scholarly journals Piezoelectric Films Based on Polyethylene Modified by Aluminosilicate Filler

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1345 ◽  
Author(s):  
Halina Kaczmarek ◽  
Bogusław Królikowski ◽  
Marta Chylińska ◽  
Ewa Klimiec ◽  
Dagmara Bajer
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Piezoelectric Materials ◽  
Constant Electric Field ◽  
Tensile Tests ◽  
Extrusion Process ◽  
X Ray Diffraction ◽  
Dispersed Filler ◽  
The Stability ◽  
Thermal Stability Of

The development, universality and miniaturization of electronic devices leads to the search for new piezoelectric materials, among which recently, polymers play an increasingly important role. In this work, composites based on two types of polyethylene—high density polyethylene (HDPE), and medium density polyethylene (MDPE)—and aluminosilicate fillers were obtained by extrusion process. This method allowed obtaining flexible electrets in the form of a thin film after polarization under a constant electric field of 100 V/μm. The morphology of the composites was characterized by scanning electron microscopy, whereas the crystallinity was determined by X-ray diffraction. The mechanical properties and thermal stability of the composites were examined by means of tensile tests and thermogravimetry, respectively. The piezoelectric characteristics were appointed by measuring the electric charge and the voltage in the polarized samples. Piezoelectric coefficients, and the stability of electrets over time were also determined. Moreover, the effect of film orientation on piezoelectric properties was investigated. Composites with appropriate morphology (i.e., well dispersed filler particles in the polymer matrix and formed holes) were obtained which ensured permanent electrical polarization. It was found that the best piezoelectric, mechanical properties and thermal stability exhibits HDPE composite with 5% of aluminosilicate filler.

Synthesis and Characterization of TiO2Nanoparticles with Polycarbonate and Investigation of its Mechanical Properties

2017 ◽  
Vol 16 (05n06) ◽  
pp. 1750012 ◽  
Author(s):  
Farhad Jahantigh ◽  
Mehdi Nazirzadeh
Keyword(s):  
Mechanical Properties ◽  
Weight Fraction ◽  
Xrd Analysis ◽  
Tensile Tests ◽  
Nanocomposite Films ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Stability Of

In this project, nanocomposite films were prepared with different Titanium dioxide (TiO2) percentages. Properties of polycarbonate (PC) and PC–TiO2nanocomposite films were studied by X-ray diffraction (XRD) analysis and Fourier transform infrared (FTIR) spectroscopy. The structure of samples was studied by XRD. The mechanical properties of PC–TiO2nanocomposite films were investigated by conducting tensile tests and hardness measurements. Thermal stability of the nanocomposites was studied by thermogravimetric analysis (TGA) method. The elastic modulus of the composite increased with increasing weight fraction of nanoparticles. The microhardness value increases with increasing TiO2nanoparticles. The results of tensile testing were in agreement with those of micro-hardness measurements. In addition, TGA curves showed that nanocomposite films have higher resistance to thermal degradation compared to polycarbonate. There are many reports related to the modification of polycarbonate films, but still a systematic study of them is required.

The Characterization of a New Antibacterial Polyurethane

2013 ◽  
Vol 750-752 ◽  
pp. 1609-1612 ◽  
Author(s):  
Yang Ti ◽  
Jian Ru Wu ◽  
Da Jun Chen
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Antibacterial Activity ◽  
Thermogravimetric Analysis ◽  
Shake Flask ◽  
Antibacterial Property ◽  
Tensile Tests ◽  
Thermal Stability Of

In this paper, Fe-OCAP/PU blends were prepared. The mechanical properties and thermal stability of the samples were studied by tensile tests and thermogravimetric analysis, respectively. Results showed that the mechanical properties and thermal stability of the samples were improved with the increase of Fe-OCAP content. The antibacterial property of Fe-OCAP and Fe-OCAP/PU films was investigated by agar diifusion method and shake flask method, respectively. Fe-OCAP and Fe-OCAP/PU films showed efficient antibacterial activity againstS.aureus.

scholarly journals Controlling the Thermal Stability of Kyanite-Based Refractory Geopolymers

