scholarly journals Creation of low-thermal-conductivity polymer nanocomposites for internal gas vents of boiler chimneys

2020 ◽  
pp. 57-68
Author(s):  
N. Fialko ◽  
◽  
R. Dinzhos ◽  
V. Prokopov ◽  
Ju. Sherenkovsky ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Polymer Nanocomposites ◽  
Conducting Polymer ◽  
Heat Conductivity ◽  
Young's Modulus ◽  
Structural Characteristics ◽  
Experimental Studies ◽  
Polymer Melt ◽  
Heat Conducting ◽  
Scanning Calorimetry

Methods and results of experimental studies of thermophysical, structural and mechanical properties of low-heat-conducting polymer nanocomposites, oriented to use for gas ducts and chimneys of boiler installations, as well as various other gas and water communications are presented. In this work, on the basis of the performed set of methodological studies regarding the analysis of the legitimacy of using different models of heat conductivity for predicting the heat-conducting properties of these composites, the possibility of using for this prediction a number of models of the theory of the effective medium and the theory of percolation is considered. The analysis of thermophysical properties, structural characteristics and Young's modulus of low-heat-conductivity polymer nanocomposites based on polyethylene and polypropylene is carried out. Using these nanocomposites as an example, the achievement of a significant increase in their Young's modulus in comparison with unfilled polymers with a relatively small increase in heat conductivity is demonstrated. To obtain nanocomposites, we used a method based on mixing the components in a polymer melt using an extruder and then shaping the composite into the required shape by hot pressing. The method of differential scanning calorimetry was used to determine Young's modulus. On the basis of the studies carried out, the possibility of obtaining low-heat-conducting polymer nanocomposites with improved mechanical characteristics has been shown. In particular, it was shown that for nanocomposites based on polyethylene or polypropylene filled with CNTs (carbon nanotubes) or nanodispersed aerosil particles, with a mass fraction of the latter up to 2%, the following takes place a relatively insignificant increase in heat conductivity coefficients and a significant increase in the modulus of elasticity in tension. The research data also made it possible to obtain for the developed nanocomposites the temperature dependences of their specific mass heat capacity and, on this basis, to analyze the regularities of changes in the structural characteristics of these materials.

STUDIES OF THE INFLUENCE ON THE HEAT-CONDUCTING PROPERTIES OF NANOCOMPOSITES OF THE TEMPERATURE REGIME OF THEIR PREPARATION

2017 ◽  
Author(s):  
Nataliia Fialko ◽  
◽  
Roman Dinzhos ◽  
Viktor Prokopov ◽  
Julii Sherenkovskiy ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Melting Temperature ◽  
Temperature Regime ◽  
Heat Conductivity ◽  
Experimental Studies ◽  
Polymer Melt ◽  
Heat Conducting ◽  
Heat Conductivity Coefficient

The results of experimental studies of the dependence of the heat conductivity of nanocomposites based on polypropylene filled with carbon nanotubes on the level of overheating of the polymer melt relative to its melting temperature are presented. It was found that with an increase in this level, the value of the heat conductivity coefficient of composites increases. It is shown that when a certain overheating is reached, its further growth does not provide an increase in the heat conductivity of nanocomposites. On the basis of the obtained regularity, the value of the rational level of overheating was determined.

A UNIQUE APPROACH TO EXPERIMENTAL CHARACTERIZATION OF A THERMOSETTING POLYMER MATRIX FOR ICME FRAMEWORKS

2021 ◽  
Author(s):  
MICHAEL N. OLAYA ◽  
SAGAR PATIL ◽  
GREGORY M. ODEGARD ◽  
MARIANNA MAIARÙ
Keyword(s):  
Tensile Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Cure Kinetics ◽  
Image Correlation ◽  
Scanning Calorimetry ◽  
Mixing Ratios ◽  
Fitting Procedure ◽  
Amine Content

A novel approach for characterization of thermosetting epoxy resins as a function of the degree of cure is presented. Density, cure kinetics, tensile strength, and Young’s modulus are experimentally characterized across four mixing ratios of DGEBF/DETDA epoxy. Dynamic differential scanning calorimetry (DSC) is used to characterize parameters for a Prout-Thompkins kinetic model unique to each mixing ratio case through a data fitting procedure. Tensile strength and Young’s modulus are then characterized using stress-strain data extracted from quasi-static, uniaxial tension tests at room temperature. Strains are measured with the 2-D digital image correlation (DIC) optical strain measurement technique. Strength tends to increase as amine content use in the formulation increases. The converse trend is observed for Young’s modulus. Density measurements also reveal an inverse relationship with amine content.

