On the molecular weight determination by vapour pressure osmometry, 1. Consideration of the calibration function

Marx‐Figini, M.; Figini, R. V.

doi:10.1002/macp.1980.021811118

Cited by 17 publications

(10 citation statements)

References 6 publications

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“…24 The calibration constants K and R were determined with benzene and PS standards of 440 e Mn e 9600 with an accuracy of about (5%. The 1,2/1,4 composition of the d-polybutadienes was determined by 13 C NMR spectroscopy with a Bruker 300 MHz spectrometer.…”

Section: Methodsmentioning

confidence: 99%

Phase Behavior and Flory−Huggins Interaction Parameter of Binary Polybutadiene Copolymer Mixtures with Different Vinyl Content and Molar Volume

Schwahn

Willner

2001

Macromolecules

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Binary blends of statistical polybutadiene copolymers of different vinyl content were explored by small-angle neutron scattering. These samples represent the simplest class of statistical copolymer mixtures. In spite of this simplicity, strong changes of phase behavior were observed with varying vinyl content, molar volume, and deuteration; the temperatures of phase separation are found between -230°C and more than 200°C and phase separation can even reverse from an enthalpically driven one at low temperatures (UCST) to an entropically driven one at high temperatures (LCST). The experimentally determined entropic and enthalpic terms of the Flory-Huggins parameter are in excellent agreement with lattice cluster theory calculations by Dudowicz and Freed.

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Section: Methodsmentioning

confidence: 99%

Phase Behavior and Flory−Huggins Interaction Parameter of Binary Polybutadiene Copolymer Mixtures with Different Vinyl Content and Molar Volume

Schwahn

Willner

2001

Macromolecules

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“…The solvent was benzene, which was distilled from CaH 2 . The M n values were obtained using a calibration function of the type (Δ V / c ) c → 0 = K , where Δ V is the change in voltage of the thermistors and c is the concentration …”

Section: Methodsmentioning

confidence: 99%

Structural Investigation of Micelles Formed by an Amphiphilic PEP−PEO Block Copolymer in Water

et al. 1997

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Micelles of a poly(ethylene-co-propylene)-block-Poly(ethylene oxide) (PEP−PEO) copolymer in water were investigated by small angle neutron scattering (SANS), dynamic light scattering (DLS), and viscometry. The block copolymer was built of a partially deuterated PEP block and a hydrogeneous PEO block with an overall molecular weight of 11.1 × 103. The SANS measurements were performed at four contrasts in order to get detailed structural information about the micellar aggregates. The different scattering curves could be described very well by a spherical core−shell model with constant density in both parts. The sharp edges of the polymer density distribution were smeared by multiplication with a Gaussian in Q-space. The model yielded a core radius of R C = 176 Å and an overall micellar radius of R M = 294 Å. The smearing ranges were 11 and 32 Å, respectively. The fit further yielded an aggregation number of P = 2430. DLS measurements reveal a narrow monomodal distribution of relaxation frequencies, indicating the existence of only one aggregated species. The obtained hydrodynamic radius, R H = 339 Å, as well as the radius determined by viscosity measurements, R V = 324 Å, are consistent with the result of the model fitting. The unusually large aggregation number could be explained by the large interfacial tension between water and PEP in terms of simple thermodynamic models.

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“…The Mn values were obtained using a calibration function of the type (∆V/c)cf0 ) KM n R , where ∆V is the change of the thermistors in voltage and c is the concentration. 22 The calibration constants K and R were determined with benzene and PS standards of 440 e Mn e 9600 with an accuracy of about (5%. The 1,2/1,4 composition of the d-polybutadienes was determined by 13 C NMR spectroscopy with a Bruker 300-MHz spectrometer.…”

Section: Methodsmentioning

confidence: 99%

Blends of Polybutadiene with Different Vinyl Contents and Polystyrene Studied with Small-Angle Neutron Scattering in Varying Temperature and Pressure Fields

2001

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Blends of polybutadiene with three different vinyl contents and polystyrene were studied by small-angle neutron scattering as a function of temperature and pressure. The data were analyzed with a crossover function combining the universality classes of the 3D-Ising and the mean field behavior and thus yield the spinodal temperature T S, the Ginzburg number Gi, and the critical amplitude CMF. From these parameters the mean field Flory-Huggins interaction parameter is calculated in terms of entropic and enthalpic contributions. The application of the theory of random copolymers delivers large enthalpic and entropic contributions of the intramolecular interaction between the 1,2-and 1,4-butadiene units. These numbers could not be confirmed from measurements of the corresponding intermolecular interaction contributions in an h-PB(1,2)/d-PB(1,4) blend, which thus leads to speculations about the equivalence of inter-and intramolecular interactions in random copolymers. The Ginzburg number proved to be specific to the vinyl content and thus deviated from the universal behavior Gi ∝ V -1 predicted by deGennes. By our pressure experiments we find that the Clausius-Clapeyron equation suggests the phase boundary to be influenced by the Flory-Huggins parameter and the Ginzburg number.

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On the molecular weight determination by vapour pressure osmometry, 1. Consideration of the calibration function

Cited by 17 publications

References 6 publications

Phase Behavior and Flory−Huggins Interaction Parameter of Binary Polybutadiene Copolymer Mixtures with Different Vinyl Content and Molar Volume

Phase Behavior and Flory−Huggins Interaction Parameter of Binary Polybutadiene Copolymer Mixtures with Different Vinyl Content and Molar Volume

Structural Investigation of Micelles Formed by an Amphiphilic PEP−PEO Block Copolymer in Water

Blends of Polybutadiene with Different Vinyl Contents and Polystyrene Studied with Small-Angle Neutron Scattering in Varying Temperature and Pressure Fields

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