Interaction between sulfur dioxide and a co-reduced alumino-ferrous catalyst

From gamma-resonance spectroscopy investigations it was shown that as a result of absorption of SO₂ from moist air by a CO-reduced alumino-ferrous catalyst SO₂ is irreversibly bound to form hydrated iron sulfate at 393–523 K, and that CO molecules are in part reversibly substituted by SO₂ molecules in the Fe²⁺ coordination sphere at 573–723 K.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 3, pp. 220–225, May-June, 1992.     

Viscosity of Polymer–Bitumen Binders

Polymer–bitumen binders for the highway engineering were obtained by the addition of a ternary ethylene–propylene rubber to a bitumen. The addition of a vulcanizing agent to a polymer–bitumen composition caused the structuring of the system through cross-linking of rubber molecules in the bitumen matrix that was confirmed by the study of structural viscosity of the polymer–bitumen compositions, as well as molecular mobility by the methods of NMR-relaxation and pulsed field gradient NMR-relaxation (self-diffusion).     

Properties of Bitumens Modified by Thermoplastic Elastomers

The possibilities of modification of bitumens by blend thermoplastic elastomers (TPEs) with predominantly maximum long main chains are studied. The evaluation of their properties shows that the blend TPEs display a stronger effect in low-viscosity bitumens, which is associated with improved compatibility of TPEs in bitumens, as evidenced by convergence of the solubility parameters of TPEs and of the aliphatic part of the malthene fraction of bitumens. The relaxation properties of the modified bitumens allow us to judge their stability under operating conditions, to evaluate this effect quantitatively, and to determine the activation energy of the relaxation process.