Effect of Different Synthetic Resins on Soil Nano- and Microstructure

Abstract—

The use of synthetic and natural resins in the fixation of organomineral matter for further studies is common, e.g. in the micromorphological study of soils, since the procedure of making thin sections includes the impregnation of the sample with the filling materials (resins). At the same time, their effect on the soil structure remains poorly known. In this article, an experiment to study the impact of synthetic and natural resins on the nano- and microstructure of soil during impregnation is considered. First data on the characteristics of resins frequently used in laboratories, as well as on their effects on the structure of soil samples have been obtained with small-angle X-ray scattering and computed tomography techniques. The X-ray transparency of fixing materials was detected. Subsequent impregnation of the AU horizon fraction from Haplic Chernozems of Kursk oblast by fixing materials allowed establishing their influence on the change in size of soil nanostructural heterogeneities. The experiment with different horizons of Protosalic Solonetz attests to a decrease in the size of nanoheterogeneities with depth in the impregnated soil as compared with that in the native soil. At the microlevel, a decrease in microporosity within the first percent after polymerization of the fixing material has been proved. As a result of studies of nanoheterogeneities in the soil, scanning parameters have been experimentally selected at the BioSAS station of the Kurchatov`s synchrotron radiation source. The nanostructure of soil core samples and separate fractions has been studied for the first time at this station. The above results can be used in sample preparation and further analysis of organomineral objects (soils, rocks) for a number of studies that require fixation of the substance structure at different dimensional levels.