Phase behaviour of mixtures of polyethylene glycol and polypropylene glycol: Influence of hydrogen bond clusters on critical composition fluctuations

Abstract

The critical behaviour of a binary polymer blend of polyethylene glycol 600 (PEG600) and polypropylene glycol 1000 (PPG1000) was investigated by static and dynamic light scattering. The measurements were carried out in the homogeneous one-phase region (above the critical temperature T c) and in the two-phase region in both coexisting phases. Additionally to the critical composition (y PPG ¼ 0.46, y PPG : mass fraction of PPG), a mixture of non-critical composition (y PPG ¼ 0.365) was investigated in the one-and two-phase region. From the light scattering measurements, the critical exponents and the amplitudes of the correlation length x and the mutual diffusion coefficient D were determined. For the critical mixture the results for the critical exponents and amplitudes of x in the one-and two-phase regions are in accordance with the predictions of the 3d-Ising model. The measurements of D in the two-phase region in a wider temperature range gave an indication for a crossover from Ising to mean field behaviour. Since the low molar mass of the PEG and PEG oligomers would lead to Ising behaviour in the composition and temperature range studied, this crossover has to be attributed to an increase of the effective molar mass caused by clusters built by intermolecular hydrogen bonds. The assumption of these clusters is supported by static light scattering and the phase diagram. The data of the non-critical mixture could be described in the frame of the pseudospinodal concept. The results for the non-critical mixture support the interpretation of the data of the critical mixture.

Melt‐rheological behavior of high‐solid cement‐in‐polymer dispersions

“…In such a series, the order reads dimethyl ether < monomethyl ether < diol. A similar trend was observed for solutions of poly(ethylene oxide)s in ethylene glycol or ethylene glycol ethers and was explained by the formation of intermolecular hydrogen bonds, which give rise to so called “apparent longer chains.”21, 22 Hydrogen bonding also seems to occur in the pure polymer melts in the case of the diol or the monomethyl ether as, e.g., for the 1000 g mol −1 series, the dynamic viscosity of the diol is 54% and that of the monomethyl ether 30% higher than that of the dimethyl ether. However, due to hydrogen bonds being considerably weaker than covalent bonds, the dynamic viscosity of the 1000 g mol −1 monomethyl ether is lower than the one of the 2000 g mol −1 dimethyl ether.…”

“…However, poly(ethylene oxide)s are known to show a different behavior, as the slope in the double‐logarithmic plot continuously increases 23. This was explained by a continuously increasing content of intermolecular chain interactions, possibly due to hydrogen bonding 21, 22…”

Highly Porous, Biocompatible Tough Hydrogels, Processable via Gel Fiber Spinning and 3D Gel Printing

“…[17,18] The important aspect of the phase separation of PPG and PEG linear chains is their slow kinetics even when the polymer chains are short and supposedly dynamic. [17,18] The important aspect of the phase separation of PPG and PEG linear chains is their slow kinetics even when the polymer chains are short and supposedly dynamic.…”

“…The phase separation between PPG and PEG linear chains is well-known and has been studied before. [17,18] The important aspect of the phase separation of PPG and PEG linear chains is their slow kinetics even when the polymer chains are short and supposedly dynamic. The slow phase separation in the binary PEG-PPG linear chain system has been attributed to the formation of new hydrogen bonds between polymer chains during the process of phase separation, with light scattering and Fourier transform infrared spectroscopy data supporting this hypothesis.…”

“…The phase separation between PPG and PEG linear chains is well‐known and has been studied before . The important aspect of the phase separation of PPG and PEG linear chains is their slow kinetics even when the polymer chains are short and supposedly dynamic.…”