A study on the progress of mutarotation above and below the Tg and the relationship between constant rates and structural relaxation times

2017 ◽  
Vol 19 (31) ◽  
pp. 20949-20958 ◽  
Author(s):  
K. Wolnica ◽  
M. Dulski ◽  
E. Kaminska ◽  
A. Cecotka ◽  
M. Tarnacka ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Structural Relaxation ◽  
Relaxation Times ◽  
Ftir Studies ◽  
Wide Range ◽  
The Relationship

Comprehensive FTIR studies on the progress of mutarotation in d-fructose mixed with maltitol have been carried out over a wide range of temperatures, both above and below the glass transition temperature Tg.

scholarly journals Reduced Glass-Transition Temperature versus Glass-Forming Ability in FeCoB-Based Amorphous Alloys

2016 ◽  
Vol 61 (4) ◽  
pp. 1957-1962 ◽  
Author(s):  
M. Nabiałek
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Glass Forming Ability ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Glass Forming ◽  
Wide Range ◽  
Temperature Ranges ◽  
The Relationship

AbstractThis work presents studies concerning the relationship between reduction of glass transition temperatureTrgand the glass-forming ability of FeCoB-based alloys. On the basis of theoretical considerations, Turnbull [1] determined the reduced glass transition temperature (Tg/Tl) as being 2/3 of the Vogel–Fulcher–Tammann (VFT) temperature; since then, continuous research has been carried out, aiming to calculate the Trg parameter and describe its relationship with glass-forming ability. In the majority of research papers, the reduced glass transition temperature is calculated from the relationshipTg/Tm, proposed by Uhlmann and Davies [2, 3]. On the basis of differential scanning calorimetry (DSC) studies, undertaken in this current work, the values of the following temperatures have been found:Tg,Tx, Tmand Tl, in addition to the temperature ranges:ΔTx,ΔTmandΔTl. The correlation between:Tg/Tm,Tg/Tland the glass-forming ability also has been discussed. Finally, for the investigated alloys, it has been found that the relationship proposed by Turnbull is reliable over a wide range ofΔTm.

scholarly journals Effects of Annealing on Enthalpy Recovery and Nanomechanical Behaviors of a La-Based Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 579
Author(s):  
Ting Shi ◽  
Lanping Huang ◽  
Song Li
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Structural Relaxation ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Nanoindentation Measurement

Structural relaxation and nanomechanical behaviors of La65Al14Ni5Co5Cu9.2Ag1.8 bulk metallic glass (BMG) with a low glass transition temperature during annealing have been investigated by calorimetry and nanoindentation measurement. The enthalpy release of this metallic glass is deduced by annealing near glass transition. When annealed below glass transition temperature for 5 min, the recovered enthalpy increases with annealing temperature and reaches the maximum value at 403 K. After annealed in supercooled liquid region, the recovered enthalpy obviously decreases. For a given annealing at 393 K, the relaxation behaviors of La-based BMG can be well described by the Kohlrausch-Williams-Watts (KWW) function. The hardness, Young’s modulus, and serrated flow are sensitive to structural relaxation of this metallic glass, which can be well explained by the theory of solid-like region and liquid-like region. The decrease of ductility and the enhancement of homogeneity can be ascribed to the transformation from liquid-like region into solid-like region and the reduction of the shear transition zone (STZ).

A facile route to well-defined imidazolium-based poly(ionic liquid)s of enhanced conductivity via RAFT

2017 ◽  
Vol 8 (35) ◽  
pp. 5433-5443 ◽  
Author(s):  
Paulina Maksym ◽  
Magdalena Tarnacka ◽  
Andrzej Dzienia ◽  
Karol Erfurt ◽  
Anna Chrobok ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ionic Liquid ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Temperature Conductivity ◽  
Poly Ionic Liquid ◽  
The Relationship ◽  
Enhanced Conductivity ◽  
Facile Route

Examining the relationship between the glass transition temperature, conductivity and molecular weight of tailored imidazolium-based PILs synthesized via RAFT.

scholarly journals The Glass Transition Temperature and Temperature Dependence of Activation Energy of Viscous Flow of Ovalbumin

2016 ◽  
Vol 39 (1) ◽  
pp. 13-25
Author(s):  
Karol Monkos
Keyword(s):  
Activation Energy ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Viscous Flow ◽  
Solvent Interactions ◽  
Model Free ◽  
Free Volume Model ◽  
Wide Range ◽  
Different Temperatures

Abstract The paper presents the results of viscosity determinations on aqueous solutions of ovalbumin at a wide range of concentrations and at temperatures ranging from 5°C to 55°C. On the basis of these measurements and three models of viscosity for glass-forming liquids: Avramov’s model, free-volume model and power-law model, the activation energy of viscous flow for solutions and ovalbumin molecules, at different temperatures, was calculated. The obtained results show that activation energy monotonically decreases with increasing temperature both for solutions and ovalbumin molecules. The influence of the energy of translational heat motion, protein-protein and protein-solvent interactions, flexibility and hydrodynamic radius of ovalbumin on the rate of decrease in activation energy with temperature has been discussed. One of the parameters in the Avramov’s equation is the glass transition temperature Tg. It turns out that the Tg of ovalbumin solutions increases with increasing concentration. To obtain the glass transition temperature of the dry ovalbumin, a modified Gordon-Taylor equation is used. Thus determined the glass transition temperature for dry ovalbumin is equal to (231.8 ± 6.1) K.

The Influence of Gamma Radiation on the Glass Transition of Hydroxyapatite/Poly L-Lactide Composite

2007 ◽  
Vol 555 ◽  
pp. 497-502
Author(s):  
Dejan Miličević ◽  
S. Trifunović ◽  
N. Ignjatović ◽  
E. Suljovrujić
Keyword(s):  
Activation Energy ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Structural Relaxation ◽  
Absorbed Dose ◽  
Gel Permeation Chromatography ◽  
Chain Scission ◽  
Scanning Calorimetry ◽  
Dsc Measurements

Hydroxyapatite/poly L-lactide (HAp/PLLA) is a composite biomaterial which has been widely utilized for substitution and reparation of the hard bone tissue. It is well known that gamma irradiation has been successfully employed in the modification/sterilization of such porous composites and that it has advantages over other procedures. In this study, differential scanning calorimetry (DSC) measurements were made to investigate the influence of the radiation on glass transition behavior and structural relaxation, as well as to estimate the activation energy for this process. The apparent activation energy ΔH* for structural relaxation in the glass transition region was determined on the basis of the heating rate dependence of the glass transition temperature Tg. Furthermore, the results were correlated with those obtained by gel permeation chromatography (GPC). Our findings support the fact that the radiation-induced chain scission in the PLLA phase is the main reason for the decrease of the glass transition temperature and/or activation energy with the absorbed dose.

Sign in / Sign up

Export Citation Format

Share Document