Phenolsulfonic Acid Research Articles

Effect of PSA tin plating process on trace lead in tin coating

In this paper, effects of conditions in phenol sulfonic acid (PSA) plating for tin coating of MR low carbon aluminum killed steel on trace Pb were examined. Trace Pb was measured by atomic absorption spectrometry (AAS) and glow discharge spectrometry, and coating morphology was observed by scanning electronic microscopy (SEM). Corrosion resistance of the tin coating was analyzed by electrochemical methods. The results indicated that Pb content in the tin coating reduced as bath temperature increased. When the temperature exceeded 40°C, the grains in the coating were coarse and loose, reducing the corrosion resistance. As current density increased, Pb content increased rapidly, while low current density plating could lead to drain regions. The plating speed had no obvious effect on trace Pb in tin coating. In the tin plating layer, Pb was enriched at the surface and gradually reduced to zero along the depth. At bath temperature of 40°C and current density of 20A·dm−2, the amount of Pb could be less than 100mg·kg−1 with excellent corrosion resistance.

Tin Coatings Electrodeposited from Sulfonic Acid-Based Electrolytes: Tribological Behavior

A high efficiency methane sulfonic acid electrolyte used for tin electrodeposition was studied, and the properties of the resulting deposits were compared to those of tin coatings obtained from an industrial phenol sulfonic acid electrolyte. Cyclic voltammetry was used to study the effect of organic additives on the reduction process to define the composition of the electrolytic bath. Thick tin electrodeposits were obtained on rotating cylinder steel electrodes, and their surface morphology, preferred crystal orientation, surface roughness, micro hardness, and tribological behavior were measured. Smooth, adherent, and bright tin coatings were obtained from the methane sulfonic acid electrolyte, which differed in morphology and texture from tin electrodeposited from the industrial bath. Influence of organic additives on preferred crystal orientation of the coatings was found to be stronger than changing the supporting sulfonic acid type. Tribological tests showed that the two types of deposits have a similar coefficient of friction. However, tin coatings obtained from methane sulfonic electrolytes presented a lower wear resistance and underwent galling at lower loads.

Crystallographic texture of light tinplate coatings made in various electrolytes

Two electrolytic tinplating processes are currently used in Europe: PSA (based on phenolsulfonic acid) and MSA (based on methanesulfonic acid). The Halogen Process is used in other parts of the world. The electrolyte composition and process parameters affect the electrodeposit and ultimately the tinplate appearance and performance. In order to better understand the impact of electrolyte composition on the crystallographic texture of tin coating tinplate, light tin coatings on single reduced, continuously annealed (CA) tinplate produced in three electrolytes: Halogen, PSA and MSA were analyzed. The crystallographic texture of thin tin coating (<2.8gm-2) was analyzed by X-ray Diffraction and Electron Backscatter Diffraction. The effect of reflow (melting of the tin followed by rapid solidification) and ironing during drawn and wall ironed (DWI) can forming on the tin crystallography were evaluated. Both texture analysis by XRD and EBSD confirmed that all un-melted tin coatings, made in three different electrolytes, contain texture fibers. The effect of steel sheet crystallographic texture was investigated by comparing the tin crystallographic orientation on continuously annealed steel substrate (with α and γ fiber texture) versus batch annealed (BA) steel with a strong γ fiber texture. The main electrolytic parameters, current density and line speed, did not affect the texture formation of tin coating produced in MSA-based electrolyte within the commercial ranges. Un-melted tin coatings produced in the MSA-based electrolyte showed sharper texture than those produced in PSA and Halogen electrolytes. The FeSn2 alloy structure was not observed in un-melted tin coatings; however, it was detected after ironing in the DWI process.

Preparation and characterization of non-isocyanate polyurethanes based on 2-hydroxy-6-naphthalenesulfonic acid as a monomer of the rigid phase

Abstract The present study investigates the properties and structure of condensation non-isocyanate polyurethanes (NIPURs) prepared by reacting 2-hydroxy-6-naphthalenesulfonic acid (HNSA) with phenolsulfonic acid, urea and formaldehyde. Instrumental analyses confirmed a linear and segmented structure of the obtained condensation NIPURs. It was found that NIPUR films containing 20% HNSA and an equimolar ratio of rigid to flexible segments exhibited maximum values of tensile strength and tensile strain at break. All prepared samples showed a very high water resistance. The operating temperature of NIPUR samples based on HNSA was set between -33°C and +145°C. The first temperature was attributed to the glass transition of flexible segments, while the second one was associated with rigid segments melting. The higher the transition temperature, the higher the rigid segment content and the higher the HNSA content in the NIPUR sample.

