Short-Range Order in Deformed Polymer Networks

Tanaka, Takeshi; Allen, Geoffrey

doi:10.1021/ma60056a035

Cited by 58 publications

(42 citation statements)

References 11 publications

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“…These studies of stress on the atomic level lead to the conjecture that the deviatoric stress is primarily due to the steric effects associated with the hard core repulsive portion of interatomic interactions and that these are primarily entropic. Further work is needed to examine this conjecture which, it appears, bears some relation to the consideration of packing entropy effects 23,24 in addition to the configurational entropy considerations that underlay the ESSF.…”

Section: A Rubber Elasticitymentioning

confidence: 99%

Toward a unified view of stress in small-molecular and in macromolecular liquids

Picu

Loriot²,

Weiner

1999

The Journal of Chemical Physics

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Interfacial tension behavior of binary and ternary mixtures of partially miscible Lennard-Jones fluids: A molecular dynamics simulation A molecular dynamics study of macromolecules in good solvents: Comparison with dielectric spectroscopy experimentsWe consider a family of molecular liquids, each consisting of linear molecules with N covalent bonds, focusing specifically on Nϭ1 ͑diatomic liquid͒, Nϭ3 ͑four-atom molecular liquid͒, and Nϭ200 ͑macromolecular liquid͒. The bonded and nonbonded potentials, u b (r) and u nb (r), are the same for each system, with u b representing stiff linear springs and u nb corresponding to the repulsive portion of the Lennard-Jones potential. The relaxation of the stress difference , following a constant-volume elongation of the system, is determined in terms of interatomic interactions by nonequilibrium molecular dynamics simulations. It is found that the nonbonded interactions make the principal contribution to while the bonds make a negative contribution. For all systems studied it is found that, following a short induction period after the start of relaxation, ϭC͗͗P 2 ( b )͘͘, where ͗͗P 2 ( b )͘͘(t) is a measure of the individual bond orientation and the proportionality constant Cϭ3.5 within simulation accuracy, for Nу3. The principal difference between the behavior for small and large N is the rate at which ͗͗P 2 ( b )͘͘(t) decays. An explanation of the broad applicability of the relation ϭC͗͗P 2 ( b )͘͘ is presented in terms of the concepts of steric shielding, intrinsic interaction distributions, and intrinsic stresses. The failure of this relation during the short induction period is explained in terms of anisotropies in atom distributions present immediately after deformation.

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Section: A Rubber Elasticitymentioning

confidence: 99%

Toward a unified view of stress in small-molecular and in macromolecular liquids

Picu

Loriot²,

Weiner

1999

The Journal of Chemical Physics

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“…52,53 Several experimental and theoretical studies showed that the polymeric systems with finite nematic interaction exhibited larger stress-optical coefficients than those calculated from the density fluctuation theory. [66][67][68][69][70] Using a theta solvent for the constituent polymer for gel specimens enables us to exclude the excluded volume effect. These experiments will elucidate whether the nematic and/or excluded volume interaction significantly influences the cross effect in the Tetra-PEG gels, but they are beyond the range of this paper.…”

Section: Conjecture On the Origin Of The Cross Effect Of Strainsmentioning

confidence: 99%

Probing the cross-effect of strains in non-linear elasticity of nearly regular polymer networks by pure shear deformation

Katashima

Urayama

Chung

et al. 2015

The Journal of Chemical Physics

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The pure shear deformation of the Tetra-polyethylene glycol gels reveals the presence of an explicit cross-effect of strains in the strain energy density function even for the polymer networks with nearly regular structure including no appreciable amount of structural defect such as trapped entanglement. This result is in contrast to the expectation of the classical Gaussian network model (Neo Hookean model), i.e., the vanishing of the cross effect in regular networks with no trapped entanglement. The results show that (1) the cross effect of strains is not dependent on the network-strand length; (2) the cross effect is not affected by the presence of non-network strands; (3) the cross effect is proportional to the network polymer concentration including both elastically effective and ineffective strands; (4) no cross effect is expected exclusively in zero limit of network concentration in real polymer networks. These features indicate that the real polymer networks with regular network structures have an explicit cross-effect of strains, which originates from some interaction between network strands (other than entanglement effect) such as nematic interaction, topological interaction, and excluded volume interaction.

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Great efforts were devoted to describing the strain-stress relationship for polymer networks which are in the isotropic phase and far from isotropic-to-nematic (I-N) phase transition. [1][2][3][4][5][6][7][8][9] It have been shown experimentally [1] that strain-stress behaviour of nematic elastomers deviates from theoretical predictions of gas-like theory of rubber elasticity developed in ref. [20][21][22][23][24][25][26] for ordinary elastomers.…”

Section: Introductionmentioning

confidence: 99%

“…This effect is caused by nematic-like interactions which affect significantly the elastic properties of polymers even at temperatures higher than the temperature of the I-N phase transition, T t . [2][3][4][5][6][7][8][9] The shape of a nematic elastomer under an external stress changes step-wise at the temperature T t of a I-N Full Paper: A simplified "three-chain" network model formed from freely jointed polymer chains consisting of Gaussian elements with fixed mean-square lengths is proposed for describing local dynamic properties of nematic elastomers. The boundaries of a polymer network are supposed to be fixed when sample volume and shape do not change with ordering.…”

Section: Introductionmentioning

confidence: 99%

The Estimation of Statistical Parameters Determining the Relaxation Times of Nematic Elastomers: A Three-Chain Network Model

Gotlib

Torchinskii

Toshchevikov³

2002

Macromol. Theory Simul.

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Short-Range Order in Deformed Polymer Networks

Cited by 58 publications

References 11 publications

Toward a unified view of stress in small-molecular and in macromolecular liquids

Toward a unified view of stress in small-molecular and in macromolecular liquids

Probing the cross-effect of strains in non-linear elasticity of nearly regular polymer networks by pure shear deformation

The Estimation of Statistical Parameters Determining the Relaxation Times of Nematic Elastomers: A Three-Chain Network Model

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