Soviet Scien Rev Series Sec B

Part one of this review volume describes experimental investigations of mechanically-produced physical and chemical changes in coal. The author discusses the basic laws underlying the changes detected in composition, structure and reactivity and show the environmental influence on the direction taken by the mechanochemical changes. Part two gives a systematic overview of experimental data on the properties of the free radicals that arise when organic systems are subjected to mechanical forces (principally comminution). The structure of polymeric radicals and their reactivity in decomposition, addition and substitution reactions over the temperature range 77-295 K are reviewed with special attention to kinetic data, obtained under non-diffusion conditions, characterizing the elementary stages. And part three reports on concepts developed in the field of mechanochemistry and the mechanical activation of inorganic solids. By showing the organic link between the changes in the reactivity of solids the nature of the structural disordering of the activated substances and the kinetics of the relaxation of such disordering, the authors reveal the dynamic character of mechanical activation as a process determining the state of the reagent at different moments during a reaction.

Table of Contents:
Part 1 Mechanico-chemical transformations of the organic compounds in coal: the change in the supermolecular structure of coals and the short range order in the arrangement of the carbon atoms; the emission of high energy electrons; the change in the molecular weight distribution; the yield of soluble fractions and the change in their composition and structure, volatile products; the rupture of the chemical bonds of the organic compounds in coal and the change in their structure; energy yield from the mechanical degradation of the organic compounds in coal; the reactivity of mechanically treated coals. Part 2 Free radical reactions in the mechano-chemistry of solid organic polymers: the structure of macro-radicals and the mechanism of their formation in polymers exposed to mechanical action; the course and kinetics of radical reactions initiated by mechanical forces; the effect of mechano-chemical radical reactions on the properties of solid organic systems. Part 3 Achievements and prospects in mechano-chemistry: introductory remarks; the physical foundations of mechano-chemistry; the chemical consequences of mechano-activation; the kinetics of mechano-chemical processes; potential technological uses of mechano-chemistry and mechanical activation.