Rise of Temperature on Fast Stretching of Synthetics and Natural Rubbers

Dart, S. L.; Anthony, R. L.; Guth, Eugene

doi:10.1021/ie50395a020

Cited by 51 publications

(17 citation statements)

References 2 publications

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“…11), is expected. These values of ATare reasonable comparing with 2.06 K for Neoprene at D=2.0 and 0.42 K for Latex at D=2.0 [6].…”

Section: Silicone Rubbersupporting

confidence: 84%

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Instantaneous strain recovery elasticity and endothermic heat change in nylon-6 monofilaments and silicone rubbers

Tanaka

1996

Journal of Thermal Analysis

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The instantaneous elastic moduli for a nylon-6 monofilament were derived on strain recoveries fight after creep, stress relaxation, and rapid elongation, Ec, E8 and E~, respectively. It was found that during strain recovery Es(>E~) and E~ increase monotonically with increasing load, ml, on the sample. The extrapolated value of Es at ml =0 g is almost equal to Young's modulus, 4.06 GPa. The value of Er also increased with increasing ml, and at ml=600 g (1.93 tem -2) reached about 14 GPa. The endothermic heat change right after creep, stress relaxation or rapid elongation, Q, was negligibly small. For comparison, E,, Er and Q were also investigated for silicone rubber. It was found that Es (53.8 MPa at the draw ratio D= 1.2) decreased abruptly at D = 1.3. In the range of D = 1.4-1.9, Es was only 22.6 MPa. In the case of stress relaxation, Q increased with increasing D from 4 J mo1-1 (at D= 1.2) to 56 J mol -l (at D= 1.9). Furthermore Er (5.58 MPa at ml = 133.8 g (429.4 kg em-2)) increased gradually with increasing ml and attained 16.6 MPa at ml =548.4 g (1.76 t cm-2). In the ease of creep, Q was in the range of 0-11.5 J moF l and larger when larger loads, m2, were removed during the later stages of creep.

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“…11), is expected. These values of ATare reasonable comparing with 2.06 K for Neoprene at D=2.0 and 0.42 K for Latex at D=2.0 [6].…”

Section: Silicone Rubbersupporting

confidence: 84%

“…For comparison, Q, Es and Ec were investigated for silicone rubber with entropy elasticity [5]. The rubber is exothermic when stretched rapidly and endothermic when the stress is released [6].…”

Section: -4466/96/$ 500 <9 1996 Akad~miai Kiad6 Budapest John Wmentioning

confidence: 99%

Instantaneous strain recovery elasticity and endothermic heat change in nylon-6 monofilaments and silicone rubbers

Tanaka

1996

Journal of Thermal Analysis

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“…23,24 Measurements of the volume dilation accompanying tensile stress 25 are significantly greater than predicted. Actually, the theory predicts that the stress should be strictly proportional to temperature ͑having a T = 0 intercept of zero͒, but this is not what is seen.…”

Section: Introductionmentioning

confidence: 84%

“…2, rotational conformations with shorter end-to-end distance generally have higher energy than the extended states. 23,24 At moderate to high tensile strain, some of the chains must become sensibly straight 39 ͑at least between entangle-ments͒ and the concept of a constraining tube is no longer appropriate. That is, one or more of their dihedral angles will be rotated toward the transition state separating the minimum from an extended conformation.…”

Section: ͑13͒mentioning

confidence: 99%

Quantum chemistry and molecular dynamics studies of the entropic elasticity of localized molecular kinks in polyisoprene chains

Hanson

Martin

2010

The Journal of Chemical Physics

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We investigate the thermodynamic consequences of the distribