Thermodynamic aspects of polymer compatibility

Koningsveld, R.; Kleintjens, L. A.; Schoffeleers, H. M.

doi:10.1351/pac197439010001

Cited by 161 publications

(67 citation statements)

References 31 publications

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“…In general, w FHS depends on temperature T, pressure p and volume fraction j of the mixture (w FHS ¼ w FHS (p, T, j)). Independently of the functional form of w FHS (p, T, j), there are basic properties common to all binary mixtures with a miscibility gap: Firstly, the critical points are always extrema of the spinodal curve and therefore also of the coexistence curve 4 and secondly, the cloud point curve where the system demixes into two phases and the coexistence curve which indicates the compositions of the two phases are identical. The phase diagram of a binary polymer mixture of mondisperse components is shown schematically in Scheme 1(a).…”

Section: Theorymentioning

confidence: 99%

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

Eckert

Meier

Alig

2002

Phys. Chem. Chem. Phys.

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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 b ¼ 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 ¼ 0.46, y PPG : mass fraction of polypropylene glycol) and a mixture of non-critical composition (y PPG ¼ 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.

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Section: Theorymentioning

confidence: 99%

“…4 A possibility to reduce the enormous calculation expense for a high number of components is the so-called continuous thermodynamics. [10][11][12][13] This means that instead of a discrete distribution of molar masses, a continuous distribution, over which integration can be performed, is assumed.…”

Section: Theorymentioning

confidence: 99%

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

Eckert

Meier

Alig

2002

Phys. Chem. Chem. Phys.

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“…In general, this can be explained by a polydispersity of the compounds. 40,41 In this case, the two-dimensional phase diagram of the system is just a quasi-binary section of the high dimensional phase space spanned by all components with different molar masses. Upon demixing, a fractionation of the polymers occurs for all mixtures except the critical mixture.…”

Section: A Phase Diagrammentioning

confidence: 99%

Composition fluctuations in a non-critical binary polymer blend studied by ultrasonic and light scattering experiments

Eckert

Hoffmann

Meier

et al. 2002

Phys. Chem. Chem. Phys.

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A non-critical mixture of polyethylene glycol (PEG600, M ¼ 600 g mol À1) and polypropylene glycol (PPG1000, M ¼ 1000 g mol À1) was investigated by ultrasonic and light scattering experiments in the one-phase region. The mass fraction of polypropylene glycol in the non-critical mixture was y PPG ¼ 0.365. The explored temperature and frequency range of the ultrasonic experiment was 0.1 T À T P 17.3 K and 0.4 MHz f 30 MHz (T P : phase separation temperature). The frequency dependence of the ultrasonic attenuation of the non-critical mixture shows a relaxation behaviour typical for composition fluctuations. The data can be analysed by the dynamic scaling theory of Bhattacharjee and Ferrell which was formally extended to the non-critical case using the concept of a pseudospinodal temperature. The characteristic time scale of the concentration fluctuations is described by a frequency o D ¼ 2D/x 2 where D is the mutual diffusion coefficient and x is the correlation length. In the frame of the pseudospinodal concept the temperature dependence of the characteristic frequency is expressed by o D ¼ o 0 e zn with e ¼ (T À T PS )/T PS (T PS : pseudospinodal temperature, e: reduced temperature, o 0 : critical amplitude, zn: critical exponent). The temperature dependence of the frequency o D was determined by the ultrasonic spectra. From this data, using mean field exponents, a value of o 0 ¼ 9.4 MHz was estimated which is comparable to that of the critical mixture. The description of the ultrasonic data with mean field exponents is justified by the results of dynamic light scattering.

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“…21 Here we extend the analysis somewhat further, assuming g 1 and to be independent of T , and the temperature g 2 dependence of to be given by the usual form :…”

Section: Practically-binary Blendsmentioning

confidence: 99%

Liquid-liquid phase separation in multicomponent polymer systems. XXVII. Determination of the pair-interaction function for polymer blends

Koningsveld

MacKnight

1997

Polym. Int.

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Thermodynamic aspects of polymer compatibility

Abstract: Abstract

Cited by 161 publications

References 31 publications

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

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

Composition fluctuations in a non-critical binary polymer blend studied by ultrasonic and light scattering experiments

Liquid-liquid phase separation in multicomponent polymer systems. XXVII. Determination of the pair-interaction function for polymer blends

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