Diffusion of some dyes in aqueous polymer solutions

The diffusion of both Direct Blue 76 and acid orange dyes in aqueous dilute polymer solutions was studied using the capillary method. The polymer systems studied included dilute solutions of carboxymethyl cellulose, polyethylene oxide and polyacrylamide. It was found that the diffusion coefficients of the two dyestuffs in carboxymethyl cellulose solutions are higher than that in pure water, while in polyacrylamide solutions the values of the coefficients are lower than that in pure water. In case of polyethylene oxide solutions, the diffusion coefficient of Direct Blue 76 was found to be lower than that in pure water, whereas that of acid orange was found to be higher than that in pure water. The diffusion coefficients of both dyes were found to decrease with increasing polymer concentration in the case of polyethylene oxide and polyacrylamide, whereas in the case of carboxymethyl cellulose the diffusion coefficients increased with polymer concentration. With change of temperature, the diffusion coefficients of both dyes in the three polymer solutions were found to obey the Arrhenius equation. The activation energy for diffusion of the two dyes was calculated in pure water, as well as in the different polymer solutions.     

Wetting kinetics of polymer solutions and force‐based contact angles

The effect of the shear thinning behavior and elasticity of polymer solutions on the dynamic contact angles are investigated. Under dynamic conditions, the contact angle of a liquid on a solid surface changes significantly with the substrate velocity from its equilibrium value. The dynamic contact angles for polyethylene oxide (PEO) solutions of two molecular weights 3 × 10⁵ and 4 × 10⁶ have been measured using a polyethylene terephthalate (PET) plate. The three‐parameter Ellis model to fit the rheological data to obtain shear thinning power n, characteristic shear stress, and the zero‐shear viscosity is used. The theory indicates that dynamic contact angles follow power law in this instance instead of showing Newtonian behavior with zero‐shear viscosity when the shear thinning effects are considered. The elastic effect becomes important at larger polymer concentrations that reduces the dependence on capillary number, that is, reduces n keeping with the experiments. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2533–2541, 2016     

Glassy polymer solutions: some morphology—property relationships

The in-situ crystallization of low molecular weight crystalline organic compounds in general purpose and high impact polystyrene has been studied. Three modes of crystallization, namely needle-like, dendritic and tiny crystalline particles have been observed in these systems. Phase diagrams of tetrachloroxylene and tetrachlorobenzene with high impact polystyrene have been constructed. The effects of the crystalline additive, its concentration and morphology on some mechanical properties have been analysed. A significant difference between general purpose and high impact polystyrene was observed regarding their mechanical behaviour in the presence of the crystalline additives. Exudation and crystallization of the crystalline additives on the surface are also discussed. It is shown that these phenomena can be enhanced by annealing and stress crazing.     

生物降解性高分子材料(续)

本文综述了国内外生物降解高分子材料的研究现状和发展方向，分析了国内外生物降解研究和生产中存在的几个问题，结合我国的国情，对我国未来生物降解高分子的研究和发展提出了几点建议。     

生物降解性高分子材料

本文综述了国内外生物降解高分子材料的研究现状和发展方向，分析了国内外生物降解研究和生产中存在的几个问题，结合我国的国情，对我国未来生物降解高分子的研究和发展提出了几点建议。     

The reaction between hydrazine and oxygen in water

Studies of the reaction between hydrazine and oxygen at 25° and 70° in alkaline solution have shown that the observed rate is due to catalysis by traces of impurities. It has been found that copper(II) and manganese (II) are the most active catalysts, and, under certain conditions, the copper(II)-catalysed reaction appears to be homogeneous. Evidence is presented that catalysis occurs by redox reactions. The copper(II)-catalysed reaction has been studied in some detail, but only the earlier stages fit a simple kinetic equation.     

