Surface structure and properties of water‐based polymer coating materials prepared by the complexation of two polymer latices with chemically complementary structures

In this study, water‐based polymer coating materials used for the surface coating of substrates with lower surface energies were prepared by the complexation of two‐component polymer latices containing polydimethylsiloxane (PDMS) and having chemically complementary structures. The film‐forming performance of the polymer latices and the surface structures and properties of the coatings formed by the polymer latices were studied by means of scanning electron microscopy and by the measurement of mechanical strength, thermal performance, water absorbability, and contact angle. When the two‐component polymer latices [the poly(methyl methacrylate‐co‐butyl acrylate‐co‐methyl acrylic acid)/polydimethylsiloxane system (PA latex) and the poly(methyl methacrylate‐co‐butyl acrylate‐co‐pyrrolidone)/polydimethylsiloxane system (PB latex)] were compared, the complex polymer latex formed by the complexation of the PA latex with the PB latex had the best film‐forming performance, with formed coatings that were more smooth and had fewer less cracks. Also, compared to the two coatings formed by the two‐component polymer latices, the coatings formed by the complex polymer latex had a unique structure, a higher mechanical strength and elongation, a higher decomposing temperature, and better water resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1748–1754, 2003     

Thin polymer films from fluidized electrode bed reactors

The formation and deposition of a polymer as a thin, uniform solid film on a metal particle substrate is investigated in detail in a fluidized electrode bed reactor. Experiments were carried out in different designs of fluidized bed electrode cell reactor, using various metal particles and monomers. It was observed that diacetone acrylamide (DAA) monomer in 0.1N H₂SO₄ with aluminum particles (3530 μm) as cathode, in a concentric dual compartment cell, appeared to yield the best films. Infrared and elemental analyses were used to characterize the polymer film on the metal particles. Scanning electron microscopy (SEM) was employed to examine the surface and cross-sectional profiles of the films. The potential profiles in both particulate and solution phases were measured and the importance of particulate electrical conductivity in the polymerization is thus explained. It was observed that the optimum particulate conductivity and hence the maximum yield occurs in the range of 10–20% bed expansion. The experimental product yields for various liquid superficial velocities (i.e., bed expansion) at different feeder current densities were compared to explain the possible controlling mechanism in packed and fluidized bed cells, noting that both chemical reaction and mass transfer control in the low bed expansion region while chemical reaction controls in the high bed expansion region. The current effciency decreases in the high current region due to side reactions at the fluidized bed electrode and due to pore diffusion in the polymer film.     

Effect of acrylonitrile content of styrene-co-acrylonitrile (SAN) on morphology and electrooptical properties of polymer/liquid crystal composite films

Effects of copolymer composition on morphology and electrooptical properties of polymer/liquid crystal (LC) (40/60 w/w) composite films were studied with styrene-co-acrylonitrile (SAN) of varying acrylonitrile (AN) content (6.3–35 wt %) and a cyanobiphenyl-type liquid crystal (E8). The dimension of the LC domain in the composite film decreased with increase of AN content of SAN up to 30 and increased at 35 wt %. The contact angle of the film with an LC drop showed a similar trend; however, its minimum was obtained at 24% AN. Threshold voltage (V_th) and rise time (τ_R) increased, and decay time (τ_D) decreased with AN content up to 30%, and the tendency is reversed at 35%. The results were interpreted in terms of, possibly, a solubility parameter matching between SAN and LC. © 1993 John Wiley & Sons, Inc.     

Electrochemically initiated (co)polymerization of acrylamide and acrylonitrile on a steel cathode—electrochemical and impedance study

Investigations were carried out into the processes of electrochemically initiated (co)polymerization (EIP) of acrylamide (AA) and/or acrylonitrile (AN) from acidic aqueous solutions on a steel cathode. The aim was to obtain (co)polymer films with given electroinsulating and corrosion protection properties. The kinetics of (co)polymer film formation were investigated using various electrochemical methods (constant current and constant potential electrolysis, cyclic voltammetry, double-layer capacity measurements) and ellipsometry. The electrical properties of the films formed were studied (ex situ) by measuring their impedance (Z) and phase angle () as a function of frequency. It was shown that equivalent circuit (EC), proposed for covered metal surfaces in solutions, can be satis-factorily applied. The values of the EC elements obtained by curve fitting to experimental results show the influence of the thermal treatments and/or moisture concentration on the impedance characteristics of polymer films. The mechanism of (co)polymer film formation as well as the electrical and corrosion protection properties are discussed with regard to the experimental parameters and some characteristics of the films obtained.     