Assumption of interphase properties in classical Christensen–Lo model for Young's modulus of polymer nanocomposites reinforced with spherical nanoparticles

RSC Advances ◽  
2015 ◽  
Vol 5 (116) ◽  
pp. 95532-95538 ◽  
Author(s):  
Yasser Zare
Keyword(s):  
Young’S Modulus ◽  
Polymer Nanocomposites ◽  
Young's Modulus ◽  
Spherical Nanoparticles ◽  
Classical Models

The significant reinforcement of polymer nanocomposites containing spherical nanoparticles which exceeds the predictions of classical models is commonly attributed to the formation of an interphase between polymer and nanoparticles.

Influence of annealing on microstructure & molecular orientation, thermal behaviour, mechanical properties and their correlations of uniaxially drawn iPP thin film

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Sayant Saengsuwan
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Thermal Behaviour ◽  
Annealing Time ◽  
Molecular Orientation ◽  
Young's Modulus ◽  
Crystal Thickness ◽  
Scanning Calorimetry

AbstractThe influence of annealing on the microstructure and molecular orientation, thermal behaviour and mechanical properties of uniaxially drawn iPP thin film was studied by wide-angle X-ray diffraction, differential scanning calorimetry and tensile testing, respectively. The correlations of mechanical and microstructural properties of annealed films were also examined. The transformation of smectic phase of iPP to the α-form was more pronounced with increasing annealing time and temperature. The true and apparent crystallinities and crystal thickness were strongly enhanced with annealing time and temperature. The relative molecular orientation tended to increase with annealing time. These results caused the significant improvement of modulus and tensile strength of the annealed films in both machine (MD) and transverse (TD) directions. The increases in MD-Young’s modulus and MD-tensile strength were well correlated with the increase in true crystallinity obtained in equatorial scans. Some relationship between the increase in crystal thickness and the increase in Young’s modulus in both MD and TD directions was also found.

Room-Temperature Mechanical Characterization of Bulk Glassy and Partially Crystallized Zr63Al9.7Ni9.7Cu14.6Nb3 Alloys

2009 ◽  
Vol 633-634 ◽  
pp. 675-683
Author(s):  
F.W. Li ◽  
Jian Bing Qiang ◽  
S.G. Quan ◽  
Qing Wang ◽  
Chuang Dong ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Room Temperature ◽  
Young's Modulus ◽  
Cast Alloy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Plastic Deformation Process ◽  
Icosahedral Quasicrystals ◽  
Constant Heating

The microstructures and mechanical behavior of the as-cast and isothermally annealed Zr63Al9.7Ni9.7Cu14.6Nb3 bulk metallic glasses (BMGs) were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), and room temperature uniaxial compression. The as-cast BMG alloy shows a wide undercooled liquid span of 73 K at a constant heating rate of 40 K/min. Composite microstructures containing nanometer scaled icosahedral quasicrystals (i-phase) were produced upon annealing at 705 K. Under uniaxial room-temperature compression at a strain rate of 510-4 s-1, the as-cast BMG alloy exhibits a elastic deformation εy ~ 1.95%, a yield stress σy ~ 1650 MPa, and a Young’s modulus E ~ 84.5 GPa. The alloy shows a plastic strain εp ~ 8.0 % in a serrated plastic deformation process. Annealing induced embrittlement was observed in the relaxed BMG alloys. Comparing with the as-cast alloy, the relaxed and the composite alloys show negligible changes in elastic strain and Young’s modulus. The partially crystallized alloys are macroscopically brittle. Well developed vein patterns were observed in the fracture surfaces of all these alloys. The present work revealed that the dispersion of nanometer scaled i-phase particles is not effective as a barrier against shear localization in these partially quasicrystallized alloys.

