Hydrolytic degradation and thermal stability of poly(naphthylimides) based on naphthalene-1,4,5,8-tetracarboxylic dianhydride and bis(naphthalic anhydrides)

The molecular properties of a number of new poly(naphthylimides) derived from naphthalene-1,4,5,8-tetracarboxylic dianhydride and bis(naphthalic anhydrides) have been studied. On the basis of hydrodynamic studies of the polymers at various stages of their thermal degradation in 96% H₂SO₄ and thermogravimetric measurements, the hydrolytic stability and thermooxidative resistance of the polymers have been compared. A correlation between the experimental data and the chemical structure of molecular chains has been established.     

Effect of conformational rigidity on the glass transition and initial decomposition temperatures of polyimides

The dependence of the glass transition and initial decomposition temperatures of polyperyleneimide and polynaphthylimide on the conformational rigidity was studied by the Monte Carlo, Kuhn segment, and quantum chemical AM1 methods. The corresponding linear plots can be used for estimation of the glass transition and initial decomposition temperatures when experimental determination is difficult.     

Polycondensation in supercritical carbon dioxide: a contribution from the A. N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences

Russian Chemical Bulletin - The achievements of polycondensation in supercritical carbon dioxide over the past 20 years are considered. The contribution of the A. N. Nesmeyanov Institute of...     

A new method for the synthesis of sulfonated polynaphthylimides

A new method for the synthesis of sulfonated polynaphthylimides has been developed on the basis of the postsulfonation of high-molecular-mass polynaphthylimides with a sulfuric acid-oleum mixture. Sulfonated polymers of this type have been obtained from the polycondensation products of 5-phenylthiophenylene-1,3-diamine with dianhydrides of 1,4,5,8-naphthalenetetracarboxylic acid and 4,4′-(1,4-phenylenedicarbonyl)-bis-naphthalene-1,8-dicarboxylic acid. It has been shown that hydrogen peroxide oxidation of sulfide bridge groups of these polymers in an acidic medium yields high-molecular-mass compounds that contain sulfonic bridge fragments and, therefore, have increased thermal stabilities and enhanced proton conductivities.     

Monopole solutions as three-dimensional generalizations of Kronecker series

We investigate the Dirac monopole on a three-dimensional torus as a solution of the Bogomolny equations with nontrivial boundary conditions. We show that a suitable analytic continuation of the obtained solution is a three-dimensional generalization of the Kronecker series, satisfies the corresponding functional equation, and is invariant under modular transformations.     

Averaging initial data in applied problems

A method for averaging experimental data is proposed and formulas for averaged values of these data are given. A two-sided estimate accurate to the order of approximation of the averaged data is obtained.