Improvement in the adhesion between copper metal and polyimide substrate by plasma polymer deposition of cyano compounds onto polyimide

The surface modification of Kapton film by means of plasma polymer deposition is discussed from the viewpoint of improving the adhesion between copper metal and Kapton film substrate. Plasma polymers of AN (acrylonitrile) and FN (fumaronitrile) were used for the surface modification, and the adhesion between the copper metal and the plasma polymer-coated Kapton film was evaluated by the T-peel strength measurement. The surfaces of peeled layers were analyzed by X-ray photoelectron spectroscopy (XPS) and the failure mode is discussed. The plasma polymer deposition of AN and FN shows an effective improvement in the adhesion between the copper metal and Kapton film; in particular, the AN plasma polymer deposition increased the peel strength 4.3 times. Failure occurred mainly in the Kapton film, and the adhesion between the AN plasma polymer and the Kapton film and that between the copper metal and the AN plasma polymer were found to be quite strong.     

Enhancement of the electrical properties of poly(p‐phenylene vinylene) by the incorporation of silicon dioxide nanoparticles

The electrical properties of a poly(p‐phenylene vinylene) (PPV) conjugated polymer using silver (Ag) as a cathode were improved by the incorporation of silicon dioxide (SiO₂) nanoparticles. The current density of the Ag–PPV/SiO₂ nanocomposite system was higher than that of Ag–PPV. A lower level of interfacial oxidation was found in the Ag–PPV/SiO₂ nanocomposite than in Ag–PPV, confirming that a more complete elimination of residue occurred in the nanocomposite. This was due to the relatively large surface area of the PPV/SiO₂ nanocomposite film and the hydrophilic surface of the SiO₂ nanoparticles. The lower level of oxidation contributed to an improvement in the material's current–voltage characteristics. Morphology‐dependent current–voltage characteristics were enhanced by a large variation in the thickness of the Ag–PPV/SiO₂ nanocomposite film because an increased effective field strength could be induced in the thinner regions of the film. The incorporation of SiO₂ nanoparticles altered the effective film thickness and the amount of residue in the interior of the PPV without disrupting the structure of the conjugated polymer. The Ag cathode created a stable interface with the PPV film layer without causing the formation of an organic–metal complex, which would have obstructed electron injection. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Surface modification of coil coatings with thin plasma polymer films structure and stability

Plasma deposition of a thin top layer with tailored properties is an effective strategy of modification of the organic coating surface. Thin plasma polymer layers are candidates and can provide superior hardness, scratch resistance, modified surface hydrophobicity and easy to clean properties.The present work studies the stability of thin plasma polymer films deposited as top layer on polyurethane coil coating systems. Microwave, hollow cathode and radio frequency plasma polymerization reactors were employed in order to deposit a thin SiO_x based plasma polymer layer.The plasma film stability was studied using surface analysis techniques, ex situ and in situ atomic force microscopy and scanning electron microscopy. Energy dispersive spectroscopy, FTIR spectroscopy and optical measurements confirm the composition and plasma layer properties. The structure of the plasma layers was investigated by means of transmission electron microscopy.The surface morphology together with composition evolution allows the study of the stability of the different coatings. The structure examination of the formed plasma polymer film offers good clarification for coating failure. Decrease of the operating pressure during plasma polymerization and oxygen concentration in precursor mixture lead to formation of compacter layer with higher stability. Introduction of fluorine-containing precursor also increases the anti-weathering performance of the plasma polymer films.     