MALDI-TOF and 13C NMR Analysis of Tannin–Furanic–Polyurethane Foams Adapted for Industrial Continuous Lines Application

Mixed phenolic-polyurethane-type rigid foams were developed using tannin-furfuryl alcohol natural materials co-reacted with polymeric isocyanate in the proportions imposed by the limitations inherent to continuous industrial plants for polyurethane foams. A variety of different copolymerization oligomers formed. Urethanes appeared to have been formed with two flavonoid tannin sites, mainly at the flavonoid hydroxyl group at C3, but also, although less, on the phenolic hydroxyl groups of the flavonoid oligomers. Urethanes are also formed with (i) glyoxal in the formulation, be it pre-reacted or not with the tannin; (ii) with phenolsulfonic acid and (iii) with furfural. This latter one, however, greatly favors reaction with the A-ring of the flavonoids through a methylene bridge rather than reaction with the isocyanate groups to form urethanes. All of the materials appeared to have co-reacted in a manner to form urethane and methylene bridges between all of the main components used. Thus, the tannin, the furfuryl alcohol, the isocyanate, the glyoxal and even the phenol sulfonic acid hardener formed a number of mixed species linked by the two bridge types. Several mixed species comprised of 2, 3 and even 4 co-reacted different components have been observed.

Bronze electrodeposition from an acidic non-cyanide high efficiency electrolyte: Tribological behavior

Bronze coatings were electrodeposited onto a rotating cylinder electrode from a novel non-cyanide acid plating bath with high efficiency (92%). Deposits were obtained from a phenol sulfonic acid bath and their morphology, phase composition and tribological behavior were characterized. Cyclic and linear sweep voltammetries were used to study the effect of organic additives on the reduction processes to achieve an adequate formulation. The resulting bronze deposit consisted of a mono α-phase matrix with a 78% Cu and 22% Sn composition. Dry sliding wear tests were carried out employing a homemade ball on ring system and the coefficient of friction and wear resistance were quantified at different normal loads. Surface characterization of the bronze coatings showed that the resulting roughness is detrimental for the wear resistance of the deposit. This is evidenced by a higher friction coefficient and wear volume of Cu/Sn compared to a conventionally electrodeposited copper coating.

Comparison of four methods for determination of soluble silicon in freshwater

Four photocolorimetric methods have been comparatively studied for determining soluble silicon in freshwater. Meanwhile,the effects of glass containers on the determination and the interference of the phosphate ion on chromogenesis were also investigated. It was demonstrated that 1,2,4-trichlorobenzene amino phenol sulfonic acid reduction-silicon molybdenum blue method is highly sensitive and accurate for the determination of soluble silicon in fresh water,and has an optimal concentration range from 0. 05-20 mg / L. Ascorbic acid reduction-silicon molybdenum blue method and metol reduction-silicon molybdenum blue method are highly sensitive but less accurate; silicon molybdenum yellow method is simple in operation but with low sensitivity. Glass containers used do not influence the determination by the four methods,and the interference of phosphate ion could be eliminated.

Synthesis and evaluation of mechanical and thermal properties of segmented condensation polyurethanes

Condensation polyurethanes with different hard segment (HS) content were prepared by condensation reaction of urea, phenol sulphonic acid and formaldehyde and tested for their mechanical, physical and thermal properties. Obtained polyurethane (PUR) films were first heated at 50°C for 120 min and then treated at 135°C for 15 min or 160°C for 10 min. The tensile strength of samples thermally treated at 50°C then at 135°C was 120% higher than for samples treated only at 50°C. The obtained polyurethanes exhibited segmented structures with phase separation between HSs and soft segments (SSs). Films containing 19 and 21%HSs heated at 50°C then 135°C exhibited acceptable mechanical properties and water resistance. The lower and higher end use temperatures of PUR films were affected mainly by the polymer composition. Moreover, the polyurethane samples containing 19 and 21%HSs have shown the highest decomposition temperature (i.e. >165°C), compared to 80°C for polymers with 32%HSs.

Effect of sulphonic acids on electrodeposition of nickel and its structural and corrosion behaviour

The influence of methane sulphonic acid, naphthalene sulphonic acid and phenol sulphonic acid on the electrodeposition of nickel from a citrate buffered nickel bath was investigated. Solution characteristics such as cathode efficiency and throwing power have been assessed, and corrosion resistance of the coatings was measured by electrochemical impedance spectroscopy method. The X-ray diffraction pattern obtained for electrodeposited nickel showed a polycrystalline fcc structure. A uniform and pinhole free surface was observed under SEM analysis.

