Effect of the core-shell latex polymer content on the compatibility, morphology and mechanical properties of PC/PBA-cs-PMMA blends

The toughening effect of the content of a core-shell poly(butyl acrylate)/poly(methyl methacrylate) latex polymer (PBA-cs-PMMA) on the mechanical properties, morphology and compatibility of its blends with polycarbonate(PC), i.e., PC/PBA-cs-PMMa, was studied. The mechanical properties of the blends are strongly affected by varying the content of PBA-cs-PMMA in the blend. When the PBA-cs-PMMA content is only 5 wt.-%, the impact strength of PC/PBA-cs-PMMA is almost 19 times as high as that of pure PC, indicating that PBA-cs-PMMA is a very good impact modifier for PC. With increasing interphacial layer thickness and decreasing interphacial tension, the interphacial activity becomes more and more effective and, at the same time, miscibility increases too.

A study on the diffusion of quinhydrone in polymer electrolyte

The diffusion coefficients (D) of quinhydrone were estimated in polymer electrolytes by using non-steady-state chronoamperometry and steady-state current voltammetry. The D values have been estimated in polyethylene glycol (PEG) containing different concentrations, and cations of supporting electrolytes, and in different solvents over a range of temperatures. The dependencies of electroactive probe diffusion coefficients on temperature, supporting electrolyte concentration and polymer chain length are discussed. The results show that D increases with increasing temperature and decreasing concentration of supporting electrolyte. The diffusion coefficient depends strongly on the length of polymer chain and decreases sharply with increasing polymer chain length. The contribution of electron self-exchange has been explored and it seems to be negligible here. (C) 1998 Elsevier Science S.A.

Studies of ferrocene derivative diffusion and heterogeneous kinetics in polymer electrolyte by using microelectrode voltammetry

The heterogeneous electron transfer rate constants (k(s)) of seven ferrocene derivatives were estimated using cyclic voltammograms under mixed spherical/semi-infinite linear diffusion and steady-state voltammetry at a microdisk electrode in polymer electrolyte. The k(s) and diffusion coefficient (D) are both 100 to 1000-fold smaller in polymer solvent than in monomeric solvents, and the D and k(s) decrease with increasing polymer chain length. The results conform to the difference of viscosity (eta) or relaxation time (tau(L)) for these different solvents. The k(s) and D increase with increasing temperature, and the activation barriers of the electrode reaction are obtained. The influences of the substituting group in the ferrocene ring on k(s) and D are discussed. The k(s) are proportional to the D of the ferrocene derivatives, which indicates that solvent dynamics control the electrode reaction. (C) 1998 Elsevier Science S.A.

Thermal, mechanical and ionic conductive behaviour of gamma-radiation induced PEO/PVDF(SIN)-LiClO4 polymer electrolyte system

An effort has been made to modify the mechanical behaviour of our previously reported gel-type gamma-radiation crosslinked polyethylene oxide (PEO)-LiClO4 polymer electrolyte. A highly polar and gamma-radiation crosslinkable crystalline polymer, polyvinylidene fluoride (PVDF), was selected to blend with PEO and then subjected to gamma-irradiation in order to make an simultaneous interpenetrating network (SIN), which was used as a polymer host to impart stiffness to the plasticized system. Experimental results have shown that the presence of PVDF in the system, through gamma-radiation induced SIN formation, could not only give a rather high mechanical modulus of 10(7) Pa at ambient temperature, but also maintain the room temperature ionic conductivity at a high level (greater than 10(-4) S/cm). DSC, DMA and conductivity measurement techniques were used to examine the effects of blending, gamma-irradiation and plasticization on the variations of glass transition and melting endotherm, on the appearance of high elastic plateau and on the temperature dependence of ionic conductivity: In addition, it was found that, in contrast with the unplasticized system, the ionic conductivity mechanism of this gel-type electrolyte seems to conform to the Arrhenius model, suggesting that, as a result of the high degree of plasticization, the polymer chains act mainly as the skeleton of the networks or polymer cages to immobilize the liquid electrolyte solution, whereas the ionic species migrate as if they were in a liquid medium. (C) 1997 Elsevier Science Ltd.

