Polymer Science, Series C最新文献

The luminescent properties of an organic dyad that combines two different luminophores, hydroxy-substituted 2,4,5-triarylimidazole and 8-azomethine-7-hydroxycoumarin, in its molecule have been studied in seventeen polymer matrices obtained by photocuring, which are represented by linear poly(meth)acrylates differing in the amount of hydroxyl groups and acrylic network polymers differing in the nature of crosslinking oligomeric blocks. The dependence of the luminescent properties of materials on the wavelength of excitation light, as well as on the presence and amount of hydroxyl groups in polymers; the presence of urethane groups, ether bonds, and aromatic moieties (individually or in combination); and flexibility and conditional polarity of the matrix, has been established.

The current state of research on composites containing graphene derivatives as nanofillers is considered. The results of works carried out at the Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences on the synthesis of filled composites based on polylactide and carbon nanofillers, reduced graphene oxide and graphite nanoplates, by two independent methods, ecofriendly solid-phase mixing of components under shear deformations and liquid-phase synthesis, are summarized. A comparative study of the mechanical, thermal, and electrical properties of the composites is performed depending on the production method and the nature of the used nanofillers, and their influence on the structure and complex of properties of the resulting composite materials is established.

Solid dispersions based on acyclovir and polysaccharides (starch and sodium carboxymethylcellulose) have been prepared by means of mechanochemistry. Mechanical co-processing of the drug and the polymers in a ball mill, an extruder, and a pulse mechanical action cell has led to amorphization of acyclovir, followed by its uniform distribution in the polymer matrix. A set of the IR and UV spectroscopy, DSC, and X-ray diffraction analysis data has revealed the presence of intermolecular interactions between the polysaccharide matrix and the drug. The obtained materials can be considered as potential system for further investigation as solid formulations of acyclovir with improved bioavailability.

Nanofibers based on polyacrylonitrile with graphite have been obtained using the electrospinning technique. The structure, as well as thermal and electrical properties, of nanofibers has been studied. The influence of the rheological characteristics of solutions and the conditions of the electrospinning process on the structure of nanofibers is shown. Changes in the supramolecular structure characteristics of nanofibers during electrospinning have been revealed.

Silicone resins, which exhibits excellent heat-resistance, chemical stability and adhesion, are indispensable components in high temperature resistance coatings. Herein, we summarize a comprehensive survey of developments on heat-resistant silicone-based coatings. The influence of heat-resistant of modifying silicone resin chain segment, such as main chain modification and side main modification are discussed. Then, the physical and chemical properties of inorganic fillers combined with silicone resins are summarized for the aim of ceramization and further improving the degree of heat-resistant. Finally, the challenges and future opportunities of heat resistance coatings based on silicone resins are considered.

The development of organometallasiloxane chemistry from first polymeric systems to individual organometallasiloxanes and functional oligomeric compounds is considered. The structural diversity of organosilicon precursors and the variability of metal-containing components are presented. Synthetic approaches are considered in detail, including those that allow targeted production of organometallasiloxanes of a certain structure. Using the example of organometallasiloxanes synthesized from trifunctional organoalkoxysilanes, methods for the synthesis of unique stereoregular functional cyclosiloxanes and their derivatives are highlighted. Considerable attention is given to the applied aspects of various structure organometallasiloxanes and their derivatives. The state of the art of the chemistry of organometallasiloxanes and their further evolution are evaluated critically.

Modern research in the field of synthesis of organofunctional oligosilsesquioxanes is considered. Relationships between the composition and structure of oligomeric organosilsesquioxanes and the conditions for their formation during the hydrolytic and acidohydrolytic polycondensation of organotrialkoxysilanes containing various functionalities, such as methacrylic, aminopropyl, carboxyl, and cyclotriphosphazene groups, in organic radicals bonded to silicon atoms are shown. A comparative analysis of approaches to the synthesis of organofunctional incompletely condensed oligosilsesquioxanes has been carried out.

The available information concerning the preparation and properties of modifying siloxane coatings on the surface of fibrous materials, as well as a number of other functional silicone polymers for hydrophobization of fibers, textiles, leather, building materials, creation of adhesive compositions, and other practically valuable silicone products has been generalized.

Environmentally friendly method for the synthesis of crosslinked poly(siloxane-urethanes) avoiding the use of toxic isocyanates has been presented. The synthesis has been performed in two stages: at the first stage, non-isocyanate poly(siloxane-urethanes) have been synthesized via aminolysis of cyclocarbonates (differing in the structure and functionality) with oligomer dimethylsiloxanes bearing aminopropyl and ethoxy substituents, and crosslinked non-isocyanate poly(siloxane-urethanes) have been obtained via hydrolysis of the ethoxy groups with air moisture. According to the TGA data, processes of thermooxidative decomposition of the non-isocyanate poly(siloxane-urethanes) begin at 240‒260°C, depending on the structure of the organic block. Structural organization of the films has been investigated and glass transition temperature of two blocks (flexible siloxane and rigid urethane ones) has been determined by means of DSC and TMA. Surface of the film samples of non-isocyanate poly(siloxane-urethanes) has been assessed by means of scanning electron microscopy.