Synthesis of Organosilicon Polymers Based on Carbamide Formaldehyde Resin

The article presents the synthesis of organosilicon compounds based on industrial secondary raw materials of urea-formaldehyde resin and tetraethoxysilane. The structural characteristics of the synthesized hydrophobic polymer have been studied. Compositions of hydrophobic compositions based on synthesized poly (oligomers) have been developed and tested in concrete mixtures.

The Use of Silicones as Extractants of Biologically Active Substances from Vegetable Raw Materials

Based on theoretical studies, the authors of this paper propose the use of cosmetic organosilicon polymers (commonly called silicones) for the extraction of a complex of biologically active substances contained in vegetable raw materials. It is important to note that the biological molecules do not interact with the organosilicones and, therefore, their properties are not altered after the extraction. In this work, we investigate the efficiency of several polyorganosiloxanes as extractants of vegetable raw materials (Calendula Officialis L. and Artemisia Absinthium L.) useful for the preparation of cosmetic emulsions. Specifically, the extraction studies were conducted by using polyorganosiloxanes with a single component (polydimethylsiloxane Silicone Oil 350 cSt, cyclopentasiloxane BRB CM 50, and phenyltrimethicone BRB PTM 20) as well as a mixture (PEG-12 polydimethylsiloxane BRB 526, a solution of dimethiconol in cyclopentasiloxane BRB 1834, and amodimethicone BRB 1288). Compared to water and ethyl alcohol, polyorganosiloxanes are more effective in the extraction of the biologically active substances that are contained in the raw plants. Interestingly, the combination of different polyorganosiloxanes improved the extraction efficiency. The attained knowledge can be helpful in the development of a novel protocol for the formulation of emulsions appealing for cosmetic applications.

CERAMICS BASED ON ORGANOSILICON POLYMERS-PRECURSORS: MICROSTRUCTURE AND PROPERTIES (review). Part 1

The paper considers the process of pyrolysis of polymers-precursors, and also shows the influence of various parameters of technological processes for obtaining ceramics on its composition, structure, and properties. The main types of binary, ternary and multicomponent silicon-based ceramics, methods of its preparation, features of structure and properties are considered, and promising directions of application of ceramics are determined. The possibility of obtaining porous ceramic materials (ceramic foams) with controlled porosity and ceramic composite materials with a given composition is noted.

CERAMICS BASED ON ORGANOSILICON POLYMERS-PRECURSORS: MICROSTRUCTURE AND PROPERTIES (review). Part 2

Shows the scientific approaches of various authors to the study of the microstructure of ceramics, the purpose of which is to elucidate its structural organization at the micro- and nanoscale, as well as the influence of the microstructure on the complex of material properties. Various instrumental methods for studying ceramics (NMR spectroscopy, electron microscopy, х-ray structural analysis, etc.) are considered, the permissible capabilities of research methods and analysis of the results obtained with their correct interpretation are shown. The special role of theoretical modeling in understanding the structure of the considered ceramic materials is noted.

Polyorganosilazanes: production, properties, application

A review is given on the class of organosilicon compounds – polysilazanes. The review includes the history of the discovery of silazanes, the main chemical methods for producing silazanes, the main reactions taking place with the participation of silazanes, and the scope of application of silazanes. The review shows the composition of silazanes. The review consists of 40 literature sources. The synthesis of polyorganosilazanes was first described in 1964 by Kruger and Rohov. In the interaction of ammonia with chlorosilanes (ammonolysis), trimeric or tetrameric cyclosilazanes were formed at the beginning and in the subsequent reaction at high temperatures with a catalyst to obtain polymers with a higher molecular weight. Ammonolysis of chlorosilanes is still the most important synthetic route to polysilazanes. The industrial production of chlorosilanes using the Muller-Roch process, first reported in 1940, served as the cornerstone for the development of silazane chemistry. In the 1960s, the first attempts to turn organosilicon polymers into quasi-ceramic materials were described. At this time, suitable (“pre-ceramic”) polymers are heated to 1000 °C. or higher. It was shown that the elimination of organic groups and hydrogen leads to a rearrangement of the molecular network with the formation of amorphous inorganic materials, which show unique chemical and physical properties. Using polymer-derived ceramics, new applications can be discovered, especially in the field of high-strength materials.

CERAMICS BASED ON ORGANOSILICON POLYMERS-PRECURSORS: METHODS OF PREPARATION AND PROPERTIES (review)

The main types of preceramic organosilicon polymers, general methods of their synthesis and physical, and chemical properties are considered. Methods of shaping, curing and pyrolysis of polymers and the influence of process parameters on the composition, structure and properties of ceramics are described. Separately, the work considers modifying fillers for preceramic polymers, the goals and methods of their introduction into the polymer, the features of processing the compositions and the properties of the products obtained.

Organosilicon polymer-derived ceramics: An overview

Polymer-derived ceramics (PDCs) strategy shows a great deal of advantages for the fabrication of advanced ceramics. Organosilicon polymers facilitate the shaping process and different silicon-based ceramics with controllable components can be fabricated by modifying organosilicon polymers or adding fillers. It is worth noting that silicate ceramics can also be fabricated from organosilicon polymers by the introduction of active fillers, which could react with the produced silica during pyrolysis. The organosilicon polymer-derived ceramics show many unique properties, which have attracted many attentions in various fields. This review summarizes the typical organosilicon polymers and the processing of organosilicon polymers to fabricate silicon-based ceramics, especially highlights the three-dimensional (3D) printing technique for shaping the organosilicon polymer- derived ceramics, which makes the possibility to fabricate silicon-based ceramics with complex structure. More importantly, the recent studies on fabricating typical non-oxide and silicate ceramics derived from organosilicon polymers and their biomedical applications are highlighted.

A Foreword from the Editor-in-Chief

Accompanying the development of petrochemical industry, great progress has been achieved in the organic polymer materials. It is well known that the conventional polymer materials usually consist of organosilicon polymers, polycarbonates, polyethylene, polyamide, polyurethane, polysulfone, phenolic resin and so on. Although their synthesis and applications have been well developed, the further research on them still has great significance. Moreover, natural polymers such as polysaccharides, tannins, cellulose also occupy an important position in the family of the organic polymer materials.