Synthesis, Characterization and Surface Properties of Cross-linked Polyurethane Dispersions Modified by Organosiloxane

A series of cross-linked polyether-polyester polyurethane dispersions modified with organosiloxane were prepared based on hydroxyl-terminated polydimethylsiloxane (HTPS) as hydrophobic component and 3-aminopropyl-triethoxysilane (APTS) as cross-linker as well as a bridge between polyurethane (PU) and polysiloxane (PSIL). It was discovered that polydimethylsiloxane segments were incorporated into PU chains chemically and organosiloxane was preferentially oriented toward the surface layer of the film by making a comparison of attenuated total reflection (ATR) spectra between the copolymer and the blend of PU and PSIL, which was further confirmed by investigation of electron spectroscopy for chemical analysis (ESCA). The relationships between surface properties of the film formed from polyurethane dispersion and organosiloxane content were also studied. The results showed that water contact angle of the film increased with the increase of organosiloxane content. Interestingly, it was also found that water contact angle of PUS film increased firstly and then decreased when film-forming temperature varied from 25℃ to 55℃.     

Synthesis and Surface Properties of Dicephalic Surfactants with a 1,3-Dioxane Ring

A new group of surface active dicephalic derivatives of 1,3-dioxane, i.e., 2-alkyl-5,5-bis{[3-(N,N-dimethylamino)propyl]amido}-1,3-dioxane-di-N-oxides, were synthesized with high yields by the reaction of an appropriate 2-alkyl-5,5-bis-(carboxyethyl)-1,3-dioxane with an excess of N,N-dimethyl-1,3-propanediamine followed by oxidation with an aqueous solution of hydrogen peroxide. Structures and purity of all intermediates and final di-N-oxides were confirmed by means of ¹H-NMR and ESI-MS spectroscopy. Synthesized compounds showed high surface activity with low values of critical micelle concentration and high effectiveness of surface tension reduction (γ _CMC). However, only derivative with the longest 2-alkyl substituent showed good foaming and moderate emulsifying properties.

Synthesis,Surface Properties,and Inhibiting Action of Novel Nonionic Surfactants on Carbon Steel Corrosion in 1 M Hydrochloric Acid Solution

In the present study novel nonionic surfactants were synthesized, characterized, and tested as corrosion inhibitors for carbon steel in 1 M HCl solution. The inhibiting performances of these surfactants were studied by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The adsorption of these inhibitors was well described by Langmuir adsorption isotherm, and the kinetic parameters were calculated and discussed. The inhibition efficiency (IE) was found to rise with increasing the concentration of these inhibitors. Polarization measurements revealed that the inhibitors acted as mixed-type inhibitors. The efficiencies obtained from the impedance measurements were in good agreement with those obtained from the weight loss and potentiodynamic polarization techniques which prove the validity of these tools in the measurements of the tested inhibitors. The surface parameters of the synthesized nonionic surfactants were investigated and the results showed that these surfactants have lower values of surface tension and are effective as wetting and emulsifying agents.     

Synthesis,Characterization and Ion–Exchanging Properties of Novel Ion-Exchange Resin,Part 1

A polyamine (PA) was prepared by condensation of 1,4-bischloromethyl benzene and 1,2-ehanedeamine. The PA was then treated with cyanuric chloride at 0°C followed by reaction with sulfanilic acid in THF in concentration. NaOH (PH 9–10) at room temperature for 8 h. The resultant polymer, designated as polyamine-s-triazine-sulfanilic acid (PATS), was characterized by elemental analysis, IR spectral studies, and thermogravimetry. The PATS sample was monitored for its ion-exchanging properties by batch equilibrium method.     

