Acid−base properties of polyethylene composites with clays

We report on the surface energy characteristics of composite materials based on low‐density polyethylene with addition of bentonite and organic clay. Investigated were the surface free energy, its components and parameters by wetting methods according to Berger, spatial method, and method of nonlinear systems. The determined characteristics were carried out by the selective wetting conditions for the individual constituents of the composition, including the clay powder. The thermal, mechanical, and morphological properties of obtained composites were investigated. The possibility for predicting the surface properties of composite materials based on component‐wise analysis was demonstrated. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43629.     

Acid–base surface properties of modified poly(ethylene terephthalate) films and gelatin: Relationship to adhesion

Characterization of poly(ethylene terephthalate) (PET) films surfaces through wettability measurements and inverse gas chromatography techniques leads to a better knowledge of the potential interactions with a coating. An important case is the one relative to gelatin coatings for photographic films. In order to favor adhesion on PET, it is of interest to examine the problem in terms of acid–base interactions. PET is found amphoteric and gelatin rather basic. Several surface treatments on PET like orientation on water and flame or plasma treatment in air lead to an increase in surface acidity. Adhesion with gelatin as determined by the peel test is increased through a flame treatment, because of the higher acidity of PET and subsequent chemical bonding at the interface. Determination of acid-base surface properties of PET and gelatin appears to be an excellent tool for adhesion prediction.     

Acid–base behavior of an oligomer of 3‐amino‐1,2,4‐triazole

We report the acid–base behavior of OATA, an oligomer synthesized from 3‐amino‐1,2,4‐triazole (ATA). We analyze the UV–vis spectroscopy at different media, and we analyze and discuss the acid–base equilibria taking into account tautomeric equilibria at different pH. The low aqueous solubility at neutral pH can be attributed to the neutral form. Indeed, OATA was synthesized in an ordinary filter paper, which can be used as a sensor for ammonia as well as endpoint indication. Using the OATA‐containing paper, ammonia concentrations in a solution as low as 5 ppm could be measured. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Moulding properties of a Nigerian silica–clay mixture for foundry use

The moulding properties of Igbokoda silica sand, bonded with Ijero–Ekiti clay, were investigated. American Foundrymen Society (AFS) standard cylindrical samples dimensioning Ø50 mm × 50 mm in height were prepared from various sand–clay ratios with 5% tempering water, by applying three ramming blows of 6.666 g each from a height of 50 mm as required for foundry sands. The samples were subjected to various physical and mechanical tests. These include permeability, green compression strength, and dry compression strength tests. Green shear strength, dry shear strength, field mould strength, shattered index and refractoriness tests were also carried out on the samples. Samples containing 23–32% clay were found to possess adequate permeability, good strength and refractoriness suitable for casting of both ferrous and non-ferrous alloys.     

Dyeing transition temperature of wools treated with low temperature plasma,liquid ammonia,and high‐pressure steam in dyeing with acid and disperse dyes

Wool fibers treated with oxygen low‐temperature plasma, liquid ammonia (NH₃), and high‐pressure (HP) steam were dyed with two acid and three disperse dyes. Rate of dyeing, saturation dye uptake, and dyeing transition temperature were measured. Rate of dyeing of the O₂ plasma, NH₃, and HP steam‐treated wools increased with acid dyes, whereas it did not increase with disperse dyes. Although dyeing transition temperature for acid dyes was decreased by the plasma, NH₃, and HP steam treatments, the temperature for disperse dyes was not changed by the treatments. Therefore, it seems that acid dyes penetrate by the intercellular diffusion through the interscale Cell Membrane Complex (CMC) of wool, whereas disperse dyes penetrate by the intracellular diffusion through the intrascale cuticle surface independently with CMC relaxation by the treatments. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1058–1062, 2001     

Differential dyeing cotton. 1 – Preparation and evaluation of differential dyeing cotton yarn

Colourless cationic and anionic cellulose-reactive compounds have been prepared and applied to cotton yarns. Yarn pretreated with cationic reagents shows better uptake of acid and direct dyes than does untreated yarn, and since the degree of differential uptake depends on the level of pretreatment, which may be readily controlled, fabrics exhibiting a variety of tone-on-tone effects may be produced. Treatment with an anionic reagent gives cotton dyeable with basic dyes, and combinations of anionic- and cationic-treated yarns may be cross-dyed in a single-bath, one-step process with very little cross-staining. Pretreated cotton may be converted to viscose or cellulose triacetate fibre with retention of the modified dyeing properties, thus providing routes to differential dyeing viscose and triacetate fibres. We wish to thank the British Technology Group for financial support of this work for the period 1983–86, and Mrs F A Wood for technical assistance.     

