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Polyethylene glycol borate (PEG-BAE) toughening agents were prepared from the esterification reaction between boric acid and PEG and characterized by FTIR and NMR. The effect of reaction conditions such as reaction temperatures, reaction times, and entrainer amounts on the esterification reaction rate was studied. Incorporation of PEG-BAE into phenolic (PF) foams leads to an improvement in the flexural and compression strengths, and a reduced pulverization ratio compared with pure and PEG-toughened foams. The LOI results illustrate the flame-retarding effect of PEG-BAE is better than that of pure PEG, with LOI in the range 35.5–39.0%, and all PF foams pass UL 94 V-0 rating. Cone calorimeter results indicate that the incorporation of PEG400 increases the peak heat-release rate (PHRR) of PF foam by 38%, whereas PEG400-BAE results in a slightly decreased PHRR. Moreover, thermal decomposition of pure and toughened PF foams was investigated.

Mesoporous polymer membranes are important in various separation processes and have become more crucial with increasing concerns in environment protection. Here, we report novel mesoporous membranes of polyvinyl chloride (PVC) nanofibers prepared via a modified freeze-extraction technique. The as-prepared nanofibers have an average diameter of ∼45 nm and are dispersed heterogeneously in an ethanol solution. The nanofiber formation is studied in detail. The resulting nanofiber dispersion is directly filtered on a macroporous support to fabricate mesoporous membranes. The as-fabricated membranes have a controllable thickness ranging from 360 nm to 1055 nm, and a high porosity up to 63% that is at least 5 times greater than that of most of the commercial ultrafiltration membranes. These membranes present an ultrahigh water flux up to 6612 L m–2 h–1 bar–1 and a good ferritin rejection during ultrafiltration. Moreover, these membranes show a fast and high-efficient absorption for Methylene Blue (MB). The newly...

A new H3PW12O40 (PW12)-based interfacial layer for dye-sensitized solar cells (DSSCs) has been fabricated by the LBL method. The features of the interfacial layer were tested by IR and UV–vis spectroscopies and AFM. The cells were systemically tested by the photocurrent–voltage (J–V) curve, dark-current measurement, open-circuit voltage decay (OCVD), and monochromatic incident photon-to-photocurrent conversion efficiency (IPCE) techniques. The PW12-based interfacial layer was found to accelerate electron transfer and retard recombination, eventually leading to an efficient increase in energy conversion efficiency. The investigations indicate that the energy conversion efficiency of a (PW12/TiO2)3-based DSSC is significantly enhanced by 54% at 100 mW cm–2 compared with a DSSC with no treatment and by 20% compared with a TiCl4-treatment DSSC. Polyoxometalate was first introduced into the interfacial layer in modifying the photoanode to accelerate electron transfer and retard recombination to improve DSSC ef...

National Natural Science Foundation of China [21107089]; Nature Science Foundation of Fujian Province of China [2011J01055]; research fund for the Doctoral Program of Higher Education [20110121120041]

National Nature Science Foundation of China [21076170, 21107089]; research fund for the Doctoral Program of Higher Education [20110121120041, 20120121120013]; Fundamental Research Funds for the Central Universities [2012121029]

Random packing of particles has served as a topic of intense research in the chemical, physical, engineering, and material fields. The majority of previous works focused on the random packing models of spherical, cylindrical, and ellipsoidal particles, whereas little is known about polyhedral particles. In this article, a modeling study of the random packing of convex polyhedral particles is presented in detail, using an interparticle contact detection algorithm, a particle-to-container wall intersection detection algorithm, and a random sequential packing algorithm for hard particles, and the accuracy and efficiency of the contact detection algorithm are compared with those of methods from the literature. With the random packing model and a specified particle size distribution, mesostructure models of particulate composites with mono-/polydisperse particles were generated and validated by a sectioning analysis algorithm. Based on quantitative stereological theories and the sectioning analysis algorithm, the effects of particle shape on the mesostructures composed of the monodisperse and polydisperse particles were evaluated. Further, the statistical results were verified by validation against experimental results from the literature and theoretical results.

A polyoxometalate (POM)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) hybrid film counter electrode was successfully fabricated by electropolymerization in an environmentally friendly aqueous solution. The hybrid film presents a similar surface morphology to lotus leaf, the microstructure of which is a regularly distribution of mastoid shapes. As far as we know, it is the first time that POM-PEDOT hybrid film with mastoid morphology was fabricated. The application of the hybrid film counter electrodes (CEs) in dye-sensitized solar cells (DSSCs) was studied for the first time, and the efficiency of DSSCs based on hybrid film CEs was almost as high as DSSCs with Pt CEs. FTIR results indicated that POM polyanions had already been dispersed into the PEDOT matrix. Cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization test results show that the electrocatalytic ability for I3– reduction of the hybrid film CE is comparable to that of a Pt CE. In addition, the SiW11–PEDOT hybrid film...

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 ...

National Nature Science Foundation of China [50573063]; Program for New Century Excellent Talents in University ; Doctoral Program of Higher Education [2005038401]; Xiamen University [0000X071C1]

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. 10−5 mol/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.

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 presen...

Novel organic−inorganic hybrid membranes were prepared through sol−gel reaction of poly(vinyl alcohol) (PVA) with γ-aminopropyl-triethoxysilane (APTEOS). The membranes were characterized by FT−IR, ...

A simplified activity model for polymer solutions is derived from the Gibbs−Helmholtz relation, in conjunction with the lattice theory in this work. The model includes not only combinatorial and residual terms but also a free-volume (FV) term. The calculated results differ significantly between the model equations with and without taking the FV effect into consideration. The validity of this new method is demonstrated by comparing the calculated activities from the proposed model equation with those by the Entropic-FV (EFV), UNIFAC-FV, and UNIFAC methods. The overall average absolute deviation (AAD) of solvent activities in 34 polymer solutions was 7.58% for the EFV method, 5.32% for the UNIFAC-FV method, 22.00% for the UNIFAC method, and 3.48% for the proposed model. It is shown that the new model can yield improved results over the other models and is able to predict the phase behavior for polymer solutions over a wide range of molecular weights, temperatures, and densities.

A new tray, the 95 tray, was designed on the basis of numerical calculations. A pilot-scale setup was established to evaluate the hydrodynamic properties of the 95 tray. Experimental data on the flow patterns, pressure drop, weeping, and downcomer liquid backup were obtained and analyzed, and the equations for calculating the tray pressure drop and downcomer backup were thus derived. The flow pattern for the 95 tray is nearly in an ideal mode if suitable deflectors are set. The per tray pressure drop for the 95 tray is approximately one-half of that for a conventional sieve tray in the range of medium to high vapor flow rates, and the divergence of the per tray pressure drop between the two kinds of trays is increased with increasing vapor flow rate. It is demonstrated that the 95 tray can offer the advantages of a lower pressure drop and a larger capacity. The weeping curve for the 95 tray is found to be a little lower than that for the conventional tray.