Thermal analysis of complex relaxation processes in poly(desaminotyrosyl-tyrosine arylates)

Commercially available shape memory polymer (SMP) Estane (designation: ETE75DT3 NAT022) is investigated by means of dynamic mechanical thermal analysis (DMTA) technique in torsion mode using the Modular Compact Rheometer MCR-301 (Anton Paar GmbH). Amplitude sweep tests have been run below and above the glass transition temperature to establish the linear viscoelastic range (LVR) in glassy and rubbery phase of this SMP for the correct physical interpretation of DMTA data. Temperature sweep tests were performed at various frequencies to study the influence of this parameter on values of the storage and loss moduli and the storage and loss compliances as well as the viscosities. These tests have been carried out in heating mode with different rates and at different strain amplitudes. The short- and long-term behavior of SMP Estane have been studied by frequency sweep tests performed at different temperatures and data have been transformed into time-domain properties by applying time-temperature superposition principles. All these DMTA data provide the experimental basis for the study of relaxation processes, property-structure relationships, and the shape memory effect in this little-known SMP.

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Dielectric dispersion, relaxation processes and interaction investigation by time domain reflectometry, thermal analysis and spectral implications on aromatic amino acid in aqueous solution

Journal of Molecular Liquids ◽

10.1016/j.molliq.2021.115470 ◽

2021 ◽

Vol 329 ◽

pp. 115470

Author(s):

K. Vinoth ◽

V. Saravanakannan ◽

P. Senthil Kumar ◽

M. Maria Sylvester ◽

D.J.S. Anand Karunakaran ◽

...

Keyword(s):

Thermal Analysis ◽

Aqueous Solution ◽

Amino Acid ◽

Time Domain ◽

Aromatic Amino Acid ◽

Time Domain Reflectometry ◽

Dielectric Dispersion ◽

Relaxation Processes

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Thermal Analysis of Relaxation Processes of Supersaturated Vacancies in B2-Type Aluminides

MRS Proceedings ◽

10.1557/proc-842-s5.15 ◽

2004 ◽

Vol 842 ◽

Author(s):

Ryusuke Nakamura ◽

Kyosuke Yoshimi ◽

Akira Yamauchi ◽

Shuji Hanada

Keyword(s):

Thermal Analysis ◽

Differential Scanning Calorimetry ◽

Stoichiometric Composition ◽

Recovery Process ◽

Exothermic Peak ◽

Relaxation Behavior ◽

The Other ◽

Relaxation Processes ◽

Scanning Calorimetry ◽

Rapidly Solidified

ABSTRACTRelaxation behavior of supersaturated vacancies in water-quenched and rapidly solidified B2 type CoAl and NiAl with the stoichiometric composition was studied by differential scanning calorimetry (DSC). In both CoAl and NiAl quenched from 1773 K, a single exothermic peak due mainly to the recovery of supersaturated vacancies appeared near 950 K. On the other hand, the exothermic peak was also observed in as-spun rapidly solidified CoAl and NiAl ribbons, and the temperature range of the peak was much broader than that of quenched-in bulks, suggesting that the peak in the rapidly solidified ribbons results from not only a single recovery process of vacancies but also those of some other lattice defects. TEM observation showed that a large amount of dislocations were introduced in the NiAl ribbon and that comparatively many voids as well as an amount of dislocations were introduced in the CoAl ribbon.

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On the effect of the flexibility parameter on thermodynamic properties of acrylonitrile and methylvinylpyridine copolymers

Herald of the Bauman Moscow State Technical University Series Natural Sciences ◽

10.18698/1812-3368-2020-1-71-79 ◽

2020 ◽

pp. 71-79

Author(s):

O.I. Romanko ◽

E.A. Eliseeva

Keyword(s):

Thermal Analysis ◽

Copolymer Composition ◽

Relaxation Processes ◽

Segmental Mobility ◽

Vitrification Temperature ◽

Filter Materials ◽

Temperature Ranges ◽

Effects Of Temperature ◽

Flexibility Parameters ◽

Manufacturing Parameters

We used thermal analysis to investigate the effects of temperature (20--300 °C) on the behaviour of acrylonitrile and methylvinylpyridine copolymers and determine the temperature ranges in which segmental mobility develops in them, as well as their glass transition temperatures. Data obtained via differential thermal analysis allowed us to compute activation energies for vitrification processes in copolymers of the series specified and to plot vitrification temperature as a function of copolymer composition. We used the method of increments to compute flexibility parameters for acrylonitrile and 2-methyl-5-vinylpyridine and analyse the effects of flexibility parameters on the manifestation of relaxation processes. The data obtained may be used to amend manufacturing parameters when developing chemisorptive filter materials based on the specified copolymer series.

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