Polymer Science, Series C最新文献

The review summarizes the data on the synthesis, physicochemical properties, and biological activity of poly(1-vinyl-1,2,4-triazole) and its nanocomposites with silver nanoparticles. The results of studying the antibacterial and antitumor activity of the polymers and nanocomposites and their immunomodulatory ability, toxicity, and interaction with body cells, as well as the prospects for their use in the development of medical materials, are presented.

This review is the first attempt to consider application of some principles of green chemistry to reversible-deactivation radical polymerization mediated by nitroxides. The results of controlled synthesis of easily degradable polymers and polymers synthesized under conditions of green chemistry by photopolymerization, polymerization in supercritical carbon dioxide, and polymerization of monomers from renewable raw materials are discussed.

A brief overview of works in the field of mechanisms of reactions underlying the green chemistry of polyurethanes is presented. The main attention is paid to the processes of the formation of nonisocyanate urethanes from cyclocarbonates and amines and the thermal decomposition of acyl azides as a phosgene-free method for the preparation of isocyanates in statu nascendi. The results of the study of the functional composition of cyclocarbonate-containing triglycerides the derivatives of soybean and sunflower oils, and the prospects for using renewable plant raw materials for the synthesis of new urethanes are also discussed.

In recent decades, the need to capture carbon dioxide from industrial gas streams, its storage, and utilization has been justified as a rule by environmental problems. However, the capture of CO₂ from industrial gas mixtures is an independent important issue of chemical technology. The review addresses consideration and analysis of polymer materials for the membrane separation of CO₂-containing mixtures which are of interest for purification of natural gas, biogas, and flue gases and separation of hydrogen from methane and water gas conversion products. Therefore, gas pairs CO₂/CH₄, CO₂/N₂, and CO₂/H₂ are relevant for membrane separation. Promising polymer materials should possess the beneficial combination of CO₂ permeability and selectivity for the gas pair of interest, that is, should be located near the upper bound of the Robeson diagram or be above it. For separation of the first two gas pairs good gas-separation parameters are exhibited by rigid-chain highly permeable glassy polymers of various classes (polymers of intrinsic microporosity, polyimides, polynorbornenes, polybenzoxazoles). For separation of the gas pair CO₂/N₂ the most advantageous properties are shown by polymers bearing functional groups capable of specific interactions with carbon dioxide (aliphatic polyethers and polyimides with their oligomer moieties, polynorbornenes carrying Si‒O–C and Si–O–Si groups, polymers with ionogenic groups). Thermally stable barrier polymers based on polybenzoxazoles show promise for purification of hydrogen from carbon dioxide at high temperatures.

Publications showing the prospects of combining computer simulation with atomic force microscopy in the study of polymer biological objects and materials for various purposes are analyzed. The problems that arise when these methods are used together are described. Three main directions are presented in which atomic force microscopy is used in conjunction with computer simulation: study of the surface topography of polymer materials; measurement of the force curve of the interaction of the atomic force probe with polymer structures; and determination of the energy of intermolecular interactions.

Nanocomposite networks of surfactant micellar chains and natural bentonite clay nanoplates are studied by rheometry, small-angle neutron scattering, and cryogenic transmission electron microscopy. It is shown that, in an aqueous medium in the presence of a small part of an anionic surfactant, sodium dodecyl sulfate, the molecules of a biodegradable zwitterionic surfactant, oleyl amidopropyl dimethyl carboxybetaine, form micron-length living micellar chains which entangle and form a network possessing well-defined viscoelastic properties. It is found that addition of negatively charged clay nanoplates leads to an increase in viscosity and relaxation time by an order of magnitude. This is explained by the incorporation of the nanoplates into the network as physical multifunctional crosslinks. The incorporation occurs via the attachment of semispherical end-caps of the micelles to the surface of the particles covered with a surfactant layer, as visualized by cryogenic transmission electron microscopy. As the amount of nanoplates is increased, the rheological properties reach plateau; this is associated with the attachment of all end parts of micelles to nanoplates. The developed nanocomposite soft networks based on safe and eco-friendly components are promising for various practical applications.

Polylactide-based materials are often considered an alternative to materials produced from traditionally hardly degradable polymers. Porous polylactide membranes, matrices, and scaffolds are especially attractive for use in biomedicine. The review concerns the physicochemical basis and structural and morphological opportunities of various methods for the manufacture of porous polylactide, such as sintering, 3D printing, electrospinning, foaming, etching, and the processes of phase separation and orientational drawing. Special attention is focused on the effect of porous structure parameters on the rate of hydrolytic degradation of the polymer and the prospects for the development of application areas of similar porous materials.

In recent years, the problem of polymer processing has become quite urgent owing to the accumulation of huge amounts of unprocessed polymer municipal solid waste in the environment. The authors discuss the main environmental problems associated with environmental pollution with polymer waste, as well as modern methods of separation, processing (including processing into secondary material resources and thermal processing into thermal and electrical energy) and assessment of the life cycles of polymer municipal solid waste.

The effect of cationic polyelectrolyte poly(diallyldimethylammonium chloride), anionic polyelectrolyte potassium lignohumate, and their interpolyelectrolyte complex on the aggregate composition and phytotoxicity of constructozem, an artificially constructed soil, is investigated. The original constructozem is characterized by a wide range of structural aggregates with a high proportion of large particles. Addition of the polycation to the constructozem completely destroys large aggregates, while addition of the polyanion has almost no effect on particle size distribution. The polycomplex sharply reduces the proportion of large particles and blocks the appearance of small particles, thereby significantly increasing the content of agronomically valuable aggregates in the constructozem and, at the same time, stimulating the growth and development of plants.