Limit of validity of the stress-optical rule for polystyrene melts: Influence of polydispersity

Luap, Clarisse; Karlina, M. V.; Schweizer, T.; Venerus, David C.

doi:10.1016/j.jnnfm.2006.05.009

Cited by 17 publications

(20 citation statements)

References 16 publications

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“…Consistency with the stress-optic rule (for moderate deformations). It is well established experimentally [38] that polymer melts show a linear relationship between the stress tensor and the refractive index tensor when the chains are Gaussian [53,54]. The dependence of the refractive index tensor on chain conformations has a straightforward derivation [55], so we assume that it is correct.…”

Section: Consistency With Nonequilibrium Thermodynamicsmentioning

confidence: 99%

Fluctuating Entanglements in Single-Chain Mean-Field Models

2013

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Abstract:We consider four criteria of acceptability for single-chain mean-field entangled polymer models: consistency with a multi-chain level of description, consistency with nonequilibrium thermodynamics, consistency with the stress-optic rule, and self-consistency between Green-Kubo predictions and linear viscoelastic predictions for infinitesimally driven systems. Each of these topics has been considered independently elsewhere. However, we are aware of no molecular entanglement model that satisfies all four criteria simultaneously. Here we show that an idea from Ronca and Allegra, generalized to arbitrary flows, can be implemented in a slip-link model to create a model that does satisfy all four criteria. Aside from the direct benefits of agreement, the result modifies the relation between the initial relaxation modulus G(0) and the entanglement molecular weight M e . If this implementation is correct, current estimates for M e would require modification that brings their values more in line with estimates based on topological analysis of molecular dynamics simulations.

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Section: Consistency With Nonequilibrium Thermodynamicsmentioning

confidence: 99%

Fluctuating Entanglements in Single-Chain Mean-Field Models

2013

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“…Luap et al [37] extended this study to polystyrene melts with narrow molecular weight distributions and found a violation of the rule above a critical stress of about 2.7 MPa, independent of temperature and strain rate contrary to polydisperse systems. Very recently, they have further examined the effect of polydispersity on the validity of the stress-optical rule and reported a critical stress increasing with increasing Deborah number towards the value measured for quasi-monodisperse polystyrene melts [36]. At large stress levels, the violation of the stress-optical rule can be due to several effects such as the chain finite extensibility [35][36][37][38].…”

Section: Stress-optical Rulementioning

confidence: 99%

“…investigated the validity of the stress-optical rule in uniaxial elongation for a commercial grade of a polystyrene melt and showed that it was followed for stresses below roughly 1 MPa [35]. The failure of the rule was shown to be dependent on temperature and strain rate [35,36]. Luap et al [37] extended this study to polystyrene melts with narrow molecular weight distributions and found a violation of the rule above a critical stress of about 2.7 MPa, independent of temperature and strain rate contrary to polydisperse systems.…”

Section: Stress-optical Rulementioning

confidence: 99%

Lubricated optical rheometer for the study of two-dimensional complex flows of polymer melts

Soulages

Schweizer

Venerus

et al. 2008

Journal of Non-Newtonian Fluid Mechanics

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“…[1][2][3][4] This linear relation is called the stress-optic rule (SOR). 2 For Gaussian chains, the traction force of a chain strand whose ends are constrained by entanglements is a linear function of the strand's end-to-end vector, so that the stress tensor of the polymer melt is proportional to the second-moment of the strand's orientation vector.…”

mentioning

confidence: 99%

“…If the polymer chain is stretched beyond the Gaussian regime, SOR is violated because of the breakdown of the linear relation between the traction and the end-to-end length of the strand. 3,4 The tube model of entangled polymers assumes that the lateral motion of the polymer chain in the melt is prohibited, as if the chains were confined in a tube-like domain. 6 The origin of the stress of the material is usually assumed to be the traction force of the chain strand along the tube.…”

mentioning

confidence: 99%

Correction of Doi-Edwards' Green function for a chain in a harmonic potential and its implication for the stress-optic rule

Schieber¹,

Indei²,

Dearborn³

2014

J. Polym. Sci. Part B: Polym. Phys.

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We show that the stress-optic rule is violated in a theoretical model of polymer melts that uses a harmonic potential to confine a polymer chain in a tube-like domain of surrounding entangled polymers. This is the model first proposed by Doi and Edwards (DE) [J. Chem. Soc. Farad. Trans. II 1978, 74, 1802 and later extended by Ianniruberto and Marrucci (IM) [J. Non-Newton. Fluid Mech. 1998, 79, 225]. We first provide a rigorous Green function for such a chain, which is a correction to that derived by DE. The modification guarantees chain continuity. Second, we show that the stress-optic rule is violated in the IM model if the modified Green function is used and an unnecessary assumption employed by IM is avoided. Our result contradicts that of IM. The violation is due to the presence of the virtual springs to confine the chain in the tube rather than the anisotropy of the confinement potential. On the other hand, DE used the virtual-spring model only for estimation of the monomer density along the primitive path where we find just a small correction. As they did not use it for rheological calculations, the stress-optic rule appears to be safe for the Doi-Edwards model. The result might be useful for extracting tube potentials from atomistic simulations.

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Limit of validity of the stress-optical rule for polystyrene melts: Influence of polydispersity

Cited by 17 publications

References 16 publications

Fluctuating Entanglements in Single-Chain Mean-Field Models

Fluctuating Entanglements in Single-Chain Mean-Field Models

Lubricated optical rheometer for the study of two-dimensional complex flows of polymer melts

Correction of Doi-Edwards' Green function for a chain in a harmonic potential and its implication for the stress-optic rule

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