Studies on the preparation and properties of conductive polymers. Part II. Novel method to prepare metallized plastics from metal chelates of polyamides

New metallized films were obtained by the reduction of polyamide metal chelate films with reducing agents. Polyamide metal chelates films exhibited excellent surface resistivity around 10°–10¹ Ω/cm² when treated with sodium borohydride aqueous solutions. Aqueous solutions of polyamide–formic acid with metal salts, and films prepared from those solutions, were analyzed by UV-visible and IR spectroscopy, respectively, in order to investigate and identify the structure of the polyamide metal chelates. Factors that include kinds and concentrations of metal salts, kinds and concentrations of reducing agents, and reduction time, which may affect the conductivity of metallized films, were investigated. The surfaces of these films were treated with sodium borohydride aqueous solution to form a definite metallic luster appearance. The surfaces of these conductive films were proved to be metallized, by means of ESCA analysis. The strongly adhered metal on the films was believed to be responsible for the improvement in electrical conductivity. The mechanical properties and scanning electron microscope (SEM) observations were also studied.     

Studies on the preparation and properties of conductive polymers. V. Analysis of metallized polyamide complex metal chelate films and precipitates in metal chelate solution

Metallized films were obtained by the reduction of polyamide metal chelate films with reducing agents. In the preparation of polyamide metal chelate solution, a small amount of precipitate forms when a certain stoichiometric ratio of formic acid, polyamide, and metal salts was mixed. The precipitate formation rate was affected by kinds and concentrations of metal salts, kinds and molecular weight of polyamide, and solution temperature. In addition, the precipitate formation rate affects the conducting surface metallic substance of reduced nylon/CuCl₂/NiCl₂ complex metal chelate film. The conducting surface is metallic Ni for low-molecular-weight nylon 4/CuCl₂/NiCl₂ film and metallic Cu for high-molecular-weight nylon 4/CuCl₂/NiCl₂ film reduced by NaBH₄ aqueous solution. The precipitate consists of polyamide, metal salt, and formic acid. The interaction among the polyamide, metal salt, and formic acid appears to be by means of hydrogen bonds and ionic bonds. The proposed structure of precipitate was also studied. © 1992 John Wiley & Sons, Inc.     

Studies on the preparation and properties of conductive polymers. III. Metallized polymer films by retroplating out

A novel method to prepare polymer metallized films was found by using polymer metal chelate films treated with wetted metal plates (or metal powders). The polymer metal chelate films were prepared by metal salts mixed with the polymers containing a functional group, such as poly(vinyl alcohol) (PVA), polyamide, polyacrylamide (PAAm), and polyurethane (PU). This novel method is called the retroplating-out method. Polymer metallized films exhibited low surface resistivity around 10^?1 Ω/cm² by using this novel method. The surfaces of these films were shown to be metallized by means of X-ray analysis. The conduction mechanism was verified reasonably well by using scanning electron microscope (SEM) and UV-visible absorption data.     

Studies on the preparation and properties of conductive polymers. VIII. Use of heat treatment to prepare metallized films from silver chelate of PVA and PAN

Metallized polymer films were prepared from polyacrylonitrile or poly(vinyl alcohol) silver chelate solution by heat treatment. These metallized film exhibited low surface resistivity around 10⁰Ω/cm². The surface of these conductive films was proved to be metallized using X-ray analysis. The metal adhered on the film was believed to be responsible for the improvement of electrical conductivity. The effects of types and concentrations of silver salt, types and volume of solvent, and drying time on the conductivity of metallized films were investigated. © 1995 John Wiley & Sons, Inc.     

Studies on the preparation and properties of conductive polymers. X. Using metal plates to prepare metallized conductive polymer films

In this article, polymer metal chelate solutions were prepared by metal salts mixed with the polymers containing functional groups such as poly(vinyl alcohol) (PVA), polyacry-lonitrile (PAN), and polyurethane (PU). These polymer metal chelate solutions were cast on to metal plates, whose oxidation potentials were greater than those of the metal of polymer metal chelate solutions. After heat treatment, the metal ions in the polymer films were reduced to metal on the surface, therefore metallized conductive polymer films were obtained. © 1996 John Wiley & Sons, Inc.     

