Effect of Bentonite on the Electrical Properties of a Polylactide-Based Nanocomposite.

In this paper, a novel polylactide-based nanocomposite with the addition of bentonite as a filler, Fusabond, and glycerine as a compatibilizer and plasticizer, were prepared and investigated. Four samples with different contents of bentonite (1, 5, 10, and 15 wt.%), as well as three samples without fillers, were prepared with an easily scalable method: melt blending. The electrical properties of all prepared samples were investigated with broadband dielectric spectroscopy in the frequency range between 0.1 Hz and 1 MHz. Measurements were conducted at nine temperatures between 293.15 and 333.15 K (20 to 60 °C) with steps of 5 K. It was found that the increase in the content of bentonite in polylactide has a significant effect on the electrical properties of the prepared nanocomposites.

Polymer Composites Based on Polycarbonate (PC) Applied to Additive Manufacturing Using Melted and Extruded Manufacturing (MEM) Technology.

As part of the present work, polymer composites used in 3D printing technology, especially in Melted and Extruded Manufacturing (MEM) technology, were obtained. The influence of modified fillers such as alumina modified silica, quaternary ammonium bentonite, lignin/silicon dioxide hybrid filler and unmodified multiwalled carbon nanotubes on the properties of polycarbonate (PC) composites was investigated. In the first part of the work, the polymer and its composites containing 0.5-3 wt.% filler were used to obtain a filament using the proprietary technological line. The moldings for testing functional properties were obtained with the use of 3D printing and injection molding techniques. In the next part of the work, the rheological properties-mass flow rate (MFR) and mechanical properties-Rockwell hardness, Charpy impact strength and static tensile strength with Young's modulus were examined. The structure of the obtained composites was also described and determined using scanning electron microscopy (SEM). The porosity, roughness and dimensional stability of samples obtained by 3D printing were also determined. On the other hand, the physicochemical properties were presented on the basis of the research results using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), wide angle X-ray scattering analysis (WAXS) and Fourier Transform infrared spectroscopy (FT-IR). Additionally, the electrical conductivity of the obtained composites was investigated. On the basis of the obtained results, it was found that both the amount and the type of filler significantly affected the functional properties of the composites tested in the study.

High AC and DC Electroconductivity of Scalable and Economic Graphite-Diamond Polylactide Nanocomposites.

Two types of graphite/diamond (GD) particles with different ash content was applied to prepare new electroconductive polylactide (PLA)-based nanocomposites. Four samples of nanocomposites for each type of GD particles with mass fraction 0.01, 0.05, 0.10, and 0.15 were prepared via an easily scalable method-melt blending. The samples were subjected to the studies of electrical properties via broadband dielectric spectroscopy. The results indicated up to eight orders of magnitude improvement in the electrical conductivity and electrical permittivity of the most loaded nanocomposites, in reference to the neat PLA. Additionally, the influence of ash content on the electrical conductivity of the nanocomposites revealed that technologically less-demanding fillers, i.e., of higher ash content, were the most beneficial in the light of nanofiller dispersibility and the final properties.

Thermal and Physical Characterization of PEG Phase Change Materials Enhanced by Carbon-Based Nanoparticles.

This paper presents the preparation and thermal/physical characterization of phase change materials (PCMs) based on poly(ethylene glycol) 400 g·mol-1 and nano-enhanced by either carbon black (CB), a raw graphite/diamond nanomixture (G/D-r), a purified graphite/diamond nanomixture (G/D-p) or nano-Diamond nanopowders with purity grades of 87% or 97% (nD87 and nD97, respectively). Differential scanning calorimetry and oscillatory rheology experiments were used to provide an insight into the thermal and mechanical changes taking place during solid-liquid phase transitions of the carbon-based suspensions. PEG400-based samples loaded with 1.0 wt.% of raw graphite/diamond nanomixture (G/D-r) exhibited the lowest sub-cooling effect (with a reduction of ~2 K regarding neat PEG400). The influences that the type of carbon-based nanoadditive and nanoparticle loading (0.50 and 1.0 wt.%) have on dynamic viscosity, thermal conductivity, density and surface tension were also investigated in the temperature range from 288 to 318 K. Non-linear rheological experiments showed that all dispersions exhibited a non-Newtonian pseudo-plastic behavior, which was more noticeable in the case of carbon black nanofluids at low shear rates. The highest enhancements in thermal conductivity were observed for graphite/diamond nanomixtures (3.3-3.6%), while nano-diamond suspensions showed the largest modifications in density (0.64-0.66%). Reductions in surface tension were measured for the two nano-diamond nanopowders (nD87 and nD97), while slight increases (within experimental uncertainties) were observed for dispersions prepared using the other three carbon-based nanopowders. Finally, a good agreement was observed between the experimental surface tension measurements performed using a Du Noüy ring tensiometer and a drop-shape analyzer.

Electrical and Optical Properties of Silicon OxideLignin Polylactide (SiO2-L-PLA).

This paper presents a study on the electrical properties of new polylactide-basednanocomposites with the addition of silicon-dioxide-lignin nanoparticles and glycerine as a plasticizer.Four samples were prepared with nanoparticle mass fractions ranging between 0.01 to 0.15(0.01, 0.05, 0.10, and 0.15), and three samples were prepared without nanoparticle filler-unfilledand unprocessed polylactide, unfilled and processed polylactide, and polylactide with Fusabondand glycerine. All samples were manufactured using the melt mixing extrusion techniqueand injection molding. Only the unfilled and unprocessed PLA sample was directly preparedby injection molding. Dielectric properties were studied with broadband spectroscopy in a frequencyrange from 0.1 Hz to 1 MHz in 55 steps designed on a logarithmic scale and a temperature rangefrom 293.15 to 333.15 K with a 5 K step. Optical properties of nanocomposites were measuredwith UV-VIS spectroscopy at wavelengths from 190 to 1100 nm. The experimental data show thatthe addition of silicon-dioxide-lignin and glycerine significantly affected the electrical propertiesof the studied nanocomposites based on polylactide. Permittivity and electrical conductivity showa significant increase with an increasing concentration of nanoparticle filler. The optical properties arealso affected by nanofiller and cause an increase in absorbance as the number of silicon-dioxide-ligninnanoparticles increase.

Electrical Conductivity and Dielectric Properties of Ethylene Glycol-Based Nanofluids Containing Silicon Oxide-Lignin Hybrid Particles.

This paper presents results of experimental investigation into dielectric properties of silicon oxide lignin (SiO2-L) particles dispersed with various mass fractions in ethylene glycol (EG). Measurements were conducted at a controlled temperature, which was changed from 298.15 to 333.15 K with an accuracy of 0.5 and 0.2 K for dielectric properties and direct current (DC) electrical conductivity, respectively. Dielectric properties were measured with a broadband dielectric spectroscopy device in a frequency range from 0.1 to 1 MHz, while DC conductivity was investigated using a conductivity meter MultiLine 3410 working with LR925/01 conductivity probe. Obtained results indicate that addition of even a small amount of SiO2-L nanoparticles to ethylene glycol cause a significant increase in permittivity and alternating current (AC) conductivity as well as DC conductivity, while relaxation time decrease. Additionally, both measurement methods of electrical conductivity are in good agreement.

Synthesis and electrochemical characterization of electroactive IoNanofluids with high dielectric constants from hydrated ferrous sulphate.

An iron oxide based-electroactive IoNanofluid with a high dielectric constant, high stability and low viscosity was synthesized from ferrous sulphate heptahydrate via a facile microwave assisted one-step route in 1-butyl-4-methylpyridinium chloride. The IoNanofluid exhibited CE coupled faradaic redox reactions involving reversible chemical reaction and reversible electron transfer steps. A transition from diffusion controlled to surface controlled capacitive processes was observed at varying scan rates. The efficiency of the charge-discharge process was greater than 94% even after 100 cycles.

Experimental Investigation of Electrical Conductivity and Permittivity of SC-TiO 2 -EG Nanofluids.

The paper presents experimental studies of dielectric properties of nanofluids based on ethylene glycol and SC-TiO2 nanoparticles with average size of 15-40 nm with various mass concentrations. The dielectric permittivity both real part and imaginary part as a function of temperature and frequency were measured. Also, dependence ac conductivity on frequency, temperature, and mass concentration were investigated. Based on the curves of ac conductivity, dc conductivity was calculated, and 400 % enhancement in dc conductivity was exposed.