Key Engineering Materials Vol. 899

Abstract: pH-switchable chain transfer agent 1-cyano-1-methylethyl (phenyl)(pyridin-4-yl)-carbamodithioate (CMPC) was synthesized and reversible addition-fragmentation chain-transfer (RAFT) polymerization of styrene in presence of CMPC was studied. It was shown that presence of CMPC affects molar mass distribution and kinetic features and realizes supposed mechanism of RAFT polymerization. Different effect of CMPC on polymerization of styrene in presence of protic acids was studied.

Abstract: Foaming of the biodegradable polymer composites and melting of the gas-filled materials were studied using thermal microscopy. Composite materials under investigation were based on the low density polyethylene and natural products used as the polymer composite fillers: wood flour and corn starch. Porous structure of the composite material was obtained using a chemical porogen “Hydrocerol BIF”. It has been shown that the foaming and melting processes occur differently in the polymer composite samples containing either different amount of the fillers or the same content of the filler with different particle size fractions. Thermal behavior of the composite samples was shown to be different from the behavior of pure polyethylene, which indicates non-additivity (superadditivity) of the contribution of the above components to the thermal behavior of the final composite material. All the results obtained using heating stage (hot stage) microscopy were in good agreement with the SEM and DSC data.

Abstract: One of the most important applications of polymeric porous nanomaterials is the design of nanoporous structures for operation in patch-clamp systems allowing to establish a gigaohm contact, as well as for the measurements of biomolecules, informational macromolecules, including DNA, translocating through the nanopore arrays. Development of nanopore sequencing techniques leads to fundamentally new big data arrays, but their representativeness and validity, as well as the validity of counting of biomacromolecular particles based on ultramicropore arrays, strongly depends both on the pore size (in engineering lithography unimodal pore size distribution is optimal) and the accuracy of the size distribution measurements using instrumental methods. However, the former is unattainable when using soft matter or stretchable, plastic and elastic polymer materials and films, while the latter depends on the metrological parameters of the instrumental and algorithmic porosimetry techniques. Therefore in this paper the question about the applicability of polymer materials with pore arrays for the studies of biomacromolecules and bionanostructures is proposed to be answered using a comparative analysis of two different porosimetry approaches with the resolution not lower than electron microscopic one.

Abstract: Additives were selected and a method for modifying the structure of gypsum-containing materials for construction purposes and a method for their dispersion were developed. Based on the selected modifiers, effective compositions of composite gypsum-containing materials based on local and secondary raw materials were developed, and an increase in their strength and resistance to water was established.

Abstract: Rosin, or colophony, and composite materials, which consist of components based on rosin and rosin products, are extensively used in various industries, in particular, as one of the main components of the composite materials for road marking. At the same time, little research has been done to study of the physicomechanical and associated physicochemical characteristics of these materials, the influence on these characteristics of the internal bounding surface of the components in wide temperature ranges and in the dynamic mode of external deforming effects.

Abstract: It is known that epoxy resins (ES) and materials based on them are widely used in various areas of natural economy due to their valuable properties: low shrinkage during curing, high adhesion to various materials, chemical resistance, good physical and mechanical properties, and excellent dielectric properties [1].

Abstract: Questions of the construction of dispersed structures of polymer composite materials using a generalized model of dispersed filled polymer composite materials (DFPCM) are studied. Using the parameter of maximum proportion of filler (φ_m) allows you to take into account the size, shape, and distribution of part of the dispersed filler at the same time. The transition to generalized and specified parameters when describing the structure of the DFPCM leads to the possibility of highlighting the optimal criteria for obtaining systems with the highest strength characteristics. The transition to generalized and reduced parameters when describing the structure of DFPCM leads to the possibility of selecting optimal criteria that ensure obtaining systems with the necessary level of rheological, electrochemical, physico-mechanical and other characteristics.

Abstract: Microencapsulation of drugs is used for a long time to improve their properties. It was carried out a comparative assessment of the physical and physicochemical methods of microencapsulation on the example of some drugs. The spray drying method was selected from the physical methods. Physicochemical method based on simple coacervation was implemented by changing the solvent. A study and comparison of the properties of the products were obtained by UV and IR spectroscopy, liquid chromatography, electron microscopy. It was carried out a comparative assessment of the release profile of the active substance from microcapsules obtained by various methods. Using the example of furacilin microcapsules has been shown an increase in the biological activity of substances encapsulated in water-soluble polymers. The particle size distribution was determined by analyzing their trajectories. The main advantages and disadvantages of the two investigated encapsulation methods are outlined.

Abstract: The article presents a scientific review of the literature on the known methods of producing polyetheretherketane and composites based on it used in the medical manufacture practice of implants. The main substances used in the synthesis of PEEK, as well as modifiers included in the PEEK-based composite material, are generalized.

Abstract: This article presents a scientific review of the literature on biodegradable polymer composite materials based on polyvinyl chloride. We summarized data on the effect of modifiers of natural and synthetic origin on the biodegradability of polyvinyl chloride material. The main methods for studying the biodegradability of polymeric materials are considered.