Sensitivity of lightweight deflectometer deflections to layer stiffness via finite element analysis

2015 ◽  
Vol 52 (7) ◽  
pp. 961-970 ◽  
Author(s):  
Christopher T. Senseney ◽  
Jacob Grasmick ◽  
Michael A. Mooney
Keyword(s):  
Finite Element ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Experimental Studies ◽  
Fe Model ◽  
Element Analysis ◽  
Soil System ◽  
Dynamic Finite Element ◽  
Back Calculation ◽  
Measurement Depth

A dynamic finite element (FE) model of lightweight deflectometer (LWD) loading on a two-layer soil system, validated with an analytical solution and experimental data, is presented. Peak dynamic FE vertical deflections can be substantially different (almost always smaller) than FE static deflections. The numerically simulated measurement depth of the LWD center sensor is found to be 2–2.5 times the plate diameter, deeper than other experimental studies. Using the FE model, we conduct a sensitivity analysis of peak vertical deflections to the top layer Young’s modulus and underlying Young’s modulus of two-layer systems. Peak deflections from the center sensor are found to be more sensitive to the top layer Young’s modulus while peak deflections at radial offsets are found to be more sensitive to the underlying layer Young’s modulus. Sensitivities of layer moduli to FE deflections offer guidance in selecting weighting factors for the inverse solver in an LWD back-calculation procedure.

Effect of compatibilizing agents on the physical properties of iPP/HDPE organoclay blends

2013 ◽  
Vol 33 (7) ◽  
pp. 589-598 ◽  
Author(s):  
Samia Boufassa ◽  
R. Doufnoune ◽  
Abdelhak Hellati ◽  
Nacceredine Haddaoui ◽  
M. Esperanza Cagiao
Keyword(s):  
Maleic Anhydride ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
The One ◽  
Grafted Epdm ◽  
The Relationship ◽  
Butadiene Styrene

Abstract Blends of isotactic polypropylene (iPP) and high density polyethylene (HDPE), with and without compatibilizers and with different organoclay amounts (1%, 3%, and 5%), were systematically investigated to assess the effect of the additives on the crystallinity of the blends, as well as the correlation between the microhardness, H and the Young’s modulus E. The compatibilizers used were: maleic anhydride grafted styrene ethylene butadiene styrene (SEBS-g-MAH), maleic anhydride grafted polyethylene (PE-g-MAH), maleic anhydride grafted polypropylene (PP-g-MAH), ethylene propylene diene monomer (EPDM), and maleic anhydride grafted EPDM (EPDM-g-MAH). The thermal properties and crystallization behavior were determined by differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS). Macro- and micromechanical properties were also investigated. The results obtained showed that the addition of clay slightly increases the crystallinity αWAXS of the blends. However, the hardness H decreases enormously only by adding 1 wt% of clay. With higher clay amounts, H increases again. The relationship between the Young’s modulus E and the hardness H for all the studied blends was found to be somewhat higher than the one obtained for polyethylene (PE) samples with different morphologies.

Recycled HDPE-tetrapack composites. Isothermal crystallization, light scattering and mechanical properties

2012 ◽  
Vol 1485 ◽  
pp. 77-82 ◽  
Author(s):  
A Parada-Soria ◽  
HF Yao ◽  
B Alvarado-Tenorio ◽  
L Sanchez-Cadena ◽  
A Romo-Uribe
Keyword(s):  
Mechanical Properties ◽  
Light Scattering ◽  
Young’S Modulus ◽  
Tensile Deformation ◽  
Young's Modulus ◽  
Ultimate Tensile Stress ◽  
Uniaxial Tensile ◽  
Scanning Calorimetry ◽  
Slow Cooling ◽  
The Matrix

ABSTRACTIn this research the thermal and mechanical properties of composites based on recycled high-density polyethylene (HDPE) and recycled Tetrapak have been investigated. The matrix and filler are recovered from landfills. Multicolor HDPE mixtures, with varying concentration of tetrapack flakes, are hot pressed, as well as single color HDPE flakes. Previous studies determine that the nature of the pigment (organics vs. inorganics) strongly influence the mechanical behavior of multicolor HDPE-tetrapack composites. Thus, this research focuses on single color HDPE hot pressed plaques. The kinetics of crystallization under isothermal conditions is determined by differential scanning calorimetry (DSC). The results show that the crystallization kinetics obeys the Avrami theory, and that the Avrami exponent is 1, irrespective of the pigment in use. Small-angle light scattering is applied to investigate the internal structure of the pigmented HDPE. SALS patterns show that the samples exhibited oriented morphologies. However, after melting and slow cooling under pressure the samples exhibit an isotropic morphology. This is confirmed by polarized optical microscopy. Mechanical properties such as Young’s modulus, yield stress and ultimate tensile stress are obtained under uniaxial tensile deformation at room temperature. For the single color HDPE plaques the Young’s modulus is reduced (after melting), suggesting that the anisotropic molecular chains contribute to the higher value of Young’s modulus.

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