Nanocomplexes of Magnesium Phenylsiloxanes - Moleculer Structere and Properties

Abstract

Polyphenylsiloxanes containing magnesium (polymagnesiumphenyl siloxanes) with Si:Mg ratios of 1:1.5 and 1:2 have been synthesized by the exchange reaction in a mixture of benzene (toluene)–dimethyl sulfoxide with yields of 58 and 72%, respectively. The composition and structure of the synthesized polymers have been studied by the methods of positron annihilation spectroscopy (PAS), X-ray diffraction analysis (XRD), 29Si nuclear magnetic resonance (NMR), and infrared spectroscopy (IR). The cross-section surface area (S) (by the Miller–Boyer method) and coherent scattering regions (CSR) volumes have been calculated based on the XRD data. The PAS data allowed calculating the specific volumes of Ps and e+ “traps”. The T3 and T2 signal areas in 29Si NMR spectra enabled us to determine the structure of the unit cell of polymagnesiumphenyl siloxanes (PMgPS). As was demonstrated by the electron microscopy, PMgPSs were in the form of spherical particles of a radius of 50–120 nm. The polymers physical–chemical characteristics were determined from nitrogen adsorption. Based on the specific adsorption area, the radii of spherical particles in a densely packed layer, whose size depends proportionally on the specific polarization potential and the specific area, have been calculated. The calculated size values for spherical particles are similar to those found by the method of electron microscopy. An assumption on a fractal structure of spherical particles has been made on the basis of the calculated data, and data of scanning electron microscopy.