Pressure effects in polymer solution phase equilibriums. II. Systems showing upper and low critical solution temperatures

Zeman, Leos J.; Patterson, D.

doi:10.1021/j100652a022

Cited by 98 publications

(91 citation statements)

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“…There is reasonable agreement between theory and experiment for the magnitude of this pressure coefficient, although the absolute value of the LCST observed at any p is less than predicted by theory (Ref. 28,29).…”

Section: Nh2supporting

confidence: 54%

Recent trends in classical light scattering from polymer solutions

Huglin¹

1977

Pure and Applied Chemistry

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-Extension of usable wavelengths to the near i.r. by means of laser sources enables the molecular weights and dimensions to be measured for exceptionally large macromolecules and bacteria. Comparisons have been made between experimental and theoretically predicted behaviour of solutions subjected to external constraints such as temperature, applied pressure and hydrodynamic shear. Scission and molecular motion can be analysed via light scattering in polymers subjected to laser or pulse degradation; kinetics of anionic polymerisation may be clarified by estimating the association of the living polymer. Problems associated with compositional heterogeneity in copolytners and terpolymers are discussed as is the anomalous behaviour of block copolymers in which one portion is optically masked. In principle, the compatibility between two polymers in a common solvent can be determined quantitatively, but the techniques demand an exceptionally high level of care and accuracy.

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Section: Nh2supporting

confidence: 54%

Recent trends in classical light scattering from polymer solutions

Huglin¹

1977

Pure and Applied Chemistry

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“…According to a recent review 8 and ú900 at 20 MPa. 9 Zeman and Patterson 9 suggest that acetone may even be able ments with DMCH, however, indicated these solutions to already be in the Q configuration, albeit to dissolve infinite MW at high pressure (the system thus having made the transition from ''poor'' with a small Q gap. We, therefore, chose to explore ''poor-Q'' continuity with studies on PS/EF.…”

Section: Introductionmentioning

confidence: 99%

Continuity of solvent quality in polymer solutions. Poor-solvent to Θ-solvent continuity in some polystyrene solutions

Imre

Hook

1997

J. Polym. Sci. B Polym. Phys.

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“…Figure 6 Number average molecular weight vs. conversion for batch polymerization of methacrylic acid at 80°C. For the FRRPP system, the reactor contained 12 g methacrylic acid, 120 g water, 0.06 g V-50, 17 g Span 20 surfactant, and 196 g mixed xylenes.…”

Section: Conversionmentioning

confidence: 99%

Studies of the polymerization of methacrylic acid via free-radical retrograde precipitation polymerization process

Aggarwal

Saxena

Wang

et al. 1996

J. Appl. Polym. Sci.

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SYNOPSISIn this paper, we present some new results of our work in a novel polymerization process (called the free-radical retrograde precipitation polymerization, or FRRPP, process) that occurs at temperatures above the lower critical solution temperature. Our polymerization experiments basically involve the methacrylic acid-poly(methacry1ic acid)-water system. Experimental results indicate a gradual increase in conversion with time after what seemingly is the onset of phase separation. In an equivalent solution polymerization system, conversion of methacrylic acid reaches almost 100% at a much shorter time than in the FRRPP system. Molecular weights of poly(methacry1ic acid) at different times for the FRRPP system are not dramatically different from those obtained in the solution system. However, the FRRPP system yields a relatively narrow molecular weight distribution at a wide range of conversion compared to that obtained in the equivalent solution system. The unique characteristics of the FRRPP process is shown in the asymptotic time behavior of the free-radical concentration compared to the decay behavior in other polymerization systems. 0 1996 John Wiley & Sons, Inc. I NTRO DUCT1 0 NWithin the past several years, we have been studying the physico-chemical and product material aspects of a free-radical precipitation polymerization reaction systems wherein phase separation occurs above the lower critical solution temperature (LCST).l In contrast with conventional precipitation polymerization (CPP) p r o c e s~~-~ that involves phase separation below the upper critical solution temperature (UCST). We call this new process a free-radical retrograde precipitation polymerization (FRRPP) process (see Fig. 1). The added complication of retrograde precipitation could be offset by tighter control of reactor operating conditions and polymer molecular properties. Also, the relatively low operating pressures typically needed are not of great economic disadvantage inasmuch as commercial implemen-

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Pressure effects in polymer solution phase equilibriums. II. Systems showing upper and low critical solution temperatures

Cited by 98 publications

References 0 publications

Recent trends in classical light scattering from polymer solutions

Recent trends in classical light scattering from polymer solutions

Continuity of solvent quality in polymer solutions. Poor-solvent to Θ-solvent continuity in some polystyrene solutions

Studies of the polymerization of methacrylic acid via free-radical retrograde precipitation polymerization process

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