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Polyethyleneglycol borate (PEG-BAE) toughening agents were preparedfrom the esterification reaction between boric acid and PEG and characterizedby FTIR and NMR. The effect of reaction conditions such as reactiontemperatures, reaction times, and entrainer amounts on the esterificationreaction rate was studied. Incorporation of PEG-BAE into phenolic(PF) foams leads to an improvement in the flexural and compressionstrengths, and a reduced pulverization ratio compared with pure andPEG-toughened foams. The LOI results illustrate the flame-retardingeffect of PEG-BAE is better than that of pure PEG, with LOI in therange 35.5–39.0%, and all PF foams pass UL 94 V-0 rating. Conecalorimeter results indicate that the incorporation of PEG400 increasesthe peak heat-release rate (PHRR) of PF foam by 38%, whereas PEG400-BAEresults in a slightly decreased PHRR. Moreover, thermal decompositionof pure and toughened PF foams was investigated. [ABSTRACT FROM AUTHOR]

Typical sulfur-containing amino acids, cysteine and methionine, were employed as stabilizers in place of lead(II) acetate in the electroless nickel plating (ENP) system. Each of these compounds presents a critical stabilizing concentration of ca. 10 −5mol/L, below which the ENP rate is slightly promoted with increasing concentration but above which it is significantly suppressed. Their role in stabilizing the ENP bath was found to involve inhibition of the anodic reaction of hypophosphite. The chemical adsorption of these two amino acids on active nickel sites at the Ni plating surface was studied via their adsorption on an in situ generated Ni powder. In addition, the stabilization mechanism was investigated by using potentiometry, X-ray photoelectron spectroscopy (XPS), and UV−vis/infrared spectroscopy. Finally, the bath stabilizing capabilities of these two amino acids and the change in ENP properties with time were assessed through a continuous operation comprising four metal-turnover (MTO) runs. [ABSTRACT FROM AUTHOR]

A simplified activity model was developed based on the nonrandom version of statistical thermodynamics. The partition function consists of two parts:  one is a random distribution of the empty sites, which corresponds to the ideal solution part, and the other is a correction factor for the actual nonrandom distribution of the empty sites, which corresponds to the excess part. Model parameters are not difficult to obtain in comparison with other model equations. The applicability of this model was demonstrated by calculating the solvent activities in 12 polymer solutions. It is found that the calculated results are consistent with the experimental data. The present model was also applied to describe the phase diagram of polystyrene−cyclohexane and polystyrene−ethyl acetate. It is proved that the method was able to correlate both low critical solution temperature and upper critical solution temperature. Furthermore, extension of this model equation to multicomponent systems is straightforward, so the present model can be taken as an alternative for the description of the phase behaviors in polymer solutions. [ABSTRACT FROM AUTHOR]

Novel organic−inorganic hybrid membranes were prepared through sol−gel reaction of poly(vinyl alcohol) (PVA) with -aminopropyl-triethoxysilane (APTEOS). The membranes were characterized by FT−IR, solid-state NMR, WXRD, SEM, and contact angle meter. The swelling degree of the hybrid membranes in an aqueous isopropanol (IPA) solution has been controlled owing to the formation of hydrogen and covalent bonds in the membrane matrix. The effect of APTEOS content in the membrane, feed flow, feed concentration, and temperature on pervaporation (PV) performance was investigated. The water permselectivity increased, and permeation flux increased quickly with increasing APTEOS content when it was less than 5 wt %. The membrane containing 5 wt % of APTEOS has the highest separation factor of 1580 with a permeation flux of 26.5 × 10-3kg·m-2·h-1at 30 °C in PV separation of 90 wt % IPA in water. The temperature dependence of permeation flux can be described by an Arrhenius-type relationship. [ABSTRACT FROM AUTHOR]

Phosphine (R3P) compounds being a typical type of coordination ligand used in homogeneous catalysis are known to possess a tunable affinity with the nickel atom. As such, it deserves to be studied whether a water-soluble phosphine ligand could also be used as a plating stabilizer in the electroless nickel plating (ENP) system in place of hazardous Pb(II) salt and what will be the unique effects generated due to this replacement. Triphenylphosphine-3,3′,3′′-trisulfonic acid trisodium salt (TPPTS) was then chosen as a model phosphine stabilizer to perform the study. TPPTS could indeed work to prevent the ENP process from running out of control. In addition, unlike the existing ENP stabilizers, TPPTS does not reveal a percolation concentration for a sharp ceasing of plating. Also according to the voltammetry investigation, TPPTS can be classified as a cathodic stabilizer. A Ni−P plating layer with high phosphorus content (>15%) has been achieved using10−4mol/L TPPTS in the plating bath. Furthermore, this work investigated the relation between P weight percent and corrosion resistance of either the as-plated or the annealed Ni−P plating layer by electrochemical impedance spectroscopy (EIS). The annealing was found, according to the depth profile analysis, to drive diffusion of both Ni and P toward the bulk phase, which strongly revamps corrosion resistance of the plating layer. Finally, the stability of the ENP bath was evaluated using the metal-turnover (MTO) test. [ABSTRACT FROM AUTHOR]

A tubular condenser column was designed and constructed to evaluate the performances of the condensation process with a high fractional noncondensable gas in the dewvaporation desalination process. An experimental investigation has been conducted to determine the local condensation heat transfer coefficient, which is related to steam−air mixed gas condensation in an annulus around a vertical copper tube. The results show that the local heat transfer coefficient decreases with increase of the distance from the mixed gas inlet, and varies from 200 to 1900 W/m2·°C, which is high enough for steam condensation in the presence of a high fractional noncondensable gas. The correlation of steam condensing local heat transfer coefficient in the presence of a high fractional noncondensable gas was developed in terms of the local mixture Reynolds number, Jakob number, and ratio of noncondensable gas mass fraction. It is found that the correlation has a good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Multiresponsive composite microspheres were fabricated via emulsion polymerization in two steps. Fe 3O 4nanoparticles modified by oleic acid (about 13 nm in diameter) were first prepared, and then they were embedded in biocompatible chitosan (CS) and N-isopropylacrylamide (NIPAm). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) examined the structure and morphology of the composite microspheres. Scanning electron microscopy (SEM) and transmission electronic microscopy (TEM) indicate the diameter of the composite microspheres to be about 400 nm. The magnetic, thermo, and pH-sensitive properties of the composite microspheres were investigated. Magnetic measurements with magnet and superconducting quantum interference device (SQUID) reveal that the composite microspheres are superparamagnetic. The electromagnetically induced heating shows that the composite microspheres could be heated up to 45 °C in an alternating electromagnetic field. The dynamic light scattering (DLS) results confirm the thermoresponsive and pH-responsive properties. It was found that the lower critical solution temperature (LCST) of the composite microspheres is 29 °C in water, and the LCST changed from 28 to 32 °C in the pH range from 4.7 to 7.4. These composite microspheres with the multiresponsive properties show great promise in biomedical applications. [ABSTRACT FROM AUTHOR]