The effect of preferential solvation on the kinetic order of alkyl methacrylate polymerization in benzene

The kinetic order of the polymerization of n-alkylmethacrylates with respect to monomer in benzene (fractional and greater than one) has been interpreted as due to concentration changes of a monomer at the site of reaction caused by preferential solvation of the growing macromolecule by benzene. Correlation of the rates of polymerization at 30° with determined monomer concentrations in the close vicinity of the polymer chain gives kinetic orders of 1±0.05 for both n-butyl- and n-dodecyl-methacrylates. The coefficient of preferential solvation at 30° for the polymers investigated is between 0.1 and 0.4 [cm³ g^?1] depending on the composition of the mixture of benzene and monomer. The coordination numbers 3 and 4 needed for calculation of the composition of the solvent in the solvating layer correspond to theoretical views on polymer solutions.     

Beiträge zur Ringofenmethodik. V

Zusammenfassung Nach Abtrennung von Cu(II)-Ionen mit Hilfe der Ringofentechnik ist es möglich, Ultramikromengen Kupfer(II) mit 0,001-m ÄDTA gegen PAN als Indikator zu titrieren. Eine dazu geeignete Arbeitsweise wird angegeben.

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Contributions to the ring furnace methodology. V

Summary Following separation of the Cu(II) ions with the aid of the ring furnace technique, it is possible to titrate ultramicro amounts of copper(II) with 0.001M EDTA in the presence of PAN as indicator. A suitable procedure is given.

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IV. Teil: Mikrochim. Acta [Wien]1969, 25.     

Non-conservation of quasiparticles

An adequate canonical transformation of the hamiltonian permitted the full observance of the specific Pauli commutation relations and the elimination of the main quasiparticle non-conservative term. This will allow a correct treatment of the kinematic part of the interaction in many problems.     

An analytical approach to the distribution function of electrons in the molecular oxygen discharge

Analytical expressions for the electron distribution function and the kinetic coefficients in the molecular oxygen glow discharge are given. The relative importance of the various collisional processes in evaluation of some experimentally measured quantities is discussed as well as the validity of the present results.     

Absence of the second-order phase transitions in the dimerized Ising chains with spin larger than 12

A general spin S Ising chain interacting with a single phonon mode of the harmonic lattice is studied. The thermodynamics of the spin system is calculated exactly for S = 1, $\text{1}\text{2}$ and $\text{3}\text{2}$, while self-consistent equations for the induced lattice distortions are derived. It is demonstrated that for S >$\text{1}\text{2}$ there is no second-order phase transition, in contrast to the case S = $\text{1}\text{2}$ which was proved to have a tricritical point. This is found to cohere with the previous studies of the dimerized magnetic model chains.