Studies on the electromagnetic interference shielding effectiveness of metallized PVAc‐AgNO3/PET conductive films

A metal chelate polymer (MCP) of PVAc‐AgNO₃ was prepared by adding AgNO₃ salts into the PVAc matrix and was coated on to PET substrate to form PVAc‐AgNO₃/PET films. These films were then treated with NaBH₄ aqueous solution to become the reduced metallized conductive films (RMCF) of PVAc‐AgNO₃/PET. The electromagnetic interference shielding effectiveness (EMI/SE) and the characteristics of these films were investigated. The SE value was measured by the far‐field transmission line method. The surface resistivity (Rs) of RMCF with a AgNO₃ content of 15 wt % was found to be below 5 Ω/sq, and the SE value exceeded 20 dB over the frequency range 50–900 MHz. The Rs of RMCF with a AgNO₃ content of 30 wt % was less than 1 Ω/sq, and the SE value even reached 33 dB at 550–650 MHz. It was confirmed by X‐ray and scanning electronmicroscope (SEM) analysis that the conducting network, as formed by closely deposited silver atoms on the reduced coating surface, was the dominant pathway for effective electron propagation that contributed to the excellent conductivity of these RMCF (PVAc‐AgNO₃/PET). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 270–273, 2004     

Aromatic polyamide–imides as materials for membranes. I. Synthesis and characterization

Diamine amic acids were synthesized by reacting aromatic diamines with pyromellitic dianhydride in dimethylacetamide/dioxane. High molecular weight polyamide-amic acids were prepared by low-temperature solution polymerization of diamine amic acids with isophthaloyl chloride in dimethylacetamide. The cyclodehydration of polyamide-amic acids to the corresponding polyamide–imides was accomplished by heating the cast films at 175°C for 3 h. The polyamide–imides were soluble in polar aprotic solvents like dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone and could be cast into tough and flexible films. They were characterized by elemental analyses, inherent viscosities, IR, and ¹H-NMR spectra. The glass transition temperatures of polyamide–imides were determined by differential scanning calorimetry. The thermal stabilities of the polymers were measured by thermogravimetric analyses in air. © 1995 John Wiley & Sons, Inc.     

Influence of metal salts in reaction medium on performance enhancement of novel aliphatic–aromatic-based polyamide thin-film composite osmosis membranes

In this study, we report an easy and novel way to develop high flux aliphatic–aromatic-based thin-film composite (TFC) polyamide osmosis membranes by addition of inorganic metal salts with amine reactants in the reaction system of polyethylene imine (PEI) and 1,3-benzene dicarbonyl chloride. Inorganic metal salts like CuSO₄, NiSO₄, MgSO₄, and Al₂(SO₄)₃ added to block some of the amine groups of PEI through complexation which in turn changes the polycondensation reaction kinetics of amine acid chloride reaction. The prepared membranes were characterized using water contact angle and atomic force microscopy studies and the performances were evaluated both in reverse osmosis and forward osmosis mode. In presence of metal salts in reaction interface, the performance of TFC membranes was greatly enhanced and the optimum metal salt concentration was identified for individual metal salts for maximum performance enhancement. The effects of different anions for same metal ion and different molecular weight of PEI were evaluated on composite polyamide membrane performances. Water permeability (flux) of 63.48 L m^?2 h^?1 was achieved upon inorganic salt addition compared to the unmodified TFC membranes with flux of 42.1 L m^?2 h^?1 at similar salt rejection of ~95%. Based on the new findings, a conceptual model was proposed to explain the role of metal ion in amine solution on the resulting characteristics of aromatic–aliphatic type polyamide–polysulfone composite membrane.     

Studies on the preparation and properties of conductive polymers. VII. Use of two-stage method to prepare Ag–Hg alloy on polymer films

Polymer metal chelate films were prepared by silver nitrate mixed with polymers containing functional groups such as poly(vinyl alcohol) (PVA) by using two-stage method to prepare Ag–Hg alloy on polymer films. In the first stage, polymer silver chelate was treated with doping agents. In the second stage, these treated films were further treated with Hg metal. After the two stage treatment, films with good electrical conductivity can be obtained. © 1994 John Wiley & Sons, Inc.     

高分子导电薄膜的制备与性能研究

采用溶胶-凝胶法用不同比例的铁钻盐与助络合剂混合制备了铁钴盐复合膜。以硼氢化钠水溶液还原尼龙6金属盐络合膜，可得到新的导电性能较好的高分子表面金属化材料，研究了还原条件，金属盐不同配比对膜材料导电性能的影响。     

Studies on the preparation and properties of conductive polymers. XI. Metallized polymer films by plating out

Metallized films were prepared from the plating‐out method. Various metal powders with lower reduction potential were dispersed in poly(vinyl alcohol) (PVA) aqueous solution dried to form a film, then treated with metal salt solutions having metal ions in the metal salt with higher reduction potential. Metallized PVA films exhibited low surface resistivity around 10⁰–10¹ Ω/cm² when using the plating‐out method. The surfaces of these films were shown to be metallized by means of X‐ray analysis. Scanning electron microscopy (SEM) was also studied. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1361–1365, 1999     

Crosslinkable polyamide–imides

A series of polyamide–imides were prepared from aromatic diamines and substituted isophthaloyl chlorides containing unsaturated imide rings. Aromatic polyamides from isophthaloyl chloride were also prepared for comparison. The polyamide-imides gave enhanced solubility compared to the aromatic polyamides and there was no deterioration in thermal stability or T_g. The PAIs were crosslinked by heating at 280°C/4 h under nitrogen. After this heat treatment all the PAIs became insoluble and their mechanical properties increased substantially; their thermal behavior, as measured by DSC and TGA, changed as a function of their chemical structure.     