Synthesis and characterization of poly(urethane‐ether)s from calcium salt of p‐hydroxybenzoic acid

The synthesis and characterization of calcium‐containing poly(urethane‐ether)s, having ionic links in the main chain, is reported. Calcium salt of p‐hydroxybenzoic acid (HBA‐Ca) was prepared from p‐hydroxybenzoic acid (HBA) and used as the chain extender in the preparation of calcium‐containing poly(urethane‐ether)s. Poly(urethane‐ether)s, having two different compositions, were prepared by varying the mole ratios of poly(tetramethylene glycol), hexamethylene diisocyanate, and HBA‐Ca. The synthesized poly(urethane‐ether)s were characterized by infrared spectroscopy, thermogravimetric analysis, and dynamic mechanical analysis. The presence of calcium in the polymer chain was confirmed by energy‐dispersive X‐ray analysis. The inherent viscosity of metal‐containing polymers decreased with the increase in the metal content of the polymer. The introduction of metal into the polymer lowers the thermal stability of the polymers as indicated by the decreased initial decomposition temperature. The glass transition temperature (T_g) and the storage modulus of the metal‐containing polymers increase with the increase in metal content presumably due to the formation of physical crosslink's in the polymer. From the mechanical studies of the polymer, it was observed that the metal‐containing polymers exhibit high tensile strength and modulus. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Voltammetric investigations on the transition between dissolution, passivation and deposition characteristics of Ni, Cu and their alloys in fluorine based ionic liquid

Multisweep cyclic voltammetric (CV) responses of nickel, copper, Monel and nickel–copper alloy had been extensively studied and compared in a variety of non-aqueous solvents such as acetonitrile (AN), propylene carbonate (PC) and sulfolane containing triethylamine trishydrogen fluoride (TEA·3HF) ionic liquid. The quantity of dissolution as well as surface morphological transformation on the electrode surfaces as a result of anodic polarization were investigated using atomic absorption spectroscopy (AAS) and scanning electron microscopy (SEM) respectively. The nature of crystallites formed on the polarized electrode was characterized using X-ray diffraction (XRD). The voltammetric study clearly indicates that Ni, Monel and Ni–Cu alloy are passive and stable in neat TEA·3HF medium in the recorded potential region of CV. Surface morphology of Ni after polarization, reveals the generation of pits, whereas the evolution of small crystallites of CuF₂ are noted on the polarized alloy material, as evidenced by SEM pictures. Copper electrode shows reversible voltammetric characteristics with high charge recovery ratio (q_c/q_a) suggesting that in this medium, Cu can certainly serve as reference electrode. Addition of water in TEA·3HF medium increases the solubility and stability of these metal fluoride film. In solvents such as PC, AN and sulfolane containing TEA·3HF, Ni and their alloys exhibit remarkable passivity and the charge recovery ratio decreases to some extent for Cu. In TEA·3HF/AN medium, the dissolution of Cu is very high. The present investigation suggests that the relative stability of all the four electrodes in neat TEA·3HF and solvents containing 0.1 M TEA·3HF decreases in the order: Ni > Monel > Ni–Cu alloy > Cu and relative solubility of metal fluoride films in the three solvents increases in the order: PC < sulfolane < AN.     

Gas permeation of polymer blends. II. Poly(vinyl chloride)/acrylonitrile–butadiene copolymer (NBR) blends

The transport behavior of He, O₂, N₂, and CO₂ in a series of PVC/NBR polymer blends with varying acrylonitrile (AN) content in the NBR component has been studied at 25° and 50°C. In addition, measurements of density, crystallinity, and thermal expansion coefficients were carried out. The transport behavior of these blends is similar to previous result for PVC/EVA.¹. With increasing AN content in NBR, the permeability (P) and diffusivity (D) of the permeants decreased while the activation energy for diffusion (E_D) increased. For the polymer blends, better additivity of permeability and diffusivity was observed with increasing AN content in the NBR component. The polymer blends also showed increasing volume contraction with increasing AN content in the NBR component. These effects have been discussed as due mainly to increased polymer–polymer interaction causing reduced segmental mobility and increased compatibility of the two polymers. The sorption values calculated from P/D ratios were largely irregular and fluctuated with the blend composition. They were less reproducible than other transport parameters, i.e., P and D measured separately. Several reasons for the irregular sorption behavior were proposed.     

