analysis. The electrical resistivity and flame‐retardant and mechanical properties of the ABS/PMMD composites were analyzed by a ZC90 megohmmeter, an oxygen index meter, a vertical burning tester, a memory impact testing machine, and a tensile testing machine. The morphology of PMMD in the ABS blends was characterized with scanning electron microscopy. The compatibilities of PMMD and ABS were characterized by the calculation of the thermodynamic work of adhesion via the measurement of the contact angle. The results show that the antistatic and flame‐retardant performance of ABS were greatly improved by the PMMD copolymer and the mechanical properties of ABS showed little reduction. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44126.