Design,synthesis and characterization of novel electroactive polyamide with amine‐capped aniline pentamer in the main chain via oxidative coupling polymerization

By oxidative coupling polymerization of the macromonomer of oligoaniline and p‐phenylenediamine we have prepared a novel electroactive polyamide, exhibiting well‐defined molecular structure, interesting spectroscopic and electrochemical properties. The well‐defined molecular structure of the electroactive polyamide was confirmed by FTIR, NMR spectroscopy, elemental analysis and X‐ray powder diffraction (XRD) and the resulting polyamide exhibit an enhanced solubility in most of the organic solvents as compared with polyaniline. The UV–Vis spectra were used to monitor the chemical oxidation process of the reduced polyamide. Electrochemical activity of the polyamide was tested in 1.0M H₂SO₄ aqueous solution and it shows three redox peaks, which is different from the polyaniline. Moreover, the thermal properties of the polyamide were evaluated by thermogravimetric analysis (TGA) and it shows moderate thermal resistance in the N₂ atmosphere. Its electrical conductivity is about 1.04 × 10^?4 S cm^?1 at room temperature upon preliminarily protonic‐doped experiment. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1603–1608, 2007     

Study properties of nanocomposites prepared with new polyimides and reactive nanosilica by epoxide functionalization

In this article, new types of organosoluble polyimides, poly(carbazole‐quinoxaline‐imide)s (PCQI), were synthesized and used in preparation of nanocomposites with modified nanosilica (mNS). The synthesized polyimides bearing different solubilizing functional moieties were casted into thin films at room temperature. SiO₂ nanoparticles were surface modified with γ‐glycidoxypropyltriethoxysilane (GPTES) to obtain mNS containing epoxide functional groups. The PCQI/mNS nanocomposites were prepared via cure reaction of epoxide groups and polymer functional units. The PCQIs and nanocomposites films were tested for different properties including thermal using TGA and DMTA, mechanical, thermomechanical, photophysical, solubility, water uptake, and metal ions adsorption. The strong chemical bonding between mNS particles and polymer matrix reduced solubility of nanocomposite and enhanced thermal stability in term of 10% weight loss temperature (T_10%, from 509°C to 582°C) and tensile strength (from 110 MPa to 155 MPa). These polyimides and nanocomposites were also efficient chelating agents for removal of metal ions such as , Cr³⁺, Pb²⁺, Cd²⁺, and Hg²⁺ from aqueous solutions either individually or in the mixture and at different pH values. POLYM. COMPOS. 36:545–555, 2015. © 2014 Society of Plastics Engineers     

Permeabilität galvanisch beschichteter Polymerfolien. I. Methode zur Messung der Gaspermeabilität

The construction and function of an apparatus for the determination of gas permeability through metallized polymer films is described. The test gases N₂, O₂, and CO₂ penetrate under pressure differences from 100 torr to 20 bar through galvanized ABS films (acrylonitrile–butadiene–styrene copolymer). The metallic layers consists of chemically deposited Ni and a galvanic deposited Cu having a thickness of 2–30 μm. The quantity of permeated gases is determined by gas chromatography. The lowest permeability coefficient obtained is 10^?17 (cm³ cm/cm² sec torr). Leak effects can be measured quantitatively. The permeability of gas mixtures (i.e., air) can also be investigated. The apparatus allows the determination of extremely low permeability rates as well as those for conventional polymer systems.     

Sulfobetaine polyurethane ionomers. Salts effects of the properties of dilute solutions and polymer films

The viscosimetric behaviour of diluted DMF solutions of some sulfobetaine polyurethanes and also the influence of some mono- and bivalent metal salts were studied. The study showed that polyurethane zwitterionomers behave as polyelectrolytes. Films of these polymers complexed with bivalent metals can form, in situ, particles of metal sulfides by exposure to slow H₂S flow. Preliminary results show an increased conductivity of films treated with H₂S, suggesting a microphase segregation structure.     

