Rheology of star polymers in concentrated solutions and melts

Doi, Masao; Kuzuu, Nobu

doi:10.1002/pol.1980.130181205

Cited by 188 publications

(180 citation statements)

References 10 publications

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“…Shanbhag and Larson applied the primitive path analysis (PPA) algorithm [97] to study the primitive path of the BFM. The obtained results confirm the quadratic form for the potential of tube-diameter fluctuation, with a prefactor of 1.5, which has been theoretically predicted by Doi and Kuzuu [98]. However, the BFM is a Monte Carlo simulation and cannot be applied to study the dynamic moduli and the viscosity of polymers.…”

Section: (A) (B)supporting

confidence: 64%

Challenges in Multiscale Modeling of Polymer Dynamics

et al. 2013

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The mechanical and physical properties of polymeric materials originate from the interplay of phenomena at different spatial and temporal scales. As such, it is necessary to adopt multiscale techniques when modeling polymeric materials in order to account for all important mechanisms. Over the past two decades, a number of different multiscale computational techniques have been developed that can be divided into three categories: (i) coarse-graining methods for generic polymers; (ii) systematic coarse-graining methods and (iii) multiple-scale-bridging methods. In this work, we discuss and compare eleven different multiscale computational techniques falling under these categories and assess them critically according to their ability to provide a rigorous link between polymer chemistry and rheological material properties. For each technique, the fundamental ideas and equations are introduced, and the most important results or predictions are shown and discussed. On the one hand, this review provides a comprehensive tutorial on multiscale computational techniques, which will be of interest to readers newly entering this field; on the other, it presents a critical discussion of the future opportunities and key challenges in the multiscale geometric mapping matrix between all-atomistic and coarse-grained models N number of monomers per chain N e entanglement length, which is the number of monomers between two entanglements n v number of polymer chains per unit volume n ij (n 0 (r ij )) entanglement number (at equilibrium) between particle pairs i and j p r , P R configurational probability distributions in all-atomistic and coarse-grained models, respectively R ee end-to-end distance of polymer chain R G radius of gyration of polymer chain s segment index/contour length variable along primitive chain S(q) single chain coherent dynamic scattering function Z number of entanglements per chain, defined as Z = N/N e α exponent in standard Mittag-Leffler function σ

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Section: (A) (B)supporting

confidence: 64%

Challenges in Multiscale Modeling of Polymer Dynamics

et al. 2013

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“…The viscosity of polymers having sufficiently long branches will have a stronger dependence on molecular weight than the power law found for linear chains (eqs 2 and 3). An exponential relationship has been proposed [15][16][17] 37 vertically scaled to superpose on the data for L176.…”

Section: Discussionmentioning

confidence: 99%

“…The general consensus is that stress relaxation and diffusion entail arm retraction, which causes an exponential increase with branch length of both the zero-shear viscosity and the diffusion constant. [10][11][12][13][14][15][16][17][18] This arm retraction is believed 19 to be the cause of two other phenomena associated with branched polymers: more temperature-dependent rheological properties and thermorheological complexity in the terminal zone. [20][21][22][23][24][25][26][27] The transient, compact structure would alter the distribution of rotational states, in turn giving rise to a thermal barrier to terminal relaxation, which is absent for linear polymers.…”

Section: Introductionmentioning

confidence: 99%

Rheology of Star-Branched Polyisobutylene

1999

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The rheology of high molecular weight, six-arm-star polyisobutylenes (PIB) was measured and compared to the behavior of linear PIB. The polymers had equivalent plateau moduli and conformed well in the terminal zone to the time-temperature superposition principle. Moreover, the temperature coefficients of the terminal relaxation times were identical for the star and linear polymers. Since the trans and gauche conformations in PIB have virtually the same energy, this absence of enhanced temperature sensitivity in star PIB, as well as the thermorheological simplicity, is consistent with an interpretation of the rheology of branched polymers based on an arm retraction mechanism.

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“…The early CLF studies of Doi and co-workers 14,47 suggest that relaxation due to contour length fluctuations becomes exponentially less probable as one moves away from the chain ends. However, Milner and McLeish have recently proposed an alternative scaling, 15 which improves predictions for the high frequency asymptote of the dynamic loss modulus and gives good agreement with the experimentally observed 3.4-power dependence of the zero shear viscosity and reptation time scale with the polymer molecular weight.…”

Section: Ccr and Clf Models (A) Contour Length Fluctuations (Clf)mentioning

confidence: 99%

Extensional Rheometry of Entangled Solutions

et al. 2002

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The seminal ideas of de Gennes and Doi and Edwards have provided the theoretical framework for much of the recent effort to model the rheological behavior of entangled polymer melts and solutions. Recent theoretical work has incorporated a number of important additions to the basic Doi-Edwards theory, including an explicit description of chain stretch and additional relaxation mechanisms such as contour length fluctuations (CLF) and convective constraint release (CCR). However, very little quantitative data has been published on the rheological behavior of entangled systems in strong flows. Hence, a comprehensive examination of the theoretical developments has not been possible. The experiments described in this paper use the filament stretching rheometer to obtain transient extensional stress growth data and steady state uniaxial extensional viscosity data for a number of entangled, narrow molecular weight distribution polystyrene solutions in the strain-rate regime characterized by a significant degree of both chain alignment and stretch. These results are then compared with theoretical predictions for a number of the current generation of reptation-based models, including mechanisms for chain stretching, contour length fluctuations, and convective constraint release. These comparisons demonstrate that when the model parameters are properly obtained from linear viscoelastic measurements, the recent model due to Mead, Larson, and Doi (Macromolecules 1998, 31, 7895) provides quantitative predictions for this class of flows for solutions spanning the complete range from very lightly to highly entangled solutions.

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Rheology of star polymers in concentrated solutions and melts

Cited by 188 publications

References 10 publications

Challenges in Multiscale Modeling of Polymer Dynamics

Challenges in Multiscale Modeling of Polymer Dynamics

Rheology of Star-Branched Polyisobutylene

Extensional Rheometry of Entangled Solutions

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