The non-Newtonian behaviour of dilute solutions of polymers. II. The non-Newtonian viscosity of polystyrene solutions in relation to the thermodynamic quality of the solvent

1968 ◽  
Vol 33 (7) ◽  
pp. 2130-2141 ◽  
Author(s):  
O. Quadrat ◽  
M. Bohdanecký
Keyword(s):  
Dilute Solutions ◽  
Newtonian Viscosity ◽  
Thermodynamic Quality

Non-Newtonian viscosity and excluded volume effect of dilute solutions of flexible high polymers

1971 ◽  
Vol 75 (8) ◽  
pp. 1141-1149 ◽  
Author(s):  
Yoshihiko Sugiura ◽  
Noriko Yamaguchi ◽  
Koji Okano ◽  
Eiichi Wada
Keyword(s):  
Volume Effect ◽  
Excluded Volume ◽  
Dilute Solutions ◽  
Newtonian Viscosity ◽  
Excluded Volume Effect ◽  
High Polymers

scholarly journals Study of the formation of structures in solutions of chitosan – polyvinyl alcohol polymer blends

2021 ◽  
Vol 23 (2) ◽  
pp. 188-195
Author(s):  
Rinat M. Akhmetkhanov ◽  
Valentina V. Chernova ◽  
Angela S. Shurshina ◽  
Mariya Yu. Lazdina ◽  
Elena I. Kulish
Keyword(s):  
Polyvinyl Alcohol ◽  
Polymer Blends ◽  
Intrinsic Viscosity ◽  
Solvent Interaction ◽  
Polymer Aggregates ◽  
Macromolecular Coil ◽  
Aggregation Processes ◽  
Huggins Constant ◽  
Thermodynamic Quality

The aim of this work was the investigation of the formation of structures in solutions of individual polymers, as well as their blends with each other in buffer solvents with different values of pH. In this study we used a sample of chitosan (degree of deacetylation ~ 84 %, M = 130,000), which is a polycation when dissolved, and polyvinyl alcohol (r = 1.25 g/cm3, M = 5000). Buffer systems based on acetic acid and sodium acetate with pH = 3.8, 4.25, and 4.75 were used as solvents. Viscosimetry was used to determine the intrinsic viscosity, the degree of structuring, and the Huggins constant. The Kriegbaum method was used to determine the nature of the aggregates formed by the blend of the studied polymers. In the course of the research, it was shown that an increase in the pH of the acetate buffer used as a solvent was accompanied by a compression of the macromolecular coil (a decrease in intrinsic viscosity values), a deterioration in the quality of thesolvent (an increase in Huggins constant values), and an increase in the degree of polymer aggregation in a solution for chitosan polyelectrolyte. At the same time for a solution of polyvinyl alcohol the pH of the buffer practically did not affect the nature of the polymer-solvent interaction. It has been proved that polymer blends are characterized by an increase in aggregation processes and a decrease in the thermodynamic quality of the solvent in comparison with solutions of individual polymers. The size of the “combined” macromolecular coil, characterized by the intrinsic viscosity value for the polymer blend, which can be both above (buffer solvent with pH = 3.80) and below (buffer solvent with pH = 4.25 and 4.75) additivevalues, changed depending on the type of formed polymer-polymer aggregates (homo- or hetero-). It was established that the type of aggregates (homo- or hetero-) formed in solutions of polymer blends was determined not only by the thermodynamic quality of the used solvents, but also by the concentration of the polymers in the initial solutions

scholarly journals The influence of arm composition on the self-assembly of low-functionality telechelic star polymers in dilute solutions

2020 ◽  
Author(s):  
Esmaeel Moghimi ◽  
Iurii Chubak ◽  
Dimitra Founta ◽  
Konstantinos Ntetsikas ◽  
George Polymeropoulos ◽  
...  
Keyword(s):  
Self Assembly ◽  
Dynamic Properties ◽  
Star Polymers ◽  
Coarse Grained ◽  
Dilute Solutions ◽  
Solvent Quality ◽  
Physical Experiments ◽  
Coarse Grained Simulations ◽  
Two Populations

Abstract We combine synthesis, physical experiments, and computer simulations to investigate self-assembly patterns of low-functionality telechelic star polymers (TSPs) in dilute solutions. In particular, in this work, we focus on the effect of the arm composition and length on the static and dynamic properties of TSPs, whose terminal blocks are subject to worsening solvent quality upon reducing the temperature. We find two populations, single stars and clusters, that emerge upon worsening the solvent quality of the outer block. For both types of populations, their spatial extent decreases with temperature, with the specific details (such as temperature at which the minimal size is reached) depending on the coupling between inter- and intra-molecular associations as well as their strength. The experimental results are in very good qualitative agreement with coarse-grained simulations, which offer insights into the mechanism of thermoresponsive behavior of this class of materials.

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