Connectivity and spacing effects in hydrogen-bonding polymer solutions and blends

In recent experimental work, it was found that the number of hydrogen bonds in polymer mixtures is strongly influenced by chain-connectivity effects and the spacing of functional groups along the chain. In this article, the relationships between the equilibrium constants used to describe the number of hydrogen bonds in mixtures of various types (blends, solutions, random copolymers, etc.) is elucidated and described. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1273–1281, 1998     

The behaviour of bubbles in polymer solutions

By using a model of power-law fluid as polymer solutions, the equation which gives the maximum impulse pressure occurring during the bubble collapse is obtained. By the numerical analyses, the effects of the initial bubble radius, the polymer concentration, and the pressure ratio of inside and outside the bubble, etc. on the bubble behaviour are clarified, and the relations between the time elapsed and the pressure or the velocity at the bubble wall and the values of the maximum impulse pressure are obtained. Then, these results in polymer solutions are compared with those in Newtonian fluid (water).     

智能高分子与高分子凝胶

简述智能高分子材料，并进行了详细分类。从合成及其加工设备、新产品开发、设计方案、应用前景等诸方面详细的阐述了智能高分子凝胶。     

Heat transfer to polymer solutions and melts flowing between parallel plates

Heat transfer to polymer solutions or melts flowing in parallel plate systems is an important aspect of polymer processing as for example in extrusion through a wide slit. The present work solves the equation of energy for pseudoplastic non-Newtonian fluids flowing between parallel plates. An exact velocity profile rather than an approximation is used. Equations are derived both for temperature profiles and mean temperatures. The results are shown to correctly represent the physical situation.     

Structures and interactions between two colloidal particles in adsorptive polymer solutions

The role of weak adsorptive polymer chains in the colloidal particles solution is studied by self-consistent field theory (SCFT). The numerical results show the potential between colloids are attractive interaction. Besides the depletion effects the chain conformations such as loop, tail and bridge between two spherical colloidal particles play important roles. The quantitative polymer concentration dependent chain conformations and then the effective potential are also addressed.     

Miscibility and interaction studies on some aqueous polymer blend solutions by ultrasonic and rheological techniques

The aqueous solutions of poly(ethylene oxide)–polyacrylic acid, poly(vinyl pyrrolidone)–poly(vinyl alcohol), and poly(ethylene oxide)–poly(vinyl alcohol) blends have been studied by ultrasonic, rheological, and viscometric techniques. Extensive investigation over a wide range of concentrations, temperatures, compositions, pH, and shear rates indicate the degree of miscibility, extent of interaction between the polymers, and stoichiometry of the polymer complexes formed by the strong interaction between the polymers in solutions. These investigations indicate the miscibility of poly(ethylene oxide)–polyacrylic acid and poly(ethylene oxide)–poly(vinyl pyrrolidone) blends and the immiscibility of poly(ethylene oxide)–poly(vinyl alcohol) blends in conformity with other reported investigations. © 1994 John Wiley & Sons, Inc.     

Effect of elastomeric additives on fabrication and properties of filled fiber materials formed from polymer solutions

We have studied the effect of elastomer additives on the properties of spin dopes for obtaining filled fiber materials by aerodynamic spinning from polymer solutions. We have obtained laboratory samples of materials with different polyurethane content. We have analyzed the results of physicomechanical, sorption, and physical tests of these materials. We show that modification of filled fiber materials by introducing elastomeric additives has only an insignificant negative impact on the sorption properties and markedly improves their physicomechanical characteristics.     

The falling laminar jet of semi-dilute polymer solutions

The studies of falling laminar jets have been done mainly on Newtonian jet due to the complexity of non-Newtonian fluid parameter. Numerical solutions of the Newtonian jet equation are in good agreement with the experimental results of polymer solutions in the experimental concentration range. Numerical simulation results suggest that the free falling jet is mostly influenced by the Froude number. The jet radius increases with the Froude number. It was found that surface tension or viscosity does not contribute much to the shapes of the free falling jet.     

Differences in behavior between dilute and concentrated polymer solutions in elongational flow

In this paper, the different behavior of dilute and concentrated solutions (or melts) during an elongational flow is discussed. Some experimental results obtained with a concentrated polyacrylamide solution in water are presented together with a brief review of previous results relative to dilute solutions and melts. An interpretation of the data is attempted on the basis of well known concepts of macromolecular physics together with assumptions concerning the destruction and reformation of entanglements during the flow of the polymer.