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Incorporation of conductive carbon fillers into polymer matrices can improve the electrical, thermal and mechanical properties of the resulting composites. In this work, three different conductive carbon fillers size were used: graphite (microfiller), graphite nano-platelets (GNP) and as-received multiwall carbon nanotubes (A-MWCNTs) as nanofiller. These three fillers were incorporated into polyethylene terephthalate (PET) to prepare four types of PET/carbon micro- and nano-composites. These composites were prepared by meltcompounding using a Haake Minilab extruder equipped with co-rotating twin screws. The extruded samples were compression-moulded to films of 1 mm thickness. The effect of those carbon fillers on the electrical properties of PET was investigated. The PET/AMWCNTs composites exhibited an excellent electrical conductivity with a low percolation threshold (Φ_c ~ 0.33 wt. % of carbon nanotubes [CNTs]) compared to other investigated PET/carbon composites.

The human environment is at high risk of contamination by the extensive use of non-degradable resources as well as exhaustion of naturally available resources. To combat the environmental and energy issues, recent developments in nanotechnology have open gateways for the sustainable development of eco-friendly, biodegradable, and renewable polymeric materials. Nanocellulose, possessing unique features such as fibrous structure, high mechanical strength, large surface area, low visual scattering, low-cost, renewability, non-toxicity, biocompatibility, and easy availability, serves as an ideal material for diverse environmental applications. In addition, its unique three-dimensional fibril arrangement allows the impregnation of variety of nanosize materials to enable the development of nanocomposites in the form of hydrogels, aerogels, and films, papers, or membranes. Such substrates serve as templates for inorganic nanoparticles and polymers, or a combination of both. Such unique features make nanocellulose-based materials more efficient, robust, stable, reliable, and environmentally-friendly, thus enabling it to find potential applications in the development of antimicrobial filters and devices for removal of heavy metals, in water treatment and wastewaters purification, in the development of pollutant sensors, as well as in potential applications in catalysis and renewable energy. This chapter provides a comprehensive picture of the recent developments in nanocellulose-based materials to address various issues associated with environment and renewable energy.

Polypropylene/poly (butylene terephthalate) (PP/PBT) blends containing organo-montmorillonite (OMMT) were prepared using a twin-screw extruder. Aim of this work was to study the morphology and properties of PP/PBT/OMMT composites. The weight ratio of PP to PBT was kept at 70:30, while the weight fraction of the OMMT was varied from 0 to 7 wt%. The OMMT dispersion was evaluated by transmission electron microscopy (TEM) and the phase morphology of composites was evaluated by scanning electronic microscopy (SEM). The results showed that the OMMT layers were mainly intercalated and well dispersed in the PP/PBT matrix. The thermal properties, mechanical properties and rheological behavior of PP/PBT/OMMT composites were also evaluated.

We study the noise spectra and high-frequency permeability of inhomogeneous magnetic materials consisting of single-domain magnetic nanoparticles embedded into an insulating matrix. Possible mechanisms of 1/f voltage noise in phase-separated manganites is analyzed. The material is modelled by a system of small ferromagnetic metallic droplets (magnetic polarons or ferrons) in insulating antiferromagnetic or paramagnetic matrix. The electron transport is related to tunnelling of charge carriers between droplets. One of the sources of the 1/f noise in such a system stems from fluctuations of the number of droplets with extra electron. In the case of strong magnetic anisotropy, the 1/f noise can arise also due to the fluctuations of the magnetic moments of ferrons.

The high frequency magnetic permeability of nanocomposite film with magnetic particles in insulating non-magnetic matrix is studied in detail. The case of strong magnetic dipole interaction and strong magnetic anisotropy of ferromagnetic granules is considered. The composite is modelled by a cubic regular array of ferromagnetic particles. The high-frequency permeability tensor components are found as a functions of frequency, temperature, ferromagnetic phase content, and magnetic anisotropy. The results demonstrate that magnetic dipole interaction leads to a shift of the resonance frequencies towards higher values, and nanocomposite film could have rather high value of magnetic permeability in the microwave range.

Extensive numerical simulation and experimental measurements have been conducted to understand the piezoresistivity characteristics and the working mechanisms of highly sensitive strain sensors made from carbon nanotubes (CNTs) embedded polymer nanocomposites. When using two kinds of multi-walled carbon nanotubes (MWNTs), it was identified that the piezoresistivity characteristics of two sensors are different. When using comparatively straight MWNTs of a large diameter, named as MWNT-7, the fundamental working mechanism of this sensor is the tunneling resistance change among CNTs due to the distance change caused by applied strains. However, for another type of MWNTs, which is of a very small diameter and seriously curved shapes, and named as LMWNT-10, the main working mechanism of the sensor may be the piezoresistivity of MWNTs themselves due to deformation of MWNTs. Furthermore, for the sensors made from MWNT-7/epoxy, further numerical and experimental investigations have been carried out to explore the effects of processing parameters and material properties on sensor sensitivity. Both numerical and experimental results indicate that a higher tunneling resistance or higher ratio of the tunneling resistance to the total resistance of the sensor leads to a higher sensor sensitivity. Processing conditions and material properties play a role in determining the sensor sensitivity.

Nanoflower-like hollow carbon sphere (CS) materials with two different heteroatoms doping (N, P) were prepared by a simple synthetic method (NPCS). The specific surface area of NPCS can reach a high value of 396 m²/g. The NPCS has a high degree of hollowness and the self-assembled nanosheet of NPCS forms a fast electron transport channel, and also increases active area in contact with electrolyte. The doping of heteroatoms increases the defect level of the carbon-based nanomaterials and changes the local electron state of the material, thus forming storage sites on the surface of the material, which can be used as a station for ions collecting and distributing. The material was studied as an active material for supercapacitors, and the specific capacitance reached 274.9 F/g. After the 4000th cycle stability test, it still maintained 95.2% of the specific capacitance, indicating that the material has excellent properties of supercapacitor materials.