Electrochemical preparation and characterization of nickel and zinc-modified poly-2-aminothiazole films on mild steel surface and their corrosion inhibition performance

Poly-2-aminothiazole (pAT) was electrochemically synthesized on a mild steel (MS) specimen from 0.3 M aqueous ammonium oxalate solution containing 0.01 M 2-aminothiazole (2-AT) using cyclic voltammetry technique. The synthesized polymer film was then modified by electrodeposition of 100 μg cm⁻² Ni (MS/pAT–Ni) and Zn (MS/pAT–Zn) on top of the polymer surface. The surface morphologies of the polymer films were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The elemental analysis of the surface films was performed by energy dispersive X-ray spectroscopy (EDX). The effectiveness of the coatings in preventing corrosion of MS in 3.5% NaCl solution was assessed using electrochemical techniques. It was found that the obtained coatings were adherent to the steel surface. The pAT film provided a good corrosion protection against the attack of corrosive environment. Moreover, the modification of pAT film by deposition of Ni and Zn on top of the polymer surface significantly enhances the corrosion protection performance of the polymer film by exhibiting an improved barrier effect against the attack of corrosive environment. The surface morphologies and protection ability of the layers were found to be dependent on the type of deposited metal.     

Surface tailoring of an ethylene propylene diene elastomeric terpolymer via plasma‐polymerized coating of tetramethyldisiloxane

In the research presented here, we explore the use of a low‐energy plasma to deposit thin silicone polymer films using tetramethyldisiloxane (TMDSO) (H(CH₃)₂? Si? O? Si? (CH₃)₂H) on the surface of an ethylene propylene diene elastomeric terpolymer (EPDM) in order to enhance the surface hydrophobicity, lower the surface energy and improve the degradation/wear characteristics. The processing conditions were varied over a wide range of treatment times and discharge powers to control the physical characteristics, thickness, morphology and chemical structure of the plasma polymer films. Scanning electron microscopy (SEM) shows that pore‐free homogeneous plasma polymer thin films of granular microstructure composed of small grains are formed and that the morphology of the granular structure depends on the plasma processing conditions, such as plasma power and time of deposition. The thicknesses of the coatings were determined using SEM, which confirmed that the thicknesses of the deposited plasma‐polymer films could be precisely controlled by the plasma parameters. The kinetics of plasma‐polymer film deposition were also evaluated. Contact angle measurements of different solvent droplets on the coatings were used to calculate the surface energies of the coatings. These coatings appeared to be hydrophobic and had low surface energies. X‐ray photoelectron spectroscopy (XPS) and photoacoustic Fourier‐transform infrared (PA‐FT‐IR) spectroscopy were used to investigate the detailed chemical structures of the deposited films. The optimum plasma processing conditions to achieve the desired thin plasma polymer coatings are discussed in the light of the chemistry that takes place at the interfaces. Copyright © 2004 Society of Chemical Industry     

Oxygen barrier property of synthesized polyacrylate coatings containing inter-chain cross-linking architecture on PET film

A series of coatings which applied for improving the oxygen barrier property of polyethylene terephthalate (PET) film were prepared based on the copolymerization of methyl methacrylate, methyl acrylate, diallyl maleate, and maleic acid (MA). The chemical structures of the coatings were characterized by Fourier Transform Infrared spectrometer. The curing behavior was analyzed by differential scanning calorimetry. The oxygen permeability (Po₂) was measured by gas permeability tester . The molecular weight was investigated by gel permeation chromatography (GPC). Po₂ is inversely proportional to the oxygen barrier property that the decrease of Po₂ indicates the improvement of oxygen barrier property. The coating containing inter-chain cross-linking structure formed by the dehydration of carboxylic acid improves the oxygen barrier property of PET film greatly. With the increasing content of MA, the oxygen barrier capability of coated PET film is enhanced according to the Po₂ decreasing from 1.450 to 0.8956. The Po₂ of coated PET film is minimized by selecting N-methyl pyrrolidone as solvent for polymerization. The GPC results indicate that the oxygen barrier of novel coated PET film can be obtained when the weight average molecular weight (Mw) is up to the stipulated value.     

