Теплопроводность композита на основе н-алкана и наноразмерных добавок

A K Borisov, V M Egorov, V A Marikhin Composites based on n-alkane and nanoscale additives were investigated to determine the efficiency of heat transfer during phase transitions in phase change materials. It was found that the thermal conductivity of composite materials is several times higher than the thermal conductivity of the initial n-alkane. The observed effect is due to the specificity of the supramolecular nanostructure of the composite, which differs from the supramolecular structure of the nonadecane.

Polyhalogenated aminobenzonitriles vs their co-crystals with 18-crown-6: amino group position as a tool to control crystal packing and solid-state fluorescence

A series of para- and ortho-aminobenzonitriles differing in the nature and number of halogen substituents was used to synthesize 2:1 co-crystals with 18-crown-6 ether. Supramolecular structure of the obtained co-crystals...

Effect of Borpolymer on Mechanical and Structural Parameters of Ultra-High Molecular Weight Polyethylene

The paper presents the results of studying the effect of borpolymer (BP) on the mechanical properties, structure, and thermodynamic parameters of ultra-high molecular weight polyethylene (UHMWPE). Changes in the mechanical characteristics of polymer composites material (PCM) are confirmed and complemented by structural studies. X-ray crystallography (XRC), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and infrared spectroscopy (IR) were used to study the melting point, morphology and composition of the filler, which corresponds to the composition and data of the certificate of the synthesized BP. Tensile and compressive mechanical tests were carried out in accordance with generally accepted standards (ASTM). It is shown that BP is an effective modifier for UHMWPE, contributing to a significant increase in the deformation and strength characteristics of the composite: tensile strength of PCM by 56%, elongation at break by 28% and compressive strength at 10% strain by 65% compared to the initial UHMWPE, due to intensive changes in the supramolecular structure of the matrix. Structural studies revealed that BP does not chemically interact with UHMWPE, but due to its high adhesion to the polymer, it acts as a reinforcing filler. SEM was used to establish the formation of a spherulite supramolecular structure of polymer composites.

Effect of the Hemin Molecular Complexes on the Structure and Properties of the Composite Electrospun Materials Based on Poly(3-Hydroxybutyrate)

The creation of innovative fibrous materials based on biodegradable semicrystalline polymers and modifying additives is an urgent scientific problem. In particular, the development of biomedical materials based on molecular complexes and biopolymers with controlled properties is of great interest. The paper suggests an approach to modifying the structure and properties of the composite materials based on poly(3-hydroxybutyrate) (PHB) obtained by the electrospinning method using molecular complexes of hemin. The introduction of 1–5 wt. % of hemin has a significant effect on the supramolecular structure, morphology and properties of PHB-based fibers. Changes in the supramolecular structure intensified with the increasing hemin concentration. On the one hand, a decrease in the fraction of the crystalline phase by 8–10% was observed. At the same time, there is a decrease in the density of the amorphous phase by 15–70%. Moreover, the addition of hemin leads to an improvement in the strength characteristics of the material: the elongation at break increased by 1.5 times, and in the tensile strength, it increased by 3 times. The antimicrobial activity of the hemin-containing composite materials against Escherichia coli and Staphylococcus aureus was confirmed. The obtained materials are proposed to be used in the creation of composite systems for regenerative medicine.

Thermal conductivity of PCM materials based on a composite consisting of n-alkane and nanoscale additives

Composites based on n-alkane and nanoscale additives were investigated to determine the efficiency of heat transfer during phase transitions in phase change materials. It was found that the thermal conductivity of composite materials is several times higher than the thermal conductivity of the initial n-alkane. The observed effect is due to the specificity of the supramolecular nanostructure of the composite, which differs from the supramolecular structure of the nonadecane.

Binding of Gold(III) from Solutions by the [Ag6{S2CN(CH2)6}6] Cluster: Synthesis, Thermal Behavior, and Self-Organization of the Supramolecular Structure of the Double Complex [Au{S2CN(CH2)6}2]2[AgCl2]Cl·2CHCl3 (Role of Secondary Au⋅⋅⋅Cl, Ag⋅⋅⋅S, and Cl⋅⋅⋅Cl Interactions)

The capability of silver(I) cyclo-hexamethylenedithiocarbamate to concentrate gold(III) from solutions characterized by a high level of salinity (5.15 M NaCl) into the solid phase has been established. The double chloroform-solvated Au(III)–Ag(I) complex [Au{S2CN(CH2)6}2]2[AgCl2]Cl·2CHCl3 (I) was preparatively isolated as an individual form of binding of [AuCl4]– anions. The composition of the ionic structural units of compound I indicates that gold(III) binding from a solution to the solid phase is accompanied by the complete redistribution of the HmDtc ligands between the coordination spheres of Ag(I) and Au(III). Complex I characterized by IR spectroscopy, simultaneous thermal analysis, and X-ray structure analysis (CIF file CCDC no. 2051654) exhibits the supramolecular structure containing two oppositely charged pseudo-polymeric subsystems. Complex cations [Au{S2CN(CH2)6}2]+ and anions [AgCl2]– (in a ratio of 2 : 1) form a complicatedly organized cation-anionic pseudo-polymeric ribbon ({[Au(HmDtc)2]⋅⋅⋅[AgCl2]⋅⋅⋅[Au(HmDtc)2]}+)n due to secondary interactions Ag⋅⋅⋅S (3.2613 Å) and Au⋅⋅⋅Cl (3.2765 Å). The pseudo-polymeric ribbon consists of two rows of cations and a row of anions. The outer-sphere chloride ions combine the solvate chloroform molecules by two equivalent hydrogen bonds Cl⋅⋅⋅H–C yielding anion-molecular triads [Cl3CH⋅⋅⋅Cl⋅⋅⋅HCCl3]–, which are involved in the formation of the supramolecular ribbon due to the secondary Cl⋅⋅⋅Cl interactions (3.4058 Å) between the nonequivalent chlorine atoms of the nearest solvate molecules. The study of the thermal behavior of complex I makes it possible to determine the character of thermolysis and conditions for the quantitative regeneration of bound gold.