M. V. Mokeev

Hydration of Portland cement in the presence of high activity aluminum hydroxides

The effect of highly dispersed amorphous aluminum hydroxides on the hydration of Portland cement was studied by the solid-state 27Al and 29Si NMR spectroscopy. It was established that in the presence of aluminum hydroxides the decrease in the setting time of a cement paste is due to rapid formation of ettringite phase, with contribution of admixture material the main and contribution of aluminum-containing phases at this stage insignificant.

Influence of ultradispersed silicas on Portland cement hydration

Solid-state 29Si NMR spectroscopy was applied to examine Portland cement hydration and cement stone composition as influenced by the nature of commercial ultradispersed silicas (microsilica, precipitated silica, and colloidal silica).

Structure of products of aldoses condensation with thioglycolic acid hydrazide

Condensation products of thioglycolic acid hydrazide with aldoses (L-arabinose, D-xylose, L-rhamnose, D-galactose, D-glucose, D-mannose) exist in the D2O solution as a tautomeric mixture of α,β-pyranose form and six-membered 1,3,4-thiadiazine form present as two diastereomers.

Role of Structural Characteristics of Aromatic Polyimides in Carbonization

The influence of the structural characteristics of polyimides belonging to four standard classification groups was analyzed. The main factors responsible for formation of ordered and/or turbostratic carbon structures in the course of carbonization were studied for the example of film and fibrous materials.

Hydration of portland cement in the presence of aluminum-containing setting accelerators

Portland cement hydration in the presence of two different aluminum-containing compounds, highly dispersed amorphous Al(OH)3 and aqueous solution of aluminum hydroxosulfate Al(OH)1.78(SO4)0.61, was studied by solid-state 27Al and 29Si NMR spectroscopy.

Thermochemical Transformations of Hydrolysis Lignin

Conclusions on the reactivity of lignin in thermal processes are made on the basis of published data and results of thermal analysis of lignin samples from certain hydrolysis enterprises.

Surface modification of detonation nanodiamonds by the perfluorobutyl radical

The method was developed for surface defunctionalization of detonation nanodiamonds by substitution of a perfluorinated organic radical for hydroxyl and carboxyl groups. Size-mass distributions of modified particles of detonation nanodiamonds in water and toluene were studied

Potential activity of hydrolytic lignin in copolymerization reactions

Structural-molecular characteristics of hydrolytic lignin samples from various factories were studied and their potential activity in copolymerization with polyacrylonitrile was determined.

Structural features of carbon products: an NMR study

Structural characteristics of a series of carbon products and intermediates of carbonization of some polymers were studied by high-resolution solid-state 13C NMR spectroscopy, with comparison of the experimental and calculated spectroscopic data.

Thermochemical reactions of polyacrylonitrile with fullerene C60

Reactions occuring in mixtures of polyacrylonitrile with fullerene C60 at 20-1000°C were studied by thermal analysis. The greatest thermal effects were observed in diffusion-controlled reactions of anionic polyacrylonitrile with fullerene. Carbonizate is formed with the yield of about 60%, which is of practical interest.