Effect of styrene–isoprene–styrene,styrene–butadiene–styrene,and styrene–butadiene–rubber on the mechanical,thermal, rheological,and morphological properties of polypropylene/polystyrene blends

The mechanical, thermal, rheological, and morphological properties of polypropylene (PP)/polystyrene (PS) blends compatibilized with styrene–isoprene–styrene (SIS), styrene–butadiene–styrene (SBS), and styrene–butadiene–rubber (SBR) were studied. The incompatible PP and PS phases were effectively dispersed by the addition of SIS, SBS, and SBR as compatibilizers. The PP/PS blends were mechanically evaluated in terms of the impact strength, ductility, and tensile yield stress to determine the influence of the compatibilizers on the performance properties of these materials. SIS‐ and SBS‐compatibilized blends showed significantly improved impact strength and ductility in comparison with SBR‐compatibilized blends over the entire range of compatibilizer concentrations. Differential scanning calorimetry indicated compatibility between the components upon the addition of SIS, SBS, and SBR by the appearance of shifts in the melt peak of PP toward the melting range of PS. The melt viscosity and storage modulus of the blends depended on the composition, type, and amount of compatibilizer. Scanning electron microscopy images confirmed the compatibility between the PP and PS components in the presence of SIS, SBS, and SBR by showing finer phase domains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 266–277, 2003     

Viscoelastic properties of polyaniline–emeraldine base nanostructured films: Experimental results and molecular dynamics simulations

Comprehensive exploration of the viscoelastic properties of polyaniline–emeraldine base (PANI–EB) nanostructured films is presented from two viewpoints of experimental study associated with dynamic mechanical thermal analysis and thermogravimetric measurements and of computational simulations by molecular dynamics (MD) approach. The results are expressed in storage and loss modulus components (E′ and E″). The role of drying temperature, time, and residual solvent content were studied on the E′ and E″ of prepared PANI–EB films. Using the principle of time–temperature superposition, E′ and E″ at different temperatures and frequencies can be plotted on master curves. The relationship between the modulus components with the solvation level of PANI–EB film is also studied. MD simulation is applied to study the viscoelasticity of simulated PANI structures with different monomeric aniline chains. The temperature dependence of viscoelastic properties provides good information for fractional free volume, cavity size distribution, and activation energy of PANI structures. Simulation outcomes provide a fairly good compatibility with the experimental results. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41858.     

Structural,magnetic, electrical,and electrochemical properties of Sr–Co–Ru–O: A hybrid‐capacitor application

In this study, we report the synthesis of SrCo_1?xRu_xO_3?δ nominal compositions, where x = 0.0‐1.0, using solid‐state reaction technique. XRD analysis confirms the structure of x = 0 sample as hexagonal Sr₆Co₅O₁₅. As the Co ions are substituted by Ru, a two‐phase structure (hexagonal R32 and orthorhombic Pbnm) emerges up to x ≤ 0.5. As the Ru content is increased further, the hexagonal R32 phase disappears completely and an orthorhombic Pbnm phase becomes the main phase. SEM images show that grain size of the samples decreases with increasing Ru content. Temperature‐dependent electrical conductivity studies indicate upon Ru substitution in the nominal SrCo_1?xRu_xO_3?δ compounds, resistivity decreases due to appearance of metallic SrRuO₃ phase. The cyclic voltammogram (CV) of the samples show capacitive properties upon Ru substitution. The cycle measurements of the capacitors yield promising results for potential supercapacitor applications.     

Lewis acid–base properties of cellulose acetate phthalate‐polycaprolactonediol blend by inverse gas chromatography

The net retention volumes, V_N, of n‐alkanes and five polar probes are determined on cellulose acetate phthalate–polycaprolactonediol blend column by inverse gas chromatography in the temperature range 323.15–363.15 K. The dispersive surface energy, $\gamma _{\bf S}^{\bf d}$ , of the blend has been calculated using the V_N values of n‐alkanes and the $\gamma _{\bf S}^{\bf d}$ at 333.15 K is 12.6 mJ/m². The $\gamma _{\bf S}^{\bf d}$ values are decreasing linearly with increase of temperature. The V_N values of the five polar solutes are used to calculate the specific component of the enthalpy of adsorption, ${\Delta }{H}_{\bf a}^{\bf S}$ . The Lewis acid–base parameters, K_a and K_b, are derived using ${\bf \Delta }{H}_{\bf a}^{\bf S}$ values and are found to be 0.019 and 0.403, respectively. The K_a and K_b values indicate that the blend surface contain more basic sites and interact strongly with the acidic probes. The acid–base parameters have been used to analyze the preferential interaction of the solid surface with acidic and basic probes. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers     