Synthesis and Interface Activity of a Series of Dicarboxylic Cationic Surfactants and a Structure–Efficiency Relationship Study

Quaternary ammonium cationic surfactants are widely used in many fields, but information about the effect of the anion on cationic surfactants is scarce. To study the effect of anions on the surface properties, six dicarboxylic cationic surfactants were prepared, (cetyltrimethylammonium oxalate, CTAO; cetyltrimethylammonium malonate, CTAM; cetyltrimethylammonium succinate, CTASU; cetyltrimethylammonium glutarate, CTAG; cetyltrimethylammonium adipate, CTAA; and cetyltrimethylammonium sebacate, CTASE), and their surface properties were studied, including surface tension, critical micelle concentration, foaming ability and stability, and corrosion inhibition. The results showed that the minimum surface tension followed the order of CTAO<CTAM<CTASU<CTAG<CTAA<CTASE. The foaming ability followed the order of CTAO>CTAM>CTASU>CTAG>CTAA>CTASE. The foaming stability followed the order of CTAM>CTAO>CTASU>CTAG>CTAA>CTASE. At a concentration of 1.0 g L⁻¹, the order of emulsification power of these surfactants was CTASE<CTAO<CTAA<CTAG<CTASU<CTAM, and at 5.0 g L⁻¹, the order was CTASE<CTASU<CTAA<CTAG<CTAO<CTAM. The corrosion inhibition efficiency on mild steel followed the order of CTASE<CTAA<CTAG<CTASU<CTAM<CTAO.     

Synthesis,Quantum Chemical Calculations and Properties of Nonionic and Nonionic–Anionic Surfactants Based on Fatty Alkyl Succinate

Two surfactants based on maleic anhydride were synthesized by esterification with fatty alcohols C₁₀, C₁₂ and C₁₄ to produce half esters [I–III]. Nonionic surfactant monoesters [I–III]a–c synthesized by ethoxylation of [I–III] with different moles of ethylene oxide [6, 8 and 10] in the presence of K10 clay as an untraditionally catalyst. The later products were sulfonated to produce nonionic–anionic surfactants [IV–VI]a–c. The structures of synthesized surfactant were elucidated by FTIR and ¹H-NMR data. Their surface activity and biodegradability were determined. All the synthesized surfactants showed good surface activity and biodegradability, but anionic-nonionic type has better effect than nonionic one. Quantum chemical calculations were utilized to explore the electronic structure and stability of these compounds. Computational studies have been carried out at the PM3 semiempirical molecular orbitals level, to establish the highest occupied molecular orbital–lowest unoccupied molecular orbital, ionization potential energy and ESP mapping of these compounds. Also, the absorption, distribution, metabolism, elimination and toxic properties were studied to gain a clear view of the oral bioavailability of these compounds.     

Synthesis and Characterization of Some Poly(1,2-Phenylenedithiocarbamate)–Metal Complexes

Poly(1,2-phenylenedithiocarbamate) (PPDTC) was prepared by the reaction of 2-aminothiophenol with carbon disulfide followed by condensation through the removal of H₂S gas. PPDTC was used as a ligand to prepare four poly(1,2-phenylenedithiocarbamate)–metal complexes of iron(II), cobalt(II), copper(II), and lead(II), by refluxing with the metal salts. The polymer and its metal complexes were investigated by elemental analyses, UV–visible and IR spectroscopy, inherent viscosity, and magnetic susceptibility. The DC electrical conductivity variation with the temperature in the range 298–498 K of PPDTC and its polymeric copper complex was measured. Both polymer and polymer metal complexes showed an increase in electrical conductivity with an increase in temperature: typical semiconductor behavior. The proposed structure of the complexes is (MLX₂·mH₂O) _n .     

Synthesis,Characterization, and Micellization Behavior of Cationic Surfactants: n-Alkyl-3-Methylpyridinium Bromides and Their Drug Interaction Study by UV–Visible Spectroscopy and Conductometry