Synthesis and properties of poly(amide–imide)s based on N,N′‐bis(4‐carboxyphenyl)‐4,4′‐oxydiphthalimide,p‐aminobenzoic acid and various aromatic diamines

A new diimide–diacid monomer, N,N′‐bis(4‐carboxyphenyl)‐4,4′‐oxydiphthalimide (I), was prepared by azeotropic condensation of 4,4′‐oxydiphthalic anhydride (ODPA) and p‐aminobenzoic acid (p‐ABA) at a 1:2 molar ratio in a polar solvent mixed with toluene. A series of poly(amide–imide)s (PAI, III_a–m) was synthesized from the diimide–diacid I (or I′, diacid chloride of I) and various aromatic diamines by direct polycondensation (or low temperature polycondensation) using triphenyl phosphite and pyridine as condensing agents. It was found that only III_k–m having a meta‐structure at two terminals of the diamine could afford good quality, creasable films by solution‐casting; other PAIs III using diamine with para‐linkage at terminals were insoluble and crystalline; though III_g–i contained the soluble group of the diamine moieties, their solvent‐cast films were brittle. In order to improve their to solubility and film quality, copoly(amide–imide)s (Co‐PAIs) based on I and mixtures of p‐ABA and aromatic diamines were synthesized. When on equimolar of p‐ABA (m = 1) was mixed, most of Co‐PAIs IV had improved solubility and high inherent viscosities in the range 0.9–1.5 dl g^?1; however, their films were still brittle. With m = 3, series V was obtained, and all members exhibited high toughness. The solubility, film‐forming ability, crystallinity, and thermal properties of the resultant poly(amide–imide)s were investigated. © 2002 Society of Chemical Industry     

Thermal conductivity of yttria-stabilized zirconia thin films grown by plasma-enhanced atomic layer deposition

Zirconia doped with yttrium, widely known as yttria-stabilized zirconia (YSZ), has found recent applications in advanced electronic and energy devices, particularly when deposited in thin film form by atomic layer deposition (ALD). Although ample studies reported the thermal conductivity of YSZ films and coatings, these data were typically limited to Y₂O₃ concentrations around 8 mol% and thicknesses greater than 1 μm, which were primarily targeted for thermal barrier coating applications. Here, we present the first experimental report of the thermal conductivity of YSZ thin films (∼50 nm), deposited by plasma-enhanced ALD (PEALD), with variable Y₂O₃ content (0–36.9 mol%). Time-domain thermoreflectance measures the effective thermal conductivity of the film and its interfaces, independently confirmed with frequency-domain thermoreflectance. The effective thermal conductivity decreases from 1.85 to 1.22 W m⁻¹ K⁻¹ with increasing Y₂O₃ doping concentration from 0 to 7.7 mol%, predominantly due to increased phonon scattering by oxygen vacancies, and exhibits relatively weak concentration dependence above 7.7 mol%. The effective thermal conductivities of our PEALD YSZ films are higher by ∼15%–128% than those reported previously for thermal ALD YSZ films with similar composition. We attribute this to the relatively larger grain sizes (∼23–27 nm) of our films.     

A DFT Survey of the Effects of d-Electron Count and Metal Identity on the Activation and Functionalization of C−H Bonds for Mid to Late Transition Metals

The contribution of metal identity to the activation and functionalization of methane by a series of three-coordinate imide complexes is evaluated in silico for a 3-by-3 block of metals from Fe to Pt. Three mechanisms were studied: oxidative addition (OA) to the metal; hydrogen atom abstraction (HAA) by the imide nitrogen; and, [2+2] addition across the metal-imide bond. In no studied case, was a [2+2] mechanism preferred, perhaps suggesting this mechanism is largely (entirely?) the domain of d⁰ imides. There is a diagonal relationship within the nonet of metals studied in that OA is preferred for earlier, heavier (5d) members of the series, transitioning to an HAA mechanism for later, lighter (3d) imides. DFT indicates that important parameters in partitioning between HAA and OA mechanisms include the strength of the metal-imide π-bond, the ability of larger metals to accommodate increases in formal oxidation state and coordination number, and the soft acid/base compatibility of larger transition metals with soft hydride and methyl ligands     

Studies on the synthesis and properties of soluble homo- and copolyester–imide derived from imide–diacid

A series of polyester–imides was prepared from diacid (imid–diacid [ M1–M4 ] or a mixture of imide–diacid and terephthalic acid [TPA]) and bisphenol A in the presence of diphenyl chlorophosphate (DPCP) and pyridine as a direct condensation agent. The inherent viscosites of homo- and copolyester–imides were in the range of 0.39–0.58 dL/g. Almost all these homo- and copolyester–imides were completely soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAC), dimethylformamide (DMF), and m-cresol. The thermal properties of homo- and copolyester–imides were examined by DSC and TGA. These copolyester–imides had glass transition temperatures in the range of 95–240°C and a 5% weight loss was observed in the range of 354–465°C. © 1995 John Wiley & Sons, Inc.