Molecular Weight Dependence of Relaxation Time Spectra for the Entanglement and Flow Behavior of Monodisperse Linear Flexible Polymers

Jackson, J. K.; Rosa, Michael E. De; Winter, H. Henning

doi:10.1021/ma00087a010

Cited by 79 publications

(72 citation statements)

References 4 publications

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“…In the entangled regime the longest relaxation time (defined as inversely proportional to the low-frequency maximum omax) scales as N over the experimentally relevant range of N compared with the experimental N3'4 behaviour found for stress relaxation. However, the shape of the loss modulus is in excellent accord with recent stress relaxation experiments (Baumgaertel, DeRosa, Mathado, Masse andWinter 1992, Jackson, DeRosa andWinter 1994) in the following sense. (i) The frequency minimum (oh,,) and corresponding loss modulus decrease weakly with N. (ii) The intermediate behaviour (omax < o < ofin) is a power law o-' with an apparent exponent that increases with N and is roughly 0.2 for N = 1OO00.…”

Section: Numerical Resultssupporting

confidence: 88%

Diffusion and relaxation of chain polymer liquids

Schweizer

Szamel

1995

Philosophical Magazine B

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Section: Numerical Resultssupporting

confidence: 88%

Diffusion and relaxation of chain polymer liquids

Schweizer

Szamel

1995

Philosophical Magazine B

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“…18,19 This slope also corresponds approximately to the high-frequency exponent of the BSW spectrum. 20 The value determined for the microgel, d log(G′′(ω))/d log(ω) ) 0.68, is identical to the value reported for linear PS. 21 It is smaller (i.e., sharper transition, larger steepness index) than that of other polymers.…”

Section: Resultssupporting

confidence: 70%

Mechanical Behavior of Polystyrene Microgels

Roland¹,

Santangelo²,

Antonietti³

et al. 1999

Macromolecules

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Polystyrene microgels are nanometer-sized particles produced by polymerization and crosslinking in microemulsion. As a result of their internal network structure, microgels have negligible intermolecular entanglement interactions. This can have a profound effect on their rheology; it also leads to glassy fracture resembling the behavior of low molecular weight, linear polystyrene. At higher frequencies, the mechanical response of microgels is quite similar to that of linear polystyrene. Breakdown of time-temperature superpositioning occurs in the softening zone of the viscoelastic spectrum. In the glass transition region, the segmental relaxation function is broadened and exhibits an enhanced dependence on temperature. The latter two effects, due to the cross-linking of the microgels, are also seen in conventional, macroscopic networks.

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“…the melt viscosity is linearly related to the longest relaxation time, the prefactor being a function of slopes in the intermediate time-domain. 13 An internal consistency for the plateau modulus is obtained from the slope of latter equation if η 0 is plotted vs τ max.…”

Section: Their Shear Relaxation Modulus G(t) Can Be Conveniently Exprmentioning

confidence: 99%

Rheological Properties of 1,4-Polyisoprene over a Large Molecular Weight Range

et al. 2004

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The dynamic viscoelastic properties of anionically polymerized model 1,4-polyisoprene (PI) with 6-8% 3,4 microstructure and in the range of molecular weights between 1.5 × 10 3 and 3.2 × 10 6 g/mol were reanalyzed using linear rheology. Viscosities obtained in the zero shear-rate limit, η0, up to sufficiently high molecular weight PI samples indicated a clear transition to the pure reptation regime. All characteristic molecular weights, dividing the [η 0,M]-interval in three different regimes could be obtained in high accuracy and a new "triangle" is proposed. The experimental data were analyzed in terms of the empirical Winter-relaxation BSW-model description for both dynamic moduli. The BSW parameters are determined and interpreted in terms of the packing model where possible. Limitations of the packing model are detected and discussed. Additionally, the parameters of the assumed distribution of relaxation times are compared to predictions of microscopic dynamic theories and useful correlations made. The publication deals, in part, with a misconception in the literature for estimates of the constraint release contribution. The monomeric friction coefficient 0, determined in this study for the first time rheologically for anionic PI itself agrees with the natural rubber analogue.

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Molecular Weight Dependence of Relaxation Time Spectra for the Entanglement and Flow Behavior of Monodisperse Linear Flexible Polymers

Cited by 79 publications

References 4 publications

Diffusion and relaxation of chain polymer liquids

Diffusion and relaxation of chain polymer liquids

Mechanical Behavior of Polystyrene Microgels

Rheological Properties of 1,4-Polyisoprene over a Large Molecular Weight Range

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