Preparation and properties evaluation of nonisocyanate condensation polyurethanes based on phenol sulfonic and hydroxybenzoic acids

The present work investigates the preparation of nonisocyanate polyurethane through condensation of oligomeric hard segments produced by using phenol sulfonic and hydroxybenzoic acids and soft segments obtained by transesterification reaction of polyoxypropylene glycol with ethyl urethane. Obtained nonisocyanate polyurethane films with different hard segments content were tested for their mechanical, physical and thermal properties. Polyurethane films containing p-hydroxybenzoic acid exhibited enhanced tensile strength and water resistance. The tensile strength increased by approximately 230% and water resistance by 35% with the addition of 30% p-hydroxybenzoic acid. Differential scanning calorimetry analysis confirmed the formation of segmented structures within the prepared condensation nonisocyanate polyurethane-based films. Moreover, Fourier transform infrared spectroscopy results analysis confirmed the chemical structure of condensation polyurethanes with characteristic groups of typical conventional polyurethanes.

Pulse electrodeposition of tin from sulphate bath

In the present work, the pulse electrodeposition of tin from sulphate bath containing SnSO4, H2SO4, phenol sulphonic acid, gelatin and β-napthol has been studied. The influences of pulsed current, duty cycle on the thickness, hardness and current efficiency of the tin deposit were studied. Electrochemical corrosion studies of the deposited tin on mild steel were conducted by potentiodynamic polarisation and electrochemical impedance spectroscopy. Cyclic voltammetry studies using potential sweep of 10 mV s–1 provide information about the potential ranges for tin deposition and stripping. The tin deposit on a brass substrate has been investigated using XRD, SEM and AFM. The XRD analysis revealed that the tin plated is Sn(200) and crystalline. The morphology of tin deposit is a typical fine grained and granular structure as seen from SEM and AFM.

Simulation of proton migration pathways in phenolsulfonic acid-based membranes by B3LYP/6-31G** DFT calculations

Geometrical and energetic characteristics of clusters simulating crystal hydrates of phenolsulfonic acid (PSA) and its complexes with poly(vinyl alcohol) (PVA) and the pathways of proton transport therein were determined using the DFT (B3LYP) theory with the 6-31G** basis set. In the formation of proton-conducting PVA—PSA-based membranes, it is energetically favorable to have at least one water molecule in close proximity of the SO3H fragment. In water-free media, the proton migration along the SO3H group is hindered by a barrier of 30–34 kcal mol−1. In the presense of water, the proton conductivity follows the relay mechanism with the activation barrier of 5–8 kcal mol−1, which is close to the experimetally observed barrier of 4–6 kcal mol−1. Thus, the relay mechanism of proton transfer in a sulfonic acid—water complex is energetically the most favorable. The most energetically favorable isomer is the one with the PSA and PVA fragments H-bonded through a water molecule. The deficiency of water causes the PVA OH protons to be involved in hydrogen bonding as well. The role of PVA is to align the acid molecules and participate in the relay proton transfer. Introduction of an aldehyde into the membrane results in significant improvement of its physical properties. The aldehyde reacts with the hydroxyl groups of PVA. At high humidity, one may expect little effect of the degree of cross-linking on the proton mobility.

Proton conductivity in phenolsulfonic acids and their salts

The geometric parameters and energies of crystal hydrates of aromatic sulfonic acids and their salts, as well as the pathways of proton transport in them, were calculated by the DFT (B3LYP) method with the 6-31G** basis set. For aromatic sulfonic acids, the proton relay mechanism was shown to be energetically more favorable than rotation of the HSO group or direct proton transfer. Calculations show that an increase in the number of water molecules located near the HSO3 group from one to four decreases the barrier from 6 to 0.3 kcal/mol. Hence, a moderate increase in humidity should enhance the conductivity, which is fully consistent with experimental data. Calculations predict that the salts where all protons are substituted by metal atoms are unlikely to show good conductivity. Conversely, mixed salts, for example, H3C6(OH)(NaSO3)(HSO3) and H3C6(OH)(RbSO3)(HSO3), are expected to be thermally stable and resistant to deliquescence with an increase in the humidity of a medium and to have good conductivity.