A study of the dependence of ferrocene diffusion on chain length in polymer electrolytes

The diffusion rates of ferrocene have been estimated in five kinds of poly(ethylene glycol) solution, containing the electrolyte LiClO4, by using non-steady-state chronoamperometry. The D-app of ferrocene increases with increasing temperature, and the dependency of D-app on temperature obeys the Williams-Landel-Ferry equation. The D-app of ferrocene decreases with increasing polymer chain length. Both the chain length and temperature dependence conform to a simple free volume model. A relation between current and polymer chain length is suggested at room and high temperatures.

A study of the dependence of ferrocene diffusion on electrolyte concentration and size in a polymer medium using non-steady-state chronoamperometry

This article describes a quantitative study of the diffusion rate of ferrocene(Fc) dissolved in ploy(ethylene glycol)(PEG) medium containing MClO(4)(M = Li+, Na+, Bu(4)N(+), Hx(4)N(+)). The apparent diffusion coefficient D-app and the active concentration c(a) of Fc were simultaneously measured by using non-steady-state chronoamperometry. The D-app and c(a) of Fc have been estimated in PEG containing different concentrations and sizes of supporting electrolyte, and the dependence of D-app on ferrocene concentrations has been observed. The values of D-app decrease with increasing concentrations of Fc, increasing concentrations of LiClO4 or the ratio (O:Li) and also with 4 decreasing cation radius of the electrolyte. The temperature dependencies conform to a simple free volume model. The concentration and size of the counterion dependencies of the diffusion rate are similar to the behavior of their dependencies of ionic conductivity in polyelectrolyte.

A STUDY ON POLYMER-POLYMER INTERACTIONS THROUGH MIXING CALORIMETRY

The aim of this work is to describe the most recent achievements in the field of the physical chemistry of mixing. The systems studied have been classified according to the amount of thermic effect due to the blending and its interpretation. When polystyrene (PS) and poly(alpha-methylstyrene) (P alpha MS) are blended, the interaction is weak and Delta(mix)H is close to zero. The presence of polar atoms and/or groups increases the stability of the blend and, therefore, Delta(mix)H becomes more negative. Poly(ethylene oxide) (PEO), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA) and poly(vinylacetate) (PVAc), when mixed to form binary systems, show large differences from their properties when pure. If hydrogen bonding takes place, the interactions are readily detected and a large effect is calorimetrically determined. Cellulose diacetate (CDA) and poly(vinylpyrrolidone) (PVP) have been studied as an example of a strongly interacting system.

STUDY ON MASS-TRANSPORT IN EASTMAN-AQ POLYMER FILM BY USING NON-STEADY-STATE CHRONOAMPEROMETRY AT AN ULTRAMICRODISK ELECTRODE

Non-steady-state chronoamperometry of ultramicroelectrodes is a powerful method for the study of mass transport in polymer films. This method has many advantages over the conventional methods at a macroelectrode and the steady state method at an ultramicroelectrode, which yield the most information. The apparent diffusion coefficient, D(app), and the concentration of reactant in the film, c(f), can be determined from a single experiment without knowing the thickness of the film. We studied the transport of several species such as Ru(NH3)63+, Ru(bpy)3(2+), NR and MV2+ in Eastman-AQ polymer film coated ultramicroelectrodes by using this method.

