Phase behaviour of mixtures of polyethylene glycol and polypropylene glycol : influence of hydrogen bond clusters on the phase diagram

Eckert, S.; Meier, G.; Alig, I.

doi:10.1039/b203060h

Journal Article

Phase behaviour of mixtures of polyethylene glycol and polypropylene glycol : influence of hydrogen bond clusters on the phase diagram

Eckert, S.FZJ* ; Meier, G. ; Alig, I.

2002
RSC Publ. Cambridge

Physical Chemistry Chemical Physics 4, 3743 - 3749 (2002) [10.1039/b203060h]

This record in other databases:

Please use a persistent id in citations: http://hdl.handle.net/2128/1590 http://hdl.handle.net/2128/2865 doi:10.1039/b203060h

Abstract: The phase behaviour of a binary polymer blend of polyethylene glycol ( PEG600) and polypropylene glycol (PPG1000) of low polydispersity was investigated. The coexistence curves of five different compositions, including the critical composition, were measured by differential refractometry. From the coexistence curves, the critical exponents of the order parameter could be determined. The order parameter of the coexistence curve of the critical composition was beta = 0.357, near to the Ising value. The measured coexistence curves for different compositions were different to each other and to the cloud point curve measured by small angle light scattering. These differences are explained by clusters built of intermolecular hydrogen bonds which lead to a broad effective molar mass distribution of the mixture. Two of the investigated mixtures, the mixture of critical composition (y(PPG) = 0.46, y(PPG) : mass fraction of polypropylene glycol) and a mixture of non-critical composition (y(PPG) = 0.365) were also measured 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. The light scattering measurements showed, additionally to the composition fluctuations due to the phase transition of demixing, a contribution of larger objects, which could be attributed to hydrogen bonded clusters. The size of these clusters was estimated to be 250 nm to 550 nm.

Keyword(s): J

Classification:

Note: Record converted from VDB: 12.11.2012

Contributing Institute(s):