Characterization and Mechanical Properties of Calcium Silicate/Citric Acid–Based Polymer Composite Materials

Optimal implants for bone tissue engineering require sufficient mechanical strength as well as apt bioactivity and biodegradability. Calcium silicate (CaSiO₃ ‐ CS) ceramics have been studied for tissue engineering and implantation for their good bioactivity properties. Elastomer poly (1.8‐octanediol citrate) (POC), one of the most biocompatible polymer, is used for biomedical application. The objective of this study is to fabricate a novel composite of calcium silicate with different ratios of POC to enhance the mechanical properties. The results showed that the compressive and the bending strengths of calcium silicate/POC biocomposite were improved remarkably at 40 wt% POC.     

Supercritical fluid dyeing of synthetic and natural textiles – a review

Supercritical fluid dyeing is an interesting alternative to the conventional aqueous process because of its environmental benefits. The aim of the paper is to provide the reader with an up‐to‐date overview of this subject, covering various aspects, such as the solubility and equilibrium partitioning of the dyes, mass transfer phenomena and solvent–polymer interactions occurring during coloration, up to the most recent reports on the technology of the dyeing process. Even though the best results have been obtained in the coloration of synthetic textiles, particular attention is given to the dyeing of natural textiles, which is, at the moment, the limiting step of this technology.     

PP–elastomer–filler hybrids. I. Processing,microstructure, and mechanical properties

Three-component systems with a polypropylene (PP) matrix consisting of polar elastomer (ethylene–propylene rubber and styrene–ethylene–butylene–styrene grafted with maleic anhydride) or of polar PP (PP grafted with maleic anhydride) and filler were investigated. Three microstructures of PP–elastomer–filler hybrids were obtained by processing control and elastomer or PP modification with the maleic anhydride: fillers and rubber particles were separated in the PP matrix, rubber particles with filler core were distributed in the PP matrix, and mixed microstructures of the first and second. A study of mechanical properties showed that the elastic modulus increased in the first microstructure and impact strength increased in the second microstructure. Mechanisms for the relationships between microstructure, processing, and mechanical properties are discussed. © 1996 John Wiley & Sons, Inc.     

Synthesis,characterization, and properties of silicone–epoxy resins

Silicone–epoxy (SiE) resins were synthesized through the hydrolytic condensation of 2‐(3,4‐epoxycyclohexylethyl) methyldiethoxysilane (EMDS) and the cohydrolytic condensation of EMDS with dimethyldiethoxysilane. Structural characterization was carried out by ¹H‐NMR, ²⁹Si‐NMR, and mass spectrometry analysis; the resins were linear oligomers bearing different numbers of pendant epoxy groups, and the average number of repeat Si O units ranged from 6 to 11. Methyhexahydrophthalic anhydride was used to cure the SiE resins to give glassy materials with high optical clarity. The cured SiE resins showed better thermal stability and higher thermal and UV resistances than a commercial light‐emitting diode package material (an epoxy resin named CEL‐2021P). The effect of the epoxy value on the thermal and mechanical properties and the thermal and UV aging performances of the cured SiE resins were investigated. The SiE resins became more flexible with decreasing epoxy value, and the resin with the moderate epoxy value had the highest thermal and UV resistances. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Acrylic pressure‐sensitive adhesives with nanodiamonds and acid–base dependence of the pressure‐sensitive adhesive properties

A high performance and functional properties in pressure‐sensitive adhesives (PSAs) are attractive in fundamental and industrial fields. To control the performance of PSAs, nanofillers have been loaded into them. In this study, we focused on composites of acrylic PSAs and nanodiamonds (NDs). The loaded NDs reinforced the mechanical properties and increased the performance of the PSAs. NDs in a PSA formed a network structure. In this study, we revealed that the acidic–basic state was a key factor in the control of the dispersion of the NDs. When a PSA emulsions and ND aqueous dispersion was mixed under basic conditions, the composites demonstrated higher PSA properties (tack, holding, and peeling strength). We investigated the effect of the ND loading on the PSA properties from the viewpoints of the nanostructure and acid–base interactions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46349.     

Study on ozone bleaching of cotton fabric – process optimisation, dyeing and finishing properties

In this work the role played by the presence of moisture and pH during ozone bleaching of grey cotton fabric and the design features of the ozone application chamber are reported. The results are explained with the help of a simplified model. The dyeing and resin finishing properties of ozone-bleached fabric are compared with those of hydrogen peroxide-bleached fabric.