The Effect of Reactive Electric Field-Assisted Sintering of MoS2/Bi2Te3 Heterostructure on the Phase Integrity of Bi2Te3 Matrix and the Thermoelectric Properties

In this work, a series of Bi2Te3/X mol% MoS2 (X = 0, 25, 50, 75) bulk nanocomposites were prepared by hydrothermal reaction followed by reactive spark plasma sintering (SPS). X-ray diffraction analysis (XRD) indicates that the native nanopowders, comprising of Bi2Te3/MoS2 heterostructure, are highly reactive during the electric field-assisted sintering by SPS. The nano-sized MoS2 particles react with the Bi2Te3 plates matrix forming a mixed-anion compound, Bi2Te2S, at the interface between the nanoplates. The transport properties characterizations revealed a significant influence of the nanocomposite structure formation on the native electrical conductivity, Seebeck coefficient, and thermal conductivity of the initial Bi2Te3 matrix. As a result, enhanced ZT values have been obtained in Bi2Te3/25 mol% MoS2 over the temperature range of 300–475 K induced mainly by a significant increase in the electrical conductivity.

Fabrication of Hierarchical Nanocomposites through a Nature-Mimic Method: Depositing MoS2 Nanoparticles on Carbon Nitride Nanotubes by Polydopamine Coating

The combination of 1D nanotubes with 0D nanoparticles to integrate a nanocomposite structure has attracted increasing research interest, while the interfacial interaction plays an important role in such composites. This paper presents a facile and universal approach for the fabrication of hierarchical NP-NT nanocomposites with improved photocatalytic performances by mussel chemistry. Polydopamine (PDA) serves as the biomimetic adhesive layer and then connects MoS2 nanoparticles with g-C3N4 nanotubes (CNNTs). The obtained nanocomposites were characterized by FT-IR spectra, XRD, SEM, TEM, XPS, UV-vis DRS, and PL. Compared with unmodified CNNTs, the as-prepared MoS2-PDA-CNNT composites exhibited an enhanced photocatalytic properties for the degradation of methylene blue (MB) under visible light irradiation. This research would provide a green and versatile method to construct hierarchical structured nanocomposites with high catalytic activity.

Structure and mechanical properties of composite amorphous-crystalline Al-based materials synthesized by high pressure torsion.

The results of the structural studies and hardness measurements of bi-and three-layer samples obtained by high pressure torsion of melt-spun ribbons of Al-based alloys with amorphous and crystalline structures have been presented. It has been established that straining of amorphous ribbons results in formation of nanocomposite structure while that refinement of crystalline structure and increase of microstrains takes place in crystalline ribbon. It has been found that the hardness of the consolidated samples increases with the increase of the deformation level up to 4,7 GPa.

In Situ Ultraviolet Polymerization Using Upconversion Nanoparticles: Nanocomposite Structures Patterned by Near Infrared Light

In this paper, we report an approach to polymerization of a nanocomposite containing UV-polymerizable organic material and inorganic, NaYbF4:Tm3+ core-based nanoparticles (NPs), which are optimized for upconversion of near infrared (NIR) to ultraviolet (UV) and blue light. Our approach is compatible with numerous existing UV-polymerizable compositions and the NaYF4: Yb, Tm3+ core-based NPs are much more stable against harsh conditions than NIR organic photo-initiators proposed earlier. The use of a core-shell design for the NPs can provide a suitable method for binding with organic constituents of the nanocomposite, while maintaining efficient NIR-to-UV/blue conversion in the NaYbF4 core. The prepared photopolymerized transparent polymer nanocomposites display upconversion photoluminescence in UV, visible and NIR ranges. We also demonstrate a successful fabrication of polymerized nanocomposite structure with millimeter/submillimeter size uniformly patterned by 980 nm irradiation of inexpensive laser diode through a photomask.

Study of the Effect of Organoclay on the Structure of Cable PVC Compound

The effect of the organoclay content in polyvinyl chloride plasticate on the features of the supramolecular structure and properties of the layered silicate nanocomposite was studied. X-ray diffraction studies showed that with an increase in the number of layered silicate nanofiller, the nanocomposite structure goes from intercalated to exfoliate. Using a combination of scanning and atomic force electron microscopy methods, it has been shown that when organomodified montmorillonite is introduced into polyvinyl chloride plastic compound, montmorillonite nanoparticles act as crystallization nuclei and along with the preservation of “old” supramolecular structures in the melt, “new” supramolecular formations appear. When studying the dependence of tensile strength of nanocomposite polyvinyl chloride on the content of nanofiller, it was found that the maximum strength of the nanocomposite is achieved at a 5-7 % organoclay concentration.

THE MECHANISMS OF REINFORCEMENT OF NANOCOMPOSITES POLYURETHANE/CARBON NANOTUBE

The aim of present work is theoretical analysis of high values of reinforcement degree of nanocomposites polyurethane/carbon nanotube. For this two micromechanical models were used, showing identical results. The indicated models demonstrated, that densely-packed high-modulus interfacial regions, which serve the same reinforcing element of nanocomposite structure, as and nanofiller (carbon nanotubes) actually. The formation of interfacial regions defines by strong interactions polymer matrix – nanofiller. This means that nanofiller efficiency is controlled by its ability to generate densely-packed interfacial regions. It is important also to point out, that any micromechanical model, including mixtures rule, describes correctly modulus of elasticity of polymer nanocomposites, if in it real, but not nominal, characteristics of nanofiller were used. The content of interfacial regions in nanocomposite is controlled by structure of nanofiller. This allows to obtain important practical conclusion – for realization maximum degree of reinforcement it is necessary to cause structure of nanofiller, allowing to generate greatest content of interfacial regions. Absence of interfacial regions results to reduction of modulus of elasticity of nanocomposite in comparison with matrix polymer.