不饱和聚酯树脂的乳化

讨论了不同种类的醇对磺酸盐不饱和聚酯树脂微乳液的粘度和电导率的影响 ,研究了醇的极性和含量 ;水和磺酸盐含量对形成微乳液的影响。结果表明 :聚酯磺酸盐的分子链易形成一种微离子网络 ,而自乳化过程是由微离子网络的溶解和疏水链段聚集构成的。     

The study on the conductivity of styrene-maleic anhydride copolymer electrolytes based on poly(ethylene glycol)400 and LiClO4

Polyelectrolytes, in this study were synthesized from styrene-maleic anhydride (SMA) copolymer, poly(ethylene glycol)400 (PEG400), and lithium perchlorate (LiClO₄). Fourier transform infrared spectroscopy (FTIR), and magic angle spinning (MAS) solid-state NMR were used to monitor the interaction between Li⁺ ions and polymer. The results of FTIR and MAS solid-state NMR indicate the Li⁺ ions are preferentially coordinated to the ether oxygen of PEG. The T_g of the PEG segments in polyelectrolyte increases with LiClO₄ concentration, as determined by differential scanning calorimetry (DSC), indicating that solubility of the Li⁺ ions in the host polymer increases with the PEG content. Impedance spectroscopy (IS) shows that the bulk conductivity of polyelectrolytes and the conductivity behavior obeys the Vogel-Tamman-Fulcher (VTF) equation.     

Dielectric properties of concrete and their influence on radar testing

Sub-surface radar is becoming increasingly popular as an inspection method. Interpretation can be enhanced if uncertainties about the dielectric properties of the concretes under investigation are removed. The need for reliable data to identify possible variations of the dielectric properties of different concrete mixes and their condition on site has led to a systematic laboratory based experimental programme under the auspices of a major European Commission (Brite-Euram III Framework 4) funded project. Some key results from this recently completed work are presented in this paper with practical implications related to field surveys of structural concrete.     

Effect of Soluble Solids Concentration and Temperature on Thermo-Physical and Rheological Properties of Mango Puree

Thermo-physical and rheological properties of mango pulp were evaluated at different temperatures (20, 40, 60, and 80°C) and total soluble solids concentrations (15, 20, 32, and 40°Brix). Thermal properties were primarily dependent on the moisture content of the sample, and increased with temperature and decreased with soluble solids concentrations. Density showed a reverse trend. Glass transition temperatures increased with an increase in soluble solids concentrations indicating better stability. Empirical models developed for each thermal property as a function of temperature and soluble solids concentrations (R² > 0.90) generally showed better predictions than published models. Mango puree exhibited pseudo-plastic behavior during steady shear measurements, and the power law model well described their flow behavior. Consistency coefficient increased with soluble solids concentrations and decreased with temperature. The flow behavior index ranged between 0.27 and 0.38 but did not show a clear trend either with soluble solids concentrations or temperature. Small amplitude oscillatory shear measurements revealed that mango puree behaved like a weak gel and demonstrated visco-elastic properties.     

Perfluorinated nanocomposite membranes modified by polyaniline: Electrotransport phenomena and morphology

This work summarizes results on the modification of perfluorinated sulfocationic membranes MF-4SC by in situ chemical polymerization of aniline. The investigation of transport properties of polyaniline/MF-4SC composite membranes after bulk modification - conductivity, diffusion and electroosmotic permeability, proton permselectivity - as well as porosimetry and polarization behavior is carried out as functions of aniline polymerization parameters and acid concentration. The fibrous-cluster model of a composite membrane is proposed for the estimation of transport and structural parameters, taking into account different mechanism of charge transfer in structural fragments of the composite. The atomic force microscopy images and curves of water distribution on the effective pore radii in the composite membranes testify to a morphological transition from the nano- to the microsize of polyaniline inclusions with increasing the aniline polymerization time. This effect is confirmed by the analysis of two-phase model transport and structural parameters. High values of the “true” proton transport numbers of composites are obtained and discussed. The dynamic hydration numbers of protons and chloride co-ions are estimated using the “true” transport numbers of protons and the electroosmotic coefficients of composites. The current-voltage curves of composite membranes in the “free standing” state after bulk and surface modification by polyaniline are investigated. The effect of stabilization of limiting current density is observed for MF-4SC membrane after bulk modification. The effect of current-voltage curves asymmetry is observed for different orientation of the polyaniline layer towards the current direction for an anisotropic composite membrane after surface modification.     

应用电导探针法测定气泡参数

采用照相法对研制的双电导探针测定气泡参数的测量系统■进行标定,并将其用于测定槽径为(?)0.287m 的搅拌槽内的气泡运动速度、气泡大小分布。     

The effect of multiple doping on electrical conductivity of gadolinia-doped ceria electrolyte

Combinations of two or four trivalent oxides were substituted for gadolinia up to 5 mol% in the 20 mol% gadolinia-doped ceria electrolyte as additional dopants. Most of them increased the electrical conductivity of the electrolyte but some did not. Among them (YLa)_0.01Gd_0.19Ce_0.8O_1.9 and (YSm)_0.03Gd_0.17Ce_0.8O_1.9 showed the highest electrical conductivities, respectively, at 800 ‡C and 600 ‡C. These experimental results were analyzed in terms of activation enthalpy and entropy for ionic conduction. Among the various possible contributions to the activation entropy, only the configurational entropy was taken into account for the explanation.     

Characterization of solid polymer electrolytes based on poly(trimethylenecarbonate) and lithium tetrafluoroborate

The results of an investigation of a polymer electrolyte system based on the poly(trimethylene carbonate) host matrix, designated as p(TMC), with lithium tetrafluoroborate guest salt are described in this presentation. Electrolytes with lithium salt compositions with n between 3 and 80 (where n represents the number of (OCOCH₂CH₂CH₂O) units per lithium ion) were prepared by co-dissolution of salt and polymer in anhydrous tetrahydrofuran. The homogeneous solutions obtained by this procedure were evaporated, within a preparative glovebox and under a dry argon atmosphere, to form thin films of electrolyte.The solvent-free electrolyte films produced were obtained as very flexible, transparent, completely amorphous films and were characterized by measurements of total ionic conductivity, cyclic voltammetry, differential scanning calorimetry and thermogravimetry.     

Research information: A model of radiant floor thermal behaviour

A model of an industrial radiant floor's thermal behaviour is considered through a formula based on the finite elements method. The objective is to establish the theoretical bases and computing tools to optimize the heating system. Montse Sanchez-Romero and Pere Alavedra-Ribot continue previous published work (BRI, 25(6), 369-73). 'Experimental study of the thermal behaviour of radiant floors'.     

Electrical conductivity and charge compensation in Ta doped Li4Ti5O12

Ta doping in Li₄Ti₅O₁₂ (Li₄Ti_4.95Ta_0.05O₁₂) as function of different heat-treat atmospheres (oxidizing/reducing) was investigated and compared to Li₄Ti₅O₁₂ to determine its effect on ionic/electronic conductivity and the charge compensating defects. Under oxidizing conditions Li₄Ti_4.95Ta_0.05O₁₂ was primarily an ionic conductor where the extra charge of Ta was compensated by Ti vacancies. Under reducing conditions Li₄Ti_4.95Ta_0.05O₁₂ was primarily an electronic conductor where the extra charge of Ta was compensated by an electron. The charge compensating defects were confirmed by sintering data.