STUDY ON OPTICAL-ROTATORY OF HELIX POLYMER POLY(TRIPHENYLMETHYL METHACRYLATE)

The optical rotatory of helix polymer poly(triphenylmethyl methacrylate) (PTrMA) has been studied. The specific rotation of PTrMA is related with the length of helical chain linearly, while P(n)BAR<6 and P(n)BAR greater-than-or-equal-to 15. When P(n)BAR greater-than-or-equal-to 15, [alpha]D/20 = 1.6 P(n)BAR + 290-degrees. The contribution of each repeating unit to [alpha]D/20 is 1.6-degrees. In the 300-600 nm region, the ORD of PTrMA obeys both the Drude equation and Moffitt equation. The relationship between the [alpha]D of PTrMA and the solvent, concentration and temperature has also been investigated.

CONFORMATION OF PHENYL RINGS IN THE HELICAL CHAIN POLYMER POLY(TRIPHENYLMETHYL METHACRYLATE)

The conformation of phenyl rings in the side groups of the helical chain polymer poly(tripenyl-methyl methacrylate) (1) in solution was studied by spectroscopic methods. According to the Raman spectrum the phenyl rings of 1 and triphenylmethyl methacrylate in solution have the same depolarization ratio at 1002 cm-1. The electronic spectra (ultraviolet and fluorescence) of 1 are similar to those of model substances, except for the "red shift" of the spectra of about 5 nm. It was concluded that the phenyl rings can rotate around the phenyl-C bond.

ADVANCED ELECTROANALYTICAL CHEMISTRY IN CHINA .1. GENERAL ASPECT AND SOME METHODOLOGIES

The Research on Electroanalytical chemistry in China started mainly from the beginning of new China in 1949. It has already good basis and development nowadays. A review with references to the end of seventies has been published in "Reviews in Analytical Chemistry" 1) and in a book titled "Fifty years of Chinese Chemistry" edited by the Chinese Chemical Society in 1985 2). Since then more than thousand papers have been published, and it is impossible and also not necessary to describe all of them. This review only deals with the main progress of electroanalytical chemistry in China in recent years. Some new developed methodologies will be reviewed by S. Dong in the next article.

FACTOR-ANALYSIS APPLIED TO X-RAY-DIFFRACTION DIAGRAMS OF POLYMER BLENDS

The feasibility of applying the method of factor analysis to X-ray diffraction diagrams of binary blends of polypropylene and ethylene-propylene-diene terpolymer (PP/EPDM) was examined. The result of mathematical treatment was satisfactory. The number of scattering species and their concentrations in six kinds of PP/EPDM blends were determined. The separation of the spectral peaks of each species in the blends, contributing spectral intensities, was carried out.

CHARACTERIZATION OF GAMMA-IRRADIATED CRYSTALLINE POLYMER .3. THERMAL-BEHAVIOR OF GAMMA-IRRADIATED POLYAMIDE-1010

Thermal behaviour of gamma-irradiated plain PA1010 and PA1010 containing different amounts of difunctional cross-linking agent BMI was investigated. In DSC endo- and exotherm, it was found that during irradiation, the presence of BMI markedly changes the melting and crystallisation characteristics of PA1010. A supposition that the network of BMI-containing specimens is rather loose in structure was proposed to explain the discrepancy in thermal behaviour between these two kinds of specimens. The supposition was further ascertained by the less brittleness in mechanical property of specimens containing BMI. Besides, the complexity of the thermal behaviour of gamma-irradiated PA1010 was discussed and attributed mainly to the increase in sigma-e, the fold surface free energy of chain fold crystals.

RELATIONSHIP OF THE SEQUENCE DISTRIBUTION OF A POLYMER TO THE CATALYTIC ACTIVITY OF ITS ND COMPLEX

The sequence distribution of the monomeric units in the styrene-acrylic acid copolymer has been obtained by calculation. The probability of long sequences of styrene increases with an increase in the content of the monomer in the copolymer. The highest distribution of short sequences of styrene takes place for the copolymer containing equimolecular amounts of styrene and acrylic acid. The copolymer which has this latter structure is inadequate for the synthesis of highly active supported complexes. When the distributions of long and short sequences of styrene are approximately equal, the activity of the Nd and Fe prepared polymer complexes is higher.