The glass transition and crystallization of propylene carbonate investigated by mechanical spectroscopy

2013 ◽  
Vol 88 (2) ◽  
pp. 025603 ◽  
Author(s):  
X N Ying
Keyword(s):  
Glass Transition ◽  
Propylene Carbonate ◽  
Mechanical Spectroscopy

APPLICATION OF REED-VIBRATION MECHANICAL SPECTROSCOPY FOR LIQUIDS IN STUDYING LIQUID CRYSTALLIZATION

2013 ◽  
Vol 27 (21) ◽  
pp. 1350080 ◽  
Author(s):  
HENG-WEI ZHOU ◽  
LI-NA WANG ◽  
LI-LI ZHANG ◽  
YI-NENG HUANG
Keyword(s):  
Glass Transition ◽  
Room Temperature ◽  
Crystallization Process ◽  
Volume Fraction ◽  
Supercooled Liquid ◽  
Avrami Exponent ◽  
Dimethyl Phthalate ◽  
Mechanical Spectroscopy ◽  
Crystal Volume ◽  
Complex Young’S Modulus

By using the reed-vibration mechanical spectroscopy for liquids (RMS-L), we measured the complex Young's modulus of dimethyl phthalate (DP) during a cooling and heating circulation starting from room temperature at about 2 KHz. The results show that there is no crystallization in the cooling supercooled liquid (CSL) of DP, but a crystallization process in the heating supercooled liquid (HSL) after the reverse glass transition. Based on the measured modulus, crystal volume fraction (v) during the HSL crystallization was calculated. Moreover, the Avrami exponent (n) was obtained according to the JJMA equation and v data. In view of n versus temperature and v, the nucleation dynamics was analyzed, and especially, there has already existed saturate nuclei in DP HSL before the crystallization. Furthermore, the authors inferred that the nuclei are induced by the random frozen stress in the glass, but there is no nucleus in CSL. The above results indicated that RMS-L might provide a new way to measure and analyze the crystallization of liquids.

scholarly journals Light-scattering study of the liquid-glass transition in propylene carbonate

1994 ◽  
Vol 49 (3) ◽  
pp. 2192-2205 ◽  
Author(s):  
W. M. Du ◽  
G. Li ◽  
H. Z. Cummins ◽  
M. Fuchs ◽  
J. Toulouse ◽  
...  
Keyword(s):  
Glass Transition ◽  
Light Scattering ◽  
Propylene Carbonate ◽  
Liquid Glass ◽  
Scattering Study

Hydrogen Mobility in the Non-Martensitically Transforming Shape Memory Alloy Ni52Ti48

2012 ◽  
Vol 326-328 ◽  
pp. 731-738
Author(s):  
Giovanni Mazzolai
Keyword(s):  
Diffusion Coefficient ◽  
Glass Transition ◽  
High Temperature ◽  
Lattice Structure ◽  
Mechanical Spectroscopy ◽  
Accurate Analysis ◽  
Niti Sma ◽  
High Temperature Data ◽  
Strain Glass Transition ◽  
B2 Structure

Hydrogen mobility has been studied at high temperature by absorption experiments in the Ni52Ti48 alloy, which does not transform martensitically but rather behaves like a so-called strain glass. The results obtained have been compared with those deduced from an anelastic relaxation occurring in this alloy below the strain-glass transition temperatures. An accurate analysis of the anelastic data has confirmed the conclusion that the relaxation is related to H rather than to the glass transition. Its relaxation time obeyed a Voogel-Fulcher type of temperature dependence. Combining absorption and anelastic results, the H diffusion coefficient in the B2 lattice structure of this alloy could be studied from 1200 K down to 170 K. The agreement between the absorption and mechanical spectroscopy data was satisfactory. The activation energy (0.33 eV) deduced from a Vogel-Fulcher representation of the H diffusion coefficient D was sensibly lower than earlier determinations (0.44-0.50 eV) from Arrhenius plots. The high temperature data of Ni52Ti48 alloy, compared with the ones available in the literature for other NiTi SMA in their B2 structure, show a substantial independence of D on the alloy composition.

Mechanical Properties of an Amorphous or Partially Crystallized Zirconium Based Metallic Glass

2007 ◽  
Vol 539-543 ◽  
pp. 2036-2042 ◽  
Author(s):  
Jean Marc Pelletier ◽  
Sébastien Gravier ◽  
Jean Jacques Blandin
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Elastic Modulus ◽  
Metallic Glass ◽  
Amorphous Material ◽  
Compression Tests ◽  
Mechanical Spectroscopy ◽  
Transition Range ◽  
Temperature Ranges ◽  
Partial Crystallization

The effect of partial crystallization on the mechanical properties of a Zr based bulk metallic glass (Vitreloy 1) is investigated. Viscoelastic properties are studied by mechanical spectroscopy in large frequency and temperature ranges, both below or above the glass transition temperature (Tg), whereas viscoplastic properties are investigated by compression tests . To study the interaction between crystallization and mechanical properties at high temperature, nanocomposites are produced thanks to appropriate heat treatments. Formation of nanocrystalline particles induces an increase of the storage elastic modulus, especially in the glass transition range, where this modulus is very low in the amorphous material. It also results in a decrease of the loss elastic modulus, corresponding to a decrease of the atomic mobility. Finally, partial crystallization induces very large hardening revealed by the compression tests but the hardening extent depends strongly on the applied strain rate.

scholarly journals Low Frequency Mechanical Spectroscopy Study of Three Pyrrolidinium Based Ionic Liquids

2015 ◽  
Vol 60 (1) ◽  
pp. 385-390 ◽  
Author(s):  
F. Trequattrini ◽  
A. Paolone ◽  
O. Palumbo ◽  
F.M. Vitucci ◽  
M.A. Navarra ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Relaxation Time ◽  
Glass Transition ◽  
Solid Phase ◽  
Cold Crystallization ◽  
Mechanical Spectroscopy ◽  
Exponential Factor ◽  
Potential Wells ◽  
Thermally Activated ◽  
Crystallization From The Melt

Abstract In this work we present our recent results on three ionic liquids (ILs), which share bis(trifluoromethanesulfonyl)imide (TFSI) as anion and have different pyrrolidinium based cations. By means of a combination of mechanical spectroscopy and thermal analysis, many of the physical processes occurring during cooling down from the liquid phase, can be studied. Depending both on the diverse cation and the different thermal history, crystallization from the melt or glass transition, cold-crystallization, solid-solid phase transitions and thermally activated processes are observed. In one of the ILs, which could be easily undercooled, a prominent thermally activated peak could be observed above the glass transition. The temperature dependence of the relaxation time is approximated by a Vogel-Fulcher-Tamman equation, as usual for fragile glass forming liquids, and the apparent activation energy of W = 0.36 eV with a pre-exponential factor of the relaxation time τ0 = 1.7 · 10−13s were derived supposing jumps between asymmetrical potential wells. The kinetics of the crystallization processes have been studied in the framework of the Johnson-Mehl-Avrami-Kolmogorov theory and the Avrami parameters have been derived for both the crystallization from the melt and for the cold crystallization observed on heating.

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