TITANIUM-CARBIDE-INFUSED PHENOLIC BALSA FOAM NANOCOMPOSITE

A sonochemical technique is developed to infuse titanium carbide nanoparticles into phenolic balsa foam material. Commercially available phenolic balsa foam resin solution (part A) is mixed with titanium carbide ( TiC ~ 80 nm ) nanoparticles, and irradiated with a high intensity ultrasonic horn. In the next step, the modified phenolic balsa foam resin solution containing titanium carbide nanoparticles is mixed with part B (containing phenol sulfonic acid, a catalyst) through a high speed mechanical stirrer. The reaction mixture is then cast into a rectangular mold to fabricate nanophased foam panels. Test coupons are cut precisely from the panels to carry out thermal, morphological and mechanical characterizations. The as-prepared foams are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The SEM studies show that the particles are well dispersed over the entire volume of the matrix, with minimal agglomeration. The foam cell structures are well-ordered and uniform in size and shape. The TGA analysis indicates that the nanophased foams are thermally more stable than the corresponding neat systems. Quasi-static compression tests have been carried out for both nanophased and neat foam systems. The test results show a significant increase in the compressive strength (108%) and modulus (135%) compared to the neat system. These improvements in compressive properties have been observed repeatedly for multiple batches and with a minimum of five specimens tested from each batch. Details of the synthesis procedure and thermal and mechanical characterizations are presented in this paper.

Hide tanning with modified natural tannins

AbstractTannin from “Acacia Mearnsii” usually called Mimosa, is largely employed in vegetal tanning of hide even if the quality of the leather is poorer than that obtained using chromium as tanning agents. However, taking into account the natural resources of this product and its reduced environmental impact, mimosa tannin has been modified to obtain leather having improved properties. Tannin was modified using formaldehyde, urea, a sulfonic acid and a sulfiting agent: The new products show a higher molecular weight than mimosa tannin but maintain a good solubility in water. Modified tannins were characterized through physicochemical and technological tests and evaluated as tanning agents. The properties of tanned leathers obtained using the new tannin products and mimosa were compared. Some of the polymers containing phenolsulfonic acid are good tannin agents, especially those with a suitable molecular weight. The technological and sensorial properties of the leather obtained using modified tannins (distension and strength of grain, tensile strength, elongation, and tear load) are better than those obtained using mimosa when an appropriate ratio of the reagents were employed. At the same time the feeling of the tanned leather was improved and the final products show fullness, elasticity, fluency, reactivity, and a thin and fine grain. Some of the tannins modified with naphtalensulfonic acid show poor tanning properties but good penetration in the leather suggesting their use as auxiliary sintans in the pretanning process. A simple procedure to prepare these modified tanning agents in the course of the tannin extraction is suggested. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Modeling the hydration and proton transport in solid electrolytes based on phenolsulfonic acids

Geometrical and energetic characteristics of crystal hydrates of individual aromatic sulfonic acids and their complexes with poly(vinyl alcohol) as well as the paths for the proton transport in them are calculated in the framework of the density functional theory (version B3LYP) employing the 6-31G** basis set. The energy of attachment of water to ortho -substituted aromatic sulfonic acids is demonstrated to diminish from 74.4 to 54.8 kJ mol -1 in the following series of substituents: -OH, -F, − CH 3 , -H, -Cl, and -COOH. For the dimers that comprise individual phenolsulfonic acids, the energy of attachment of one water molecule to the SO 3 H group is estimated to be equal to 92-105 kJ mol -1 . In the dimers comprising individual phenolsulfonic acids, the specific energy of intermolecular bonds (bond energy per monomer molecule) is found to be equal to 49.3 and 58.5 kJ mol -1 for, respectively, phenol-2,4-disulfo and phenol-2-sulfo acids. During the formation of polymer membranes based on poly(vinyl alcohol) and phenolsulfonic acids, it is energetically favorable that at least one water molecule should remain in the vicinity of the SO 3 H fragment. According to the calculations, the proton migration along the SO 3 H group in anhydrous environment is hampered by a barrier of 125-132 kJ mol -1 . In the presence of water, the proton conductivity is of a relay character, with an activation barrier equal to 21 − 33 kJ mol -1 . The latter value is close to experimental data (17-25 kJ mol -1 ). DOI: 10.1134/S1023193507050023

Cloisite clay‐infused phenolic foam nanocomposites

AbstractA sonochemical technique was developed to infuse Cloisite clay nanoparticles into phenolic foam materials. Phenolic resin solution (Part A) was mixed with clay particles, and irradiated using a high intensity ultrasonic liquid processor. In the next step, the modified phenolic resin solution containing clay particles was mixed with Part B (containing phenol sulfonic acid, catalyst) through a high‐speed mechanical stirrer. The reaction mixture was then cast into rectangular molds to make nanophased foam panels. Test coupons were cut precisely from the panels to carry out thermal, morphological, and mechanical characterizations. The as‐prepared foam samples were characterized by scanning electron microscopy (SEM), X‐ray diffraction, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The SEM studies have shown that the particles are well dispersed over the entire volume of the matrix with minimal agglomeration. The foam cells structures are well‐ordered and uniform in size and shape. The TGA and DSC analyses show that the nanophased foams are thermally more stable than the corresponding neat system. Quasistatic compression tests have been carried out for both nanophased and neat foams systems. The test results show that there is a significant increase (approximately in the range of 150–180%) in the compressive strength and modulus of the nanophased foams over the neat system. This improvement in compressive properties has been noted repeatedly for multiple batches and with a minimum of three specimens tested from each batch. Details of the synthesis, thermal and mechanical characterization are presented in this paper. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 308‐314, 2007