Synthesis of nano polyaniline and poly-<Emphasis Type="Italic">o</Emphasis>-anisidine and applications in alkyd paint formulation to enhance the corrosion resistivity of mild steel

Protection of oxidizable metals against corrosion has now being intensively investigated, by applying or developing different methods such as coatings and conversion films; however, all reported methods involve environmentally hazardous materials. Conducting polymers have now been used as corrosion inhibitor coatings that are either chemically or electrochemically deposited on the metal substrate. The application of nanotechnology in the corrosion protection of metals has recently gained momentum. Environmental impact can also be improved by utilizing nanostructure particulates in coatings and eliminating the requirement of toxic solvents. We report here the synthesis of nanoparticles of polyaniline (PANI) and poly-o-anisidine (POA) using emulsion polymerization method in micellar solution of SDS and their anticorrosive property has been experimentally checked. The prepared nanoparticles have been characterized by FTIR and TEM. The nanoparticles of the synthesized polymers were dispersed in alkyd paint formulation for coatings on the metal surface (mild steel). The water absorption in the prepared coatings was also studied. The corrosion rate of polymeric film was determined by weight loss measurement and the surface morphology was examined by SEM. The nano PANI/Alkyd coatings showed considerable protection against corrosion than the POA/alkyd coatings.     

Synthesis and properties of poly(acrylonitrile‐co‐p‐trimethylsilylstyrene) and poly(acrylonitrile‐co‐p‐trimethylsilylstyrene‐co‐styrene)

Copolymerization of acrylonitrile (AN) with p‐trimethylsilylstyrene (TMSS) was carried out at 60°C in bulk and in solution in the presence of 2,2′‐azobisisobutyronitrile (AIBN). The reactivity ratios of AN (M₁) and TMSS (M₂) were determined to be r₁ = 0.068 and r₂ = 0.309. The effects of the AIBN concentration and that of the chain transfer agent CCl₄ on the molecular weights (MWs) of the copolymers were investigated. An increase in the concentrations of AIBN or CCl₄ in solution led to a decrease in MW. Poly(AN‐co‐TMSS‐co‐St) was synthesized in solution using AIBN as the initiator. The molar fraction of AN was 0.415, while the molar ratio of TMSS/St varied from 1 : 1 to 1 : 9. The transition temperatures and thermal and thermooxidative stabilities of poly(AN‐co‐TMSS) and poly(AN‐co‐TMSS‐co‐St) were investigated. The differential scanning calorimeter technique was used to determine the compatibility of the poly(AN‐co‐TMSS) and poly(AN‐co‐TMSS‐co‐St) with commercial poly(AN‐co‐St). All the blends show a single glass transition temperature, which indicates the compatibility of the blend components. The surface film morphology of the blends mentioned above was examined by X‐ray photoelectron spectroscopy. The data obtained indicate that the silicon‐containing copolymer is concentrated in the surface layer. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1920–1928, 2000     

In-situ generation and application of nanocomposites on steel surface for anti-corrosion coating

Thin organic coatings directly on steel sheets provide excellent barrier protection in saline environment and meet deformability demands, but fail in providing active corrosion protection. We have put an effort to solve this problem by formulating composite coatings using in-situ generation of metal oxide nanoparticles (NPs) in the polymer matrix. Here we present a new synthesis method of high performance polyetherimide composite with TiO₂, MgO, and Al₂O₃ nanoparticles and their application for anti-corrosion coatings in saline environment. We observed that in-situ synthesis of these metal oxide NPs in the polymer curing process leads to evenly distribution and uniform size of nanoparticles. Thermo-mechanical property was analyzed for these three kinds of free-standing composite film to assess elasto-plastic behaviour and compared to mother polymer film. Results indicated that thermal stability and elastic behaviour of composites film are not affected to the great extent by the presence of NPs. The potentiodynamic and the electrochemical impedance studies on these composite coated steel panels were carried out to identify active–passive behaviour. Results showed active corrosion protection from nanocomposite coating based on TiO₂ and barrier protection was noticed from nanocomposite coating based on MgO and Al₂O₃.     