The synthesis of new cationic surfactants i.e., n-hexyl-3-methylpyridium bromide ( a ) and n-octyl-3-methylpyridium bromide ( b ), and their characterization using multinuclear nuclear magnetic resonance spectroscopy (NMR) (¹H, ¹³C) and Fourier-transform infrared spectroscopy (FT-IR) spectroscopic techniques were reported. The micellization behavior of the synthesized surfactants was studied using conductometry and ultraviolet–Visible spectroscopy. The critical micelle concentration (CMC) of compounds a and b was found to be 0.41 and 0.35 m mol L⁻¹, respectively. The effect of temperature on the CMC of these compounds was examined in the range of 298–318 K and thermodynamic parameters (ΔG, ΔH, and ΔS) of the micellization process were calculated. The antibacterial study of the synthesized surfactants revealed their strong activity against different bacterial strains. Moreover, the interaction of drugs i.e., flurbiprofen and ketoprofen, with the synthesized surfactants was investigated for gaining insights into the role of micelles as drug-delivery devices. Drug–surfactant interactions were also confirmed via a conductometric method.     

Synthesis,Characterization and Adsorptive Properties of Quaternized 2-Dimethylaminoethyl Methacrylate Based Polymer–Clay Nanocomposites

[2-(Methacryloyloxy)ethyl]dimethylhexadecylammonium bromide (QDMA) was synthesized by means of quaternization of 2-dimethylaminoethyl methacrylate. Poly(QDMA) and poly(QDMA)-bentonite nanocomposites containing different amount of bentonite were prepared by in situ suspension polymerization and characterized. Adsorption behaviors of these materials towards acid orange 8 and p-nitrophenol were investigated with respect to solution pH. For both adsorbate, adsorption capacities of some nanocomposites were found to be higher than those of bentonite and poly(QDMA). Effects of various parameters such as contact time, initial adsorbate concentration, and temperature on the adsorption of acid orange 8 and p-nitrophenol onto NC3 from aqueous solutions were also evaluated.     

Preparation, Characterization, and Photoelectric Properties of Langmuir–Blodgett Films of Some Europium-Substituted Polyoxometalates and 2-Aminofluorene with Tunable Emission Color

A new series of organic/inorganic composite Langmuir–Blodgett (LB) films consisting of 2-aminofluorene (Fl–NH₂) as the π-conjugated organic molecule, an europium-substituted polyoxometalate (POM, POM = Na₉EuW₁₀O₃₆, K₁₃[Eu(SiW₁₁O₃₉)₂] and K₅[Eu(SiW₁₁O₃₉)(H₂O)₂], which are denoted by EuW₁₀, EuW₂₂ and EuW₁₁, respectively) as the inorganic component, were prepared. Structural and photophysical characterization of these LB films were achieved by π–A isotherms, UV–Vis absorption and photoluminescence spectra, atomic force microscopy imaging, scanning tunneling microscopy, and surface photovoltage spectroscopy. Our experimental results indicate that stable Langmuir and LB films are formed in pure water and POM sub-phases. Luminescence spectra of the prepared hybrid LB films show that tunable emission color can be obtained due to the dual-emissive nature of the mixed Fl–NH₂/POM blends. These 2-aminofluorene-based LB films displayed interesting electrical conductivity behavior. Among them, Fl–NH₂/EuW₁₁ 3-layer films showed a good electrical response with the a tunneling current up to ± 100 nA when the voltage was monitored at ?0.8 to 1.5 V. These LB composites show good photovoltage responses and a photovoltage of 2.7 μV can be obtained for the Fl–NH₂/EuW₂₂ system when it is excited by light.     

Synthesis,Characterization, and Reaction of Divinyl‐substituted Laddersiloxanes

Silicon - Silsesquioxanes with well-defined structures have been of great interest recently because of their superior properties. Among them, laddersiloxanes (ladder-type silsesquioxanes with...     

Synthesis,Characterization and Curing of o-Cresol – Furfural Resins

Polycondensation of o-cresol (OC) with furfural (F) was carried out under various reaction conditions. The resultant resin samples designated as OCFs were characterized by elemental analysis, spectral studies, viscometric measurement of solution in 1,4-dioxane and by the estimation of the number – average molecular weight. Thermogravimetric analysis (TGA) of selected resin samples has been carried out. The curing kinetic reaction of selected OCF resin samples was studied by differential scanning calorimetry (DSC). Hexamethylenetetramine (Hexamine) has been used as curing reagent.     

