RADICAL INITIATED COPOLYMERIZATION OF METHYL METHACRYLATE AND ACRYLONITRILE IN PRESENCE OF IRON COMPLEXES

This article represents data on the effect of organometallic iron complexes: ferrocene, dicarbonyl dimer of cyclopentadienyl iron and tricarbonyl cyclooctatetraene iron on the copolymerization of methyl methacrylate (MMA) and acrylonitrile (AN) initiated by benzoyl peroxide. It is shown that the introduction of metal complexes and their structure affect the initial rate of copolymerization, the form of the diagrams of the composition of the obtained copolymers, and the values of the effective constants of the relative activities of the comonomers in the copolymerization of methyl methacrylate and acrylonitrile (system metallocomplex of iron – peroxide benzoyl: ferrocene – peroxide benzoyl: rММА = 1.58; rАН= 0.08 in 60 °С; rММА = 1.30; rАН = 0.05 in 50 °С; dicarbonyl dimer cyclopentadienyl iron–peroxide benzoyl: rММА = 1.36; rАН = 0.06 in 60 °С; rММА = 1.09; rАН = 0.14 in 50 °С; tricarbonyl cyclooctatetraene iron -peroxide benzoyl: rММА = 1.08; rАН = 0.15 in 60 °С; rММА = 1.14; rАН = 0.05 in 50 °С; peroxide benzoyl: rММА = 1.11; rАН = 0.07 in 60 °С; rММА = 1.11; rАН = 0.07 in 50 °С). The proportions of triadic sequences of units in copolymers, experimentally determined from 1H NMR spectroscopy, are given, as well as the calculated proportions of dyads. The presence of iron metal complexes affects the distribution of the proportions of the triad and dyad sequences of units, as well as their microstructure in copolymers. These changes are explained by the formation of macromolecules, both with the participation of free radicals and the stereospecific coordination active centers of polymerization that are formed in the presence of iron complexes.

EFFECT OF HIGH-FREQUENCY ELECTROMAGNETIC FIELD ON THE MUTAROTATION OF AQUEOUS SOLU-TIONS OF GLUCOSE AND FRUCTOSE

The indirect influence of the high-frequency electromagnetic field of the 30–200 MHz low power range on the reaction rate of the mutation of D-glucose solutions and on the equilibrium in D-fructose and D-glucose solutions was studied. Solutions were prepared using both deionized water and water exposed to a high-frequency electromagnetic field. Control of the process of mutarotation was carried out polarimetrically. To assess the effectiveness of field exposure, the effective constants of the reaction rate of mutarotation were calculated. It has been established that the rate of mutarotation of D-glucose solutions non-linearly decreases with increasing frequency of the electromagnetic field. The effect of pretreatment of the solvent by an electromagnetic field on the equilibrium in solutions of fructose and glucose, which have been subjected to field exposure, has been studied. The observation was carried out for 30 days. It was found that the equilibrium specific rotation in the fructose solution as a result of the influence of the electromagnetic field shifts towards negative values, and in the case of glucose solution it does not change. An explanation of the results obtained is proposed, which is based on the assumption of a change in the structural organization of the solvent - water as a result of the high-frequency electromagnetic field, which can significantly change the hydration interactions of the reaction participants: carbohydrates and hydrogen ions.

Effective Anisotropy Constant of Bilayer Film

A reasonable composition of different kinds of magnetic anisotropy of bilayer film has been carried out. The criterium of magnetic uniaxiality of bilayer film contained the first-order and the second-order crystallographic anisotropy has been defined. It has been demonstrated that the effective constants of the first-order and the second-order magnetic anisotropy of bilayer film has a non-linear dependence on the corresponding constants of crystallographic anisotropy of the layers, angles between them and constants of interlayer exchange interaction.

SUBFACTORS OF INDEX LESS THAN 5, PART 4: VINES

We eliminate 39 infinite families of possible principal graphs as part of the classification of subfactors up to index 5. A number-theoretic result of Calegari–Morrison–Snyder, generalizing Asaeda–Yasuda, reduces each infinite family to a finite number of cases. We provide algorithms for computing the effective constants that are required for this result, and we obtain 28 possible principal graphs. The Ostrik d-number test and an algebraic integer test reduce this list to seven graphs in the index range (4,5) which actually occur as principal graphs.

Predicting the properties of micro- and nanocomposites: from the microwhiskers to the bristled nano-centipedes

The paper draws on the similarities between the well-known process of whiskerization of microfibres and the recent idea of bristled nanowires. The new method for evaluation of the effective elastic properties of such materials is suggested based on the model of four-component composition. This model assumes the transverse isotropy of continuum and predicts five elastic moduli and density as independent effective constants. An example of calculation of the constants for the particular materials is given. It shows the significant increase in the shear strength of composites with whiskerized or bristled fibres.

A Predicted Approach for Determining Effective Constants of Fiber Composite With Graded Interphase

A predicted approach for determining moduli, which include extensional moduli, shear moduli and Poisson’s ratio is presented for fiber composites with graded interphase. The approach is derived based on a mechanics of materials formulations for the concentric cylinder assembles model of a single fiber, surrounding matrix, and a graded interphase to account for the chemical reaction and diffuseness which commonly occurs between fiber and matrix. The principles of the displacement compatibility and force equilibrium for each constitutes of the representative volume element, converted to those of Equivalent Square assembles, are used in the process of the derived predicted approach without complicated computations. The validity of the predicted approach is demonstrated versus comparisons with experimental data and some other models existing in the literature. Synchronously, it shows that determining effective moduli of fiber composite with graded interphase by micromechanics equations is a special case of the predicted approach.