scholarly journals Effect of precise linker length, bond density, and broad temperature window on the rheological properties of ethylene vitrimers

Soft Matter ◽  
2021 ◽  
Author(s):  
Bhaskar Soman ◽  
Christopher M. Evans
Keyword(s):  
Relaxation Time ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Rheological Properties ◽  
Dynamic Networks ◽  
Arrhenius Behavior ◽  
Linker Length ◽  
Bond Density ◽  
Temperature Window

Dynamic networks with precise spacers between boronic ester bonds were investigated over a broad temperature window. Arrhenius behavior breaks down and an increase in relaxation time is observed when approach the glass transition temperature.

scholarly journals Oбобщенный кинетический критерий перехода жидкость--стекло

2020 ◽  
Vol 62 (10) ◽  
pp. 1706
Author(s):  
Д.С. Сандитов ◽  
В.В. Мантатов ◽  
С.Ш. Сангадиев
Keyword(s):  
Relaxation Time ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Cooling Rate ◽  
Glassy State ◽  
Fluctuation Volume ◽  
Dimensionless Constant ◽  
Transition Criterion

Using the model of delocalized atoms, a substantiation and generalization of the Schmelzer glass transition criterion is proposed. In contrast to the Bartenev and Volkenstein - Ptitsyn approaches, in the generalized kinetic glass transition criterion, along with the relaxation time and the cooling rate of the melt, the glass transition temperature and an almost universal dimensionless constant appear, which is determined by the fraction of the fluctuation volume frozen at the glass transition temperature. The idea is developed that the liquid goes into a glassy state when its cooling rate q reaches a certain fraction of C_g of the characteristic cooling rate q_g=(T_g/taug), which is closely related to the relaxation time of the structure tau_g at the glass transition temperature T_g.

Effects of counterion size and backbone rigidity on the dynamics of ionic polymer melts and glasses

2017 ◽  
Vol 19 (40) ◽  
pp. 27442-27451 ◽  
Author(s):  
Yao Fu ◽  
Vera Bocharova ◽  
Mengze Ma ◽  
Alexei P. Sokolov ◽  
Bobby G. Sumpter ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polymer Melts ◽  
Static Dielectric Constant ◽  
Segmental Dynamics ◽  
Ionic Polymer ◽  
Segmental Relaxation

Backbone rigidity, counterion size and the static dielectric constant affect the glass transition temperature, segmental relaxation time and decoupling between counterion and segmental dynamics in significant manners.

Luminescence différée d'une solution organique vitreuse photoactivée et transition vitreuse

1977 ◽  
Vol 55 (13) ◽  
pp. 2517-2522 ◽  
Author(s):  
D. Ceccaldi
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Kinetic Theory ◽  
Rise Time ◽  
Time Dependent ◽  
Glassy Matrix ◽  
Temperature Dependent

A general kinetic theory is used to explain the shapes of photoionized sample luminescence curves perturbed by thermal jumps (Δ ∼ 1 K, rise time ∼ 1 s). The samples studied are photoactivated organic vitreous solutions of TMPD/MCH 10−3 M and TMPD/3-MP 10−3 M. The experiments are performed within a temperature range (63–91 K) which includes the glass transition temperature Tg. It is shown that there is a slow diffusion of the trapped electrons towards the cation and competition between thermal detrapping and tunneling. The tunneling/thermal detrapping ratio Y is not time dependent during an isothermal luminescence and is only slowly temperature dependent if T ≤ Ty. Ty is very close to Tg. For T > Ty, Y decreases rapidly with T. The activation energy for thermal detrapping shows a maximum when the temperature reaches [Formula: see text] The glass transition temperature Tg may therefore be defined empirically as:[Formula: see text]Finally we obtain a glassy matrix relaxation time, τ, which decreases with T.

Glass Transition Temperature and Value of the Relaxation Time at Tg in Vitreous Polymers

2007 ◽  
Vol 258 (1) ◽  
pp. 152-161 ◽  
Author(s):  
Jean Marc Saiter ◽  
Jean Grenet ◽  
Eric Dargent ◽  
Allisson Saiter ◽  
Laurent Delbreilh
Keyword(s):  
Relaxation Time ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature

Relaxation Time at Glass Transition Temperature Measured by Simplex Thermo Stimulated Depolarisation Current

2014 ◽  
Vol 341 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Hadj Bahous ◽  
Manil M. Soufi ◽  
Laurent Meuret ◽  
Mohammed Benzohra
Keyword(s):  
Relaxation Time ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature

Impact of metal cations on the thermal, mechanical, and rheological properties of telechelic sulfonated polyetherimides

2020 ◽  
Vol 11 (2) ◽  
pp. 393-400 ◽  
Author(s):  
Ke Cao ◽  
Joel M. Serrano ◽  
Tianyu Liu ◽  
Benjamin J. Stovall ◽  
Zhen Xu ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Thermal Degradation ◽  
Rheological Properties ◽  
Metal Cation ◽  
Complex Viscosity ◽  
Degradation Temperature ◽  
Cation Size ◽  
Thermal Degradation Temperature

The glass transition temperature, thermal degradation temperature, and complex viscosity of metal sulfonated polyetherimides decrease with an increase in metal cation size.

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