A Novel Look at Models for Polymer Entanglement

Heymans, Nicole Verheulpen

doi:10.1021/ma9911849

Cited by 69 publications

(74 citation statements)

References 22 publications

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“…The average end-to-end distance R e of PEO polymer chains with M w = 43 000 g mol −1 can be calculated to be 19 nm. 24 The melting temperature of bulk PEO is 338 K. The PEO films were placed onto the AAO templates in order to carry out the infiltration by the "precursor film" infiltration method. 25,26 In this method, a polymeric liquid precursor film spreads over the whole surface of the AAO template, pore walls included.…”

Section: Infiltration Of Poly"ethylene Oxide… Into the Nanoporesmentioning

confidence: 99%

Neutron scattering study of the dynamics of a polymer melt under nanoscopic confinement

Krutyeva

Muñoz-Martı́n

Arbe

et al. 2009

The Journal of Chemical Physics

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Poly(ethylene oxide) confined in an anodic aluminum oxide solid matrix has been studied by different neutron scattering techniques in the momentum transfer (Q⃗) range 0.2≤Q=|Q⃗|≤1.9 Å−1. The cylindrical pores of the matrix present a diameter (40 nm) much smaller than their length (150 μm) and are parallel and hexagonally ordered. In particular, we investigated the neutron intensity scattered for two orientations of the sample with respect to the incident beam, for which the Q⃗ direction was either parallel or perpendicular to the pores for a scattering angle of 90°. Diffuse neutron scattering at room temperature has shown that the aluminum oxide has amorphous structure and the polymer in the nanoporous matrix is partially crystallized. Concerning the dynamical behavior, for Q<1 Å−1, the spectra show Rouse-like motions indistinguishable from those in the bulk within the uncertainties. In the high-Q limit we observe a slowing down of the dynamics with respect to the bulk behavior that evidences an effect of confinement. This effect is more pronounced for molecular displacements perpendicular to the pore axis than for parallel displacements. Our results clearly rule out the strong corset effect proposed for this polymer from nuclear magnetic resonance (NMR) studies and can be rationalized by assuming that the interactions with the pore walls affect one to two adjacent monomer monolayers.

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Section: Infiltration Of Poly"ethylene Oxide… Into the Nanoporesmentioning

confidence: 99%

Neutron scattering study of the dynamics of a polymer melt under nanoscopic confinement

Krutyeva

Muñoz-Martı́n

Arbe

et al. 2009

The Journal of Chemical Physics

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“…Notably, the most successful of them are based on similar [38][39][40][41] ideas. A good correlation with polymer melt data is provided by the packing length 42 model, which is based on the conjecture of Lin, 43 and Kavassalis and Noolandi.…”

Section: Introductionmentioning

confidence: 99%

Microscopic Description of Entanglements in Polyethylene Networks and Melts: Strong, Weak, Pairwise, and Collective Attributes

2012

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Abstract:We present atomistic molecular dynamics simulations of two Polyethylene systems where all entanglements are trapped: a perfect network, and a melt with grafted chain ends. We examine microscopically at what level topological constraints can be considered as a collective entanglement effect, as in tube model theories, or as certain pairwise uncrossability interactions, as in slip-link models.A pairwise parameter, which varies between these limiting cases, shows that, for the systems studied, the character of the entanglement environment is more pairwise than collective. We employ a novel methodology, which analyzes entanglement constraints into a complete set of pairwise interactions, similar to slip links. Entanglement confinement is assembled by a plethora of links, with a spectrum of confinement strengths, from strong to weak. The strength of interactions is quantified through a link 'persistence', which is the fraction of time for which the links are active. By weighting links according to their strength, we show that confinement is imposed mainly by the strong ones, and that the weak, trapped, uncrossability interactions cannot contribute to the low frequency modulus of an elastomer, or the plateau modulus of a melt. A selfconsistent scheme for mapping topological constraints to specific, strong binary links, according to a given entanglement density, is proposed and validated. Our results demonstrate that slip links can be viewed as the strongest pairwise interactions of a collective entanglement environment. The methodology developed provides a basis for bridging the gap between atomistic simulations and mesoscopic slip link models.

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“…The total number of entanglement for the ith component in the blend (N i ) is given by the equation (13) where M i is the molecular weight of the ith component. Therefore, M e of the ith component in the blend can be determined by…”

Section: Determination Of Individual Molecular Parametersmentioning

confidence: 99%

“…Although Aharoni's chain stiffness parameters and M e 's of a large number of polymers support this relationship, 9 it was shown later by Fetters et al 12 that the relation C ϱ ϰ N e 0.5 is imprecise because N e increases with temperature while C ϱ can either remain constant, decrease, or increase. Various polymer entanglement models were reviewed by Heymans,13 who demonstrated that the Fetters 12 and the ColbyRubinstern 14 models are applicable. In the present work, the Fetters model, which relates plateau modulus to packing length, from which ͗R 2 ͘/M w can be estimated, will be preferred for its ease of use.…”

Section: Introductionmentioning

confidence: 99%

“…A topological classification of entanglements was proposed more recently and expresses itself through a variety of values of M e obtained from the plateau modulus. 13 A way to look at things is to extract directly M e1 and M e2 , the molecular weights between entanglements of polymers 1 and 2 of the blends, for which Tsenoglou proposed an approach. 6 The equivalent is, however, not possible at this time for .…”

Section: Introductionmentioning

confidence: 99%

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Rheological quantification of molecular parameters: Application to a hydrogen bond forming blend

Cai

Aı̈t-Kadi

Brisson

2004

J of Applied Polymer Sci

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ABSTRACT:The component dynamics and molecular parameters were investigated for miscible poly(4-vinyl phenol)/poly(ethylene oxide) (PVPh/PEO) blends. Global values of molecular weight between entanglements (M e ) were first estimated for the blends and were compared with existing athermal model predictions. Global interchain friction coefficients () of the blends were deduced from the zeroshear viscosity. A maximum was observed at a composition of 20 -30 wt % of PEO. Chain dimensions of this phase are estimated by using a relationship between the plateau modulus and a packing length (i.e., number of individual chains present in a given small volume of the melt). A slight increase in M e is observed at low PEO weight fraction (before 0.20), followed by a sharp decrease in M e values after this concentration. Values of in PVPh/PEO blends show a maximum value at 20 -30 wt % of PEO.

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A Novel Look at Models for Polymer Entanglement

Cited by 69 publications

References 22 publications

Neutron scattering study of the dynamics of a polymer melt under nanoscopic confinement

Neutron scattering study of the dynamics of a polymer melt under nanoscopic confinement

Microscopic Description of Entanglements in Polyethylene Networks and Melts: Strong, Weak, Pairwise, and Collective Attributes

Rheological quantification of molecular parameters: Application to a hydrogen bond forming blend

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