Polymer swelling, 13: Correlation of flory–huggins interaction parameter, χ, with molecular structure in polystyrene–liquid systems

1992 ◽  
Vol 45 (4) ◽  
pp. 619-631 ◽  
Author(s):  
L. A. Errede
Keyword(s):  
Molecular Structure ◽  
Interaction Parameter ◽  
Polymer Swelling ◽  
Liquid Systems ◽  
Interaction Parameter Χ

Studies in the Thermodynamics of Polymer-Liquid Systems. I. Natural Rubber and Polar Liquids

1965 ◽  
Vol 38 (2) ◽  
pp. 314-324
Author(s):  
C. Booth ◽  
G. Gee ◽  
G. Holden ◽  
G. R. Williamson
Keyword(s):  
Natural Rubber ◽  
Interaction Parameter ◽  
Thermodynamic Data ◽  
The Other ◽  
Vapor Pressures ◽  
Polar Liquids ◽  
Polymer Liquid ◽  
Liquid Systems ◽  
Conventional Study ◽  
Interaction Parameter Χ

Abstract There is a great lack of reliable thermodynamic data on concentrated polymer solutions. This group of papers contributes further measurements, especially on systems consisting of a polar liquid and nonpolar polymer, and presents a review of the current situation. This first part records observations on the swelling of natural rubber in several polar liquids, using two different techniques. One of these is the conventional study of vapor pressures; the other is a novel procedure involving measurements of swelling and tension in stretched crosslinked samples. The results are compared with the Flory-Huggins equation, and show that as swelling proceeds and approaches saturation, there is a marked fall in the interaction parameter χ`. At the same time the entropy of dilution falls progressively further below the curves predicted by current theories.

scholarly journals Accounting for Cooperativity in the Thermotropic Volume Phase Transition of Smart Microgels

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 42
Author(s):  
Simon Friesen ◽  
Yvonne Hannappel ◽  
Sergej Kakorin ◽  
Thomas Hellweg
Keyword(s):  
Phase Transition ◽  
Interaction Parameter ◽  
Quantitative Description ◽  
Water Molecules ◽  
Volume Phase Transition ◽  
Network Chain ◽  
Solvent Interaction ◽  
Volume Phase ◽  
The Cross ◽  
Interaction Parameter Χ

A full quantitative description of the swelling of smart microgels is still problematic in many cases. The original approach of Flory and Huggins for the monomer–solvent interaction parameter χ cannot be applied to some microgels. The reason for this obviously is that the cross-linking enhances the cooperativity of the volume phase transitions, since all meshes of the network are mechanically coupled. This was ignored in previous approaches, arguing with distinct transition temperatures for different meshes to describe the continuous character of the transition of microgels. Here, we adjust the swelling curves of a series of smart microgels using the Flory–Rehner description, where the polymer–solvent interaction parameter χ is modeled by a Hill-like equation for a cooperative thermotropic transition. This leads to a very good description of all measured microgel swelling curves and yields the physically meaningful Hill parameter ν. A linear decrease of ν is found with increasing concentration of the cross-linker N,N′-methylenebisacrylamide in the microgel particles p(NIPAM), p(NNPAM), and p(NIPMAM). The linearity suggests that the Hill parameter ν corresponds to the number of water molecules per network chain that cooperatively leave the chain at the volume phase transition. Driven by entropy, ν water molecules of the solvate become cooperatively “free” and leave the polymer network.

Determination of the interaction parameter χ in the Flory-Rehner equation for coal swelling processes

2011 ◽  
Vol 45 (6) ◽  
pp. 430-433 ◽  
Author(s):  
R. G. Makitra ◽  
G. G. Midyana ◽  
E. Ya. Pal’chikova
Keyword(s):  
Interaction Parameter ◽  
Coal Swelling ◽  
Interaction Parameter Χ
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