Sn-P Alloys for Rapid and Stable Production of Tin Solution for Tin Plating

For fast preparation of tin solution for electrodeposition, the dissolution characteristics controlled by oxygen reduction were investigated for Sn metal and Sn-P alloys containing cathodic inclusions using electrochemical measurement in p- phenolsulfonic acid. The dissolution rate of tin increased with phosphorus content of the alloys due to faster oxygen reduction and showed the maximum at about 1 at % phosphorus. The cathodic inclusions were dispersed in the Sn matrix by water quenching of molten mixture of Sn and Sn-50at%P, and were identified as the Sn4P3 phase by X-ray diffraction. The Sn4P3 compound has the higher activity for oxygen reduction than Sn metal and platinized platinum. The mechanism for the cathodic reduction of dissolved oxygen on Sn metal and Sn-P alloys was investigated in p-phenolsulfonic acid. Increasing phosphorus content of Sn-P alloys resulted in an increase in the limiting oxygen reduction current density which was proportional to the partial pressure of oxygen, but independent of pH. It was concluded that the rate-determining process of oxygen reduction was adsorption of oxygen molecule on the Sn metal and Sn-P alloys.

Assessment of genotoxicity of 14 chemical agents used in dental practice: Ability to induce chromosome aberrations in Syrian hamster embryo cells

To assess the genotoxicity of 14 chemical agents used as locally applied agents in dental practice, the ability of these agents to elicit chromosome aberrations was examined using Syrian hamster embryo (SHE) cells. Chromosome aberrations in SHE cells were induced by treatment with three of eight chemical agents used as endodontic medicaments, i.e. ethylenediaminetetraacetic acid (EDTA), formocresol (a mixture of formalin and tricresol), and sodium arsenite. The other five chemical agents, i.e. chloramphenicol, p-chlorophenol, p-phenolsulfonic acid, sodium hypochlorite, and tetracycline hydrochloride exhibited a negative response for chromosome aberrations. Assessment of three dyes used for disclosing dental plaque showed chromosome aberrations induced by basic fuchsin but not by acid fuchsin and erythrosine B. Three local anesthetics, lidocaine hydrochloride, prilocaine hydrochloride, and procaine hydrochloride, were negative for chromosome aberrations. Among the ten chemical agents that exhibited a negative response in the assay, p-chlorophenol, sodium hypochlorite, and erythrosine B induced chromosome aberrations in SHE cells when treated in the presence of exogenous metabolic activation. The percentages of cells with polyploidy or endoreduplication were enhanced by formocresol, sodium arsenite, p-chlorophenol, p-phenolsulfonic acid, sodium hypochlorite, erythrosine B, prilocaine hydrochloride, and procaine hydrochloride in the absence or presence of exogenous metabolic activation. Our results indicate that the chemical agents that had a positive response in the present study are potentially genotoxic to mammalian cells.

Effects of Ethoxylated α-Naphtholsulfonic Acid on Tin Electroplating at Iron Electrodes

Effects of ethoxylated α-naphtholsulfonic acid (ENSA) on the initial stages of tin plating have been studied on iron electrodes in an acidic stannous sulfate solution containing phenolsulfonic acid as a supporting electrolyte using potentiodynamic polarization, electrochemical quartz crystal microbalance (EQCM), scanning probe microscopy (SPM), and electrochemical impedance spectroscopy techniques. The smallest exchange current density and a larger transfer coefficient are observed at a typical ENSA concentration used in industrial plating baths, i.e., 0.013 M. The SPM imaging and EQCM measurements show that ENSA molecules form a compact structure by interacting with neighboring molecules at the iron surface, which controls the mass transport for Sn(II) reduction. The EQCM studies indicate that the ENSA molecules remain stably adsorbed on the electrode surface at considerably high overpotentials. The ENSA molecules present in both the tin layers and the solution are found to slow the hydrogen evolution reaction at, as well as the corrosion process of, the tin-plated electrode, acting as an anticorrosion agent in commercial tin plating baths. © 2004 The Electrochemical Society. All rights reserved.