Composition dependence of thermo-dynamical and thermo-mechanical properties in SeTeSnGe chalcogenide glasses (ChGs)

2020 ◽  
Vol 90 (3) ◽  
pp. 31101
Author(s):  
Shiv Kumar Pal ◽  
Neeraj Mehta ◽  
John C. MacDonald ◽  
Dipti Sharma
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Specific Heat ◽  
Molar Volume ◽  
Chalcogenide Glasses ◽  
Composition Dependence ◽  
Glass Transition Region ◽  
Scanning Calorimetry ◽  
Heat Value ◽  
Large Increment

In this endeavor, we have synthesized novel quaternary glassy Se78-xTe20Sn2Gex (0 ≤ x ≤ 6) alloys by the well-known rapid cooling of melt under quenching technique, to study the effect of Germanium on thermodynamic and thermo-mechanical properties. In particular, we employed Differential Scanning Calorimetry (DSC) technique for the investigation of thermodynamic parameters (e.g., specific heat Cp and enthalpy ΔH) in the glass-transition-region (GTR). Differential Scanning Calorimetry (DSC) experiment was run under non-isothermal conditions. The thermo-mechanical parameters i.e., micro-hardness, micro-void volume, the energy of creation of micro-void, elasticity, density, compactness, and molar volume are also calculated. It was observed that there is a large increment in Cp values in the GTR. Further analysis shows that the Cp values above the GTR (i.e., Cp  = Cpe equilibrium specific heat) and below the GTR (i.e., Cp  = Cpg glass specific heat) are vastly composition dependent. The increment in specific heat value after Ge incorporation is explained in terms of molar volume.

Glass transformation, heat capacity, and structure of GexSe100−x glasses studied by temperature-modulated differential scanning calorimetry experiments

1997 ◽  
Vol 12 (7) ◽  
pp. 1892-1899 ◽  
Author(s):  
T. Wagner ◽  
S. O. Kasap ◽  
Kouji Maeda
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Heat Flow ◽  
Chalcogenide Glasses ◽  
Glass Transition Region ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Heat Flows ◽  
Glass Transformation

The recent novel temperature-modulated differential scanning calorimetry (DSC) (MDSCTM TA Instruments) technique has been applied to characterize the thermal properties of Ge–Se chalcogenide glasses in the glass transition region. All samples in this work were given the same thermal history by heating to a temperature above the glass transition, equilibrating, and then cooling at a rate of 5 °C/min to a temperature of 20 °C. The reversing and nonreversing heat flows through the glass transformation region during both heating and cooling schedules were measured, and the values of the parameters Tg, ΔH, Cp, and ΔCp, which characterize the thermal events in the glass transition region, were determined. The ability of determining the reversible heat flow in MDSC enables an accurate measurement of the true heat capacity (that normally associated with reversible heat flow), which could not be done hitherto in conventional thermal analysis where the detected heat flow is the total heat flow, the sum of reversing and nonreversing heat flows. The structurally controlled parameters Tg, ΔH, Cp, and ΔCp reveal extrema when the Ge–Se glass system reaches the average coordination number 〈r〉 = 2.67 at 33.3 at.% Ge which corresponds to the stoichiometric composition GeSe2. We also observed extrema in the composition dependence of the above thermal parameters at 20.0 and 40.0 at.% Ge which correspond to stoichiometric compositions GeSe4 and Ge2Se3 with average coordination numbers 2.40 and 2.80, respectively. No such clear local maxima below and above the 33.3 at.% Ge composition could be observed previously in thermal analysis. We compare our MDSC results with previously published works on glass transition in Ge–Se glasses and discuss the results in terms of recent structural models for chalcogenide glasses.

Research on compatibility and surface of high impact bio-based polyamide

2021 ◽  
pp. 095400832110055
Author(s):  
Yang Wang ◽  
Yuhui Zhang ◽  
Yuhan Xu ◽  
Xiucai Liu ◽  
Weihong Guo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
High Impact ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

The super-tough bio-based nylon was prepared by melt extrusion. In order to improve the compatibility between bio-based nylon and elastomer, the elastomer POE was grafted with maleic anhydride. Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA) were used to study the compatibility and micro-distribution between super-tough bio-based nylon and toughened elastomers. The results of mechanical strength experiments show that the 20% content of POE-g-MAH has the best toughening effect. After toughening, the toughness of the super-tough nylon was significantly improved. The notched impact strength was 88 kJ/m2 increasing by 1700%, which was in line with the industrial super-tough nylon. X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to study the crystallization behavior of bio-based PA56, and the effect of bio-based PA56 with high crystallinity on mechanical properties was analyzed from the microstructure.

Physico Chemical Characterization of Nanofibrous Poly(Ε-Caprolactone) Electrospun Templates for Cell Adhesion

MRS Advances ◽  
2017 ◽  
Vol 2 (49) ◽  
pp. 2689-2694
Author(s):  
Karla A. Gaspar-Ovalle ◽  
Juan V. Cauich-Rodriguez ◽  
Armando Encinas
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Cell Adhesion ◽  
Tensile Modulus ◽  
Chemical Characterization ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Physico Chemical ◽  
Static Water

ABSTRACTNanofibrous mats of poly ε-caprolactone (PCL) were fabricated by electrospinning. The nanofiber structures were investigated and characterized by scanning electron microscope, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, static water-contact-angle analysis and mechanical properties. The results showed that the nanofibrous PCL is an ideal biopolymer for cell adhesion, owing to its biocompatibility, biodegradability, structural stability and mechanical properties. Differential scanning calorimetry results showed that the fibrous structure of PCL does not alter its crystallinity. Studies of the mechanical properties, wettability and degradability showed that the structure of the electrospun PCL improved the tensile modulus, tensile strength, wettability and biodegradability of the nanotemplates. To evaluate the nanofibrous structure of PCL on cell adhesion, osteoblasts cells were seeded on these templates. The results showed that both adhesion and proliferation of the cells is viable on these electrospun PCL membranes. Thus electrospinning is a relatively inexpensive and scalable manufacturing technique for submicron to nanometer diameter fibers, which can be of interest in the commodity industry.

Specific heats of polymer powders by differential scanning calorimetry

1982 ◽  
Vol 60 (14) ◽  
pp. 1853-1856 ◽  
Author(s):  
Eva I. Vargha-Butler ◽  
A. Wilhelm Neumann ◽  
Hassan A. Hamza
Keyword(s):  
Differential Scanning Calorimetry ◽  
Specific Heat ◽  
Scanning Calorimetry ◽  
Temperature Range ◽  
Specific Heats ◽  
Powdered Form ◽  
Polymer Powders

The specific heats of five polymers were determined by differential scanning calorimetry (DSC) in the temperature range of 300 to 360 K. The measurements were performed with polymers in the form of films, powders, and granules to clarify whether or not DSC specific heat values are dependent on the diminution of the sample. It was found that the specific heats for the bulk and powdered form of the polymer samples are indistinguishable within the error limits, justifying the determination of specific heats of powders by means of DSC.

Sign in / Sign up

Export Citation Format

Share Document