Thermodynamic Control of Phase Composition and Crystallization of Metal‐Modified Silicon Oxycarbides

Silicon oxycarbides modified with main group or transition metals (SiMOC) are usually synthesized via pyrolysis of sol‐gel precursors from suitable metal‐modified orthosilicates or polysiloxanes. In this study, the phase composition of different SiMOC systems (M = Sn, Fe, Mn, V, and Lu) was investigated. Depending on the metal, different ceramic phases formed. For M = Mn and Lu, MO_x/SiOC ceramic nanocomposites were formed, whereas other compositions revealed the formation of M/SiOC (M = Sn), MSi_x/SiOC (M = Fe) or MC_x/SiOC (M = V) upon pyrolysis. The different phase compositions of the SiMOC materials are rationalized by a simple thermodynamic approach which generally correctly predicts which type of ceramic nanocomposite is expected upon ceramization of the metal‐modified precursors. Calculations show that the thermodynamic stability of the MO_x phase with respect to that of the C–O system is the most important factor to predict phase formation in polymer‐derived SiMOC ceramic systems. A secondary factor is the relative stability of metal oxides, silicates, carbides, and silicides.     

Moisture absorption into ultrathin hydrophilic polymer films on different substrate surfaces

Moisture absorption into ultrathin poly(vinyl pyrrolidone) (PVP) films with varying thickness was examined using X-ray reflectivity (XR) and quartz crystal microbalance (QCM) measurements. Two different surfaces were used for the substrate: a hydrophilic silicon oxide (SiO_x) and a hydrophobic hexamethyldisilazane (HMDS) treated silicon oxide surface. The total equilibrium moisture absorption (solubility) was insensitive to the surface treatment in the thickest films (≈150 nm). However, strong reductions in the equilibrium uptake with decreasing PVP film thickness were observed on the HMDS surfaces, while the SiO_x surface exhibited thickness independent equilibrium absorption. The decreased absorption with decreasing film thickness is attributed a depletion layer of water near the polymer/HMDS interface, arising from hydrophobic interactions between the surface and water. The diffusivity of water decreased when the film thickness was less than 60 nm, independent of the surface treatment. Changes in the properties of ultrathin polymer films occur even in plasticized films containing nearly 50% water.     

Electrochemical formation and characterization of porous titania (TiO2) films on Ti

Galvanostatically and potentiostatically formed surface oxide films on titanium in H₂O₂ free and H₂O₂ containing H₂SO₄ solutions were investigated. Conventional electrochemical techniques, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy, were used. In the absence of H₂O₂, the impedance response indicated a stable thin oxide film which depends on the mode of anodization of the metal. However, in the presence of H₂O₂ the film characteristics were changed. A significant decrease in the corrosion resistance of the surface film was recorded. The film characteristics were also found to be affected by the mode of oxide film growth and polarization time. The EIS results and the impedance data fitting to equivalent circuit models have shown that the oxide film consists of two layers. The electrochemical characteristics of the anodic films formed under different conditions have been discussed.     

Electropolymerization of monomers on metal electrodes

The use of electropolymerization to coat metal electrode surfaces with polymers formed in situ was investigated in detail. Electrolysis was carried out in a three-compartment cell with fritted disk separators such that polymerization occurred in the middle compartment only. Both anodic and cathodic reactions were utilized to form coating on pretreated metal surfaces. It was shown that polymerization occurred both by vinyl polymerization of olefin monomers as well as by ring-opening reactions of cyclic monomers. The factors that control the coating thickness, the morphology of the polymer deposit, and the adhesion of the polymer formed to the metal substrates were determined. It was found that the growth of the coating on electrode followed the chain polymerization kinetics to a considerable degree. However, increased current did not necessarily lead to increased coating thickness because it also led to increased early termination of growing polymer chains to form soluble low molecular weight products. Water, because of its high surface tension, encourages physical adsorption on metal surfaces of organic monomers dissolved in it. Thus, water was found to be unique as solvent for obtaining coatings with good adhesion to metal substrates. Coatings formed were analyzed by several methods including infrared spectroscopy. Several types of bonding, other than bond formation caused by polymerization reactions, were identified. Finally, the cyclization of polyacrylonitrile was observed when the coating was obtained on aluminum cathode during electrolysis of acrylonitrile–sodium nitrate–DMF solution.