Synthesis,Characterization, and Spectroscopic Analysis of NdxY1−xTiNbO6 Microwave Ceramics

Solid solutions of Nd_xY_1−xTiNbO₆ ceramics were prepared through the solid-state ceramic route. The materials were calcined at 1250°C and sintered in the range 1400–1550°C. The structure of the system was analyzed using the X-ray diffraction and vibrational spectroscopic analysis. The morphology and the sintering behavior of the samples were analyzed using scanning electron microscopy. The dielectric constant (ɛ_r), temperature coefficient of resonant frequency (τ_f), and the unloaded quality factor (Q_u) were measured in the microwave frequency region using the cavity resonator method. The ɛ_r and τ_f increased with an increase in the concentration of Nd in the solid solutions. Nearly zero temperature coefficient of resonant frequency was obtained for the Nd_0.6Y_0.4TiNbO₆ ceramic. Samples are of high quality factor and are useful for microwave applications.     

Organic–Inorganic Incompletely Condensed Polyhedral Oligomeric Silsesquioxane-Based Nanohybrid: Synthesis,Characterization and Dye Removal Properties

A nanocomposite was developed from organic–inorganic hybrid of incompletely condensed polyhedral oligomeric silsesquioxane nanoparticles and poly (acrylamide-co-hydroxyethyl methacrylate) with properties of hydrophobicity of incompletely condensed polyhedral oligomeric silsesquioxane and dye adsorption capacity of the copolymer. The as-prepared nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. The synthesized hybrid nanocomposite acquires extraordinary water remediation property after the removal of toxic dye from aqueous solution. Conditions for the adsorption of dye by the hybrid nanocomposite have been also optimized. In addition, the adsorption mechanism was studied.     

Synthesis, Surface Properties, Synergism Parameter and Inhibitive Performance of Novel Cationic Gemini Surfactant on Carbon Steel Corrosion in 1 M HCl Solution

Electrochemical and gravimetric measurements were performed to investigate the effectiveness of a synthesized cationic gemini surfactant as corrosion inhibitor for carbon steel in 1 M HCl solution. The inhibition efficiency obtained from all methods are in good agreement. Potentiodynamic polarization measurements showed that, the prepared surfactant hinders both anodic and cathodic processes, i.e. acted as mixed-type inhibitor. It was found that the adsorption of the synthesized inhibitor followed the Langmuir adsorption isotherm and showed a mixed physical and chemical adsorption. Kinetic parameters were calculated and discussed. The inhibitor exhibited a synergistic effect with Sn²⁺ more than with Cu²⁺. The synthesized cationic gemini surfactant exhibited good surface properties.     

Plasticization of Fibrous Cellulose Acetate: Part I – Synthesis and Characterization

Synthesis and characterization of fibrous cellulose triacetate, CTA, are reported using an acetic acid/anhydride/perchloric acid toluene catalyzed route. The fibrous product exhibits a high degree of nano-crystallinity. An optimum concentration of the reactants for substitution and minimization of fiber degradation was studied. Chain degradation was promoted by the acetylium ion and led to a loss of fibrous structure. Heterogeneity of the material was studied by powder X-ray diffraction, optical microscopy, and solid-state ¹³C nuclear magnetic resonance. The structure formed if directly influenced by the original nano structure in the cellulose fiber.     

Silicon-Containing Carbonates—Synthesis,Characterization, and Additive Effects for Silicon-Based Polymer Electrolytes

New silane and siloxane compounds containing cyclic carbonate functional groups were synthesized and characterized. The compounds were prepared via two routes: hydrosilation of SiH containing siloxanes and alcoholysis of chlorosilanes with hydroxy-terminated oligoethers. The products were purified by distillation and solvent extraction and characterized using ¹H, ¹³C, and ²⁹Si NMR. Upon doping with lithium bis(oxolato)borate (LiBOB), the conductivities of the compounds were determined. These carbonate compounds themselves did not show promising conductivities. However, when used as additives to silicone-containing oligoether electrolytes, the conductivities of the resulting mixtures were increased by up to 35%.