Influence of the Solvent Quality on the Thermodynamic Behavior of Polymethylphenylsiloxane Solutions

2010 ◽  
Vol 49 (24) ◽  
pp. 12740-12746 ◽  
Author(s):  
Cristina-Eliza Brunchi ◽  
Simona Morariu ◽  
Maria Cazacu ◽  
Maria Bercea
1995 ◽  
Vol 5 (9) ◽  
pp. 1269-1275 ◽  
Author(s):  
W. Essafi ◽  
F. Lafuma ◽  
C. E. Williams

1995 ◽  
Vol 60 (11) ◽  
pp. 1905-1924 ◽  
Author(s):  
Hong Phuong-Nguyen ◽  
Geneviève Delmas

Dissolution, crystallization and second dissolution traces of isotactic poly(propylene) have been obtained in a slow temperature ramp (3 K h-1) with the C80 Setaram calorimeter. Traces of phase-change, in presence of solvent, are comparable to traces without solvent. The change of enthalpy on heating or cooling, ∆Htotal, over the 40-170 °C temperature range, is the sum of two contributions, ∆HDSC and ∆Hnetwork. The change ∆HDSC is the usual heat obtained in a fast temperature ramp and ∆Hnetwork is associated with a physical network whose disordering is slow and subject to superheating due to strain. When dissolution is complete, ∆Htotal is equal to ∆H0, the heat of fusion of perfect crystals. The values of ∆Htota for nascent and recrystallized samples are compared. Dissolution is the tool to evaluate the quality of the crystals. The repartition of ∆Htotal, into the two endotherms, reflects the quality of crystals. The crystals grown more rapidly have a higher fraction of network crystals which are stable at high T in the solvents. A complete dissolution, i.e. a high temperature (170 °C or more) is necessary to obtain good crystals. The effect of concentration, polymer molecular weight and solvent quality on crystal growth is analyzed.


Gels ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 20
Author(s):  
Matan Mussel ◽  
Peter J. Basser ◽  
Ferenc Horkay

Incremental changes in ionic composition, solvent quality, and temperature can lead to reversible and abrupt structural changes in many synthetic and biopolymer systems. In the biological milieu, this nonlinear response is believed to play an important functional role in various biological systems, including DNA condensation, cell secretion, water flow in xylem of plants, cell resting potential, and formation of membraneless organelles. While these systems are markedly different from one another, a physicochemical framework that treats them as polyelectrolytes, provides a means to interpret experimental results and make in silico predictions. This article summarizes experimental results made on ion-induced volume phase transition in a polyelectrolyte model gel (sodium polyacrylate) and observations on the above-mentioned biological systems indicating the existence of a steep response.


2003 ◽  
Vol 36 (2) ◽  
pp. 389-398 ◽  
Author(s):  
Phillip A. Schorr ◽  
Thomas C. B. Kwan ◽  
S. Michael Kilbey ◽  
Eric S. G. Shaqfeh ◽  
Matthew Tirrell

1978 ◽  
Vol 9 (4) ◽  
Author(s):  
F. SOMMER ◽  
B. PREDEL ◽  
D. ESCHENWECK ◽  
G. OEHME

2017 ◽  
Vol 26 (12) ◽  
pp. 1743024 ◽  
Author(s):  
Pablo Bueno ◽  
Pablo A. Cano

We argue that, when certain higher-curvature corrections are added to the four-dimensional Einstein–Hilbert action, black holes become stable below certain mass. We show this to be the case for an infinite family of ghost-free theories involving terms of arbitrarily high order in curvature. The thermodynamic behavior of the new black holes is universal for arbitrary values of the couplings, with the only exception of the Schwarzschild solution itself, which is recovered when all the couplings are set to zero. For this class of theories, the issue of non-unitary evolution is inexistent, as black holes never evaporate completely.


2013 ◽  
Vol 32 (1) ◽  
pp. 172-177 ◽  
Author(s):  
Tom Mills ◽  
Adeline Koay ◽  
Ian T. Norton
Keyword(s):  

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