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2903
Author(s):  
Juvenal Giogetti Nemaleu Deutou ◽  
Rodrigue Cyriaque Kaze ◽  
Elie Kamseu ◽  
Vincenzo M. Sglavo
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
High Strength ◽  
Treatment Temperature ◽  
Strength Development ◽  
Particle Sizes ◽  
Cold Setting ◽  
Thermal Stability Of ◽  
Geopolymer Composites ◽  
Refractory Composites

The present project investigated the thermal stability of cold-setting refractory composites under high-temperature cycles. The proposed route dealt with the feasibility of using fillers with different particle sizes and studying their influence on the thermo-mechanical properties of refractory geopolymer composites. The volumetric shrinkage was studied with respect to particle sizes of fillers (80, 200 and 500 µm), treatment temperature (1050–1250 °C) and amount of fillers (70–85 wt.%). The results, combined with thermal analysis, indicated the efficiency of refractory-based kyanite aggregates for enhancing thermo-mechanical properties. At low temperatures, larger amounts of kyanite aggregates promoted mechanical strength development. Flexural strengths of 45, 42 and 40 MPa were obtained for geopolymer samples, respectively, at 1200 °C, made with filler particles sieved at 80, 200 and 500 µm. In addition, a sintering temperature equal to 1200 °C appeared beneficial for the promotion of densification as well as bonding between kyanite aggregates and the matrix, contributing to the reinforcement of the refractory geopolymer composites without any sign of vitrification. From the obtained properties of thermal stability, good densification and high strength, kyanite aggregates are efficient and promising candidates for the production of environmentally friendly, castable refractory composites.

scholarly journals Mechanical and thermal stability of retained austenite in plastically deformed bainite-based TRIP-aided medium-Mn steels

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Aleksandra Kozłowska ◽  
Adam Grajcar ◽  
Aleksandra Janik ◽  
Krzysztof Radwański ◽  
Ulrich Krupp ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Retained Austenite ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Mechanical Stability ◽  
Electron Backscatter Diffraction ◽  
Cost Effective ◽  
Tensile Tests ◽  
Thermal Stability Of

AbstractAdvanced medium-Mn sheet steels show an opportunity for the development of cost-effective and light-weight automotive parts with improved safety and optimized environmental performance. These steels utilize the strain-induced martensitic transformation of metastable retained austenite to improve the strength–ductility balance. The improvement of mechanical performance is related to the tailored thermal and mechanical stabilities of retained austenite. The mechanical stability of retained austenite was estimated in static tensile tests over a wide temperature range from 20 °C to 200 °C. The thermal stability of retained austenite during heating at elevated temperatures was assessed by means of dilatometry. The phase composition and microstructure evolution were investigated by means of scanning electron microscopy, electron backscatter diffraction, X-ray diffraction and transmission electron microscopy techniques. It was shown that the retained austenite stability shows a pronounced temperature dependence and is also stimulated by the manganese addition in a 3–5% range.

Intrinsic Thermal Stability of Anisotropic Thin-Film Superconductors

1990 ◽  
Vol 112 (1) ◽  
pp. 10-15 ◽  
Author(s):  
M. I. Flik ◽  
C. L. Tien
Keyword(s):  
Thin Film ◽  
Thermal Stability ◽  
Stability Criterion ◽  
High Temperature Superconductors ◽  
Stability Criteria ◽  
Anisotropic Thermal Conductivity ◽  
Operating Current ◽  
Released Energy ◽  
The Stability ◽  
Thermal Stability Of

Intrinsic thermal stability denotes a situation where a superconductor can carry the operating current without resistance at all times after the occurrence of a localized release of thermal energy. This novel stability criterion is different from the cryogenic stability criteria for magnets and has particular relevance to thin-film superconductors. Crystals of ceramic high-temperature superconductors are likely to exhibit anisotropic thermal conductivity. The resultant anisotropy of highly oriented films of superconductors greatly influences their thermal stability. This work presents an analysis for the maximum operating current density that ensures intrinsic stability. The stability criterion depends on the amount of released energy, the Biot number, the aspect ratio, and the ratio of the thermal conductivities in the plane of the film and normal to it.

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