Hydrodynamic Properties of Polymer Mixtures in Solution

Abstract

The paper investigates the hydrodynamic properties of polyacrylonitrile (PAN) and poly(N-(4-carboxyphenyl)maleimide) (PMI) solutions in dimethylformamide (DMF) in comparison with PMI/PAN/DMF ternary mixtures. The experimental data obtained by viscometry have been discussed by means of two methods: first, the plots obtained with the classical Huggins equation are analyzed, and in parallel, an evaluation of the parameters given by the new Wolf model is presented. The experimental data obtained for binary polymer/solvent and ternary polymer/polymer/solvent mixtures fit well with this last method and allow the calculation of intrinsic viscosities and other hydrodynamic parameters, which provide new information about the competition between different types of interactions for polymer mixtures in solution. The compatibility of the two polymers dissolved in a common solvent is also discussed on the basis of two parameters: Δb and α, reflecting the interactions between the polymer segments and polymer/polymer miscibility, respectively. The sign of these parameters shows that the PMI/PAN blends in DMF are miscible in the range of PAN mass fraction between 0.36 and 0.75.

The Behavior of Poly(dimethylsiloxane-co-diphenylsiloxane)s in Good and Theta Solvents

“…Figure also illustrates very clearly the limitation of the Huggins equation in the data evaluation, especially in the region of very low concentrations, where the reduced viscosity deviates upward from linearity. Such positive deviations from linear behavior in the dependence of η sp / c versus c in the region of very low concentrations have been reported previously for many polymer solutions, ,,, making the extrapolation of the experimental data to zero concentration more difficult.…”

“…A new alternative method for the determination of [η] of polyelectrolytes that was developed very recently is based on the following equation: η rel = c [ η ] w + B c 2 [ η ] w [ η ] • 1 + B c [ η ] w where B represents a system-specific constant and [η] • is the characteristic specific hydrodynamic volume. Equation was successfully verified for different polyelectrolyte solutions − and solutions of neutral polymers , and copolymers, and thus, it can be applied for siloxane copolymers in solution.…”

Rheological investigation of poly(vinyl alcohol)/poly(N-vinyl pyrrolidone) mixtures in aqueous solution and hydrogel state

“…2 The viscoelastic moduli (G', G″) and the phase shift as a function of the oscillation frequency (ω) for the sample with 25 % PVP in the PVA/ PVP mixture, at 37°C 0.011 s and it reaches a maximum for 25 % PVP in the PVA/ PVP mixture when the relaxation time is twice as compared with those of the pure components. This behavior can be due to an increase of polymer-polymer interactions between unlike and like macromolecules [30][31][32][33] and cluster formation in the system. The larger clusters determine a larger relaxation time and the cluster reaches infinite size near the sol-gel transition when it still relaxes, but the relaxation time becomes infinitely large [34].…”

Ionic polymers based on quaternized polysulfones: hydrodynamic properties of polymer mixtures in solution

“…(3) was initially developed for the evaluation of intrinsic viscosity of polyelectrolytes in aqueous solutions in the presence/absence of salts [31,45], it was also successfully applied for polyelectrolytes in aqueous/organic solvent mixtures and for neutral (co)polymers, neutral polymer mixtures, and polyelectrolytes/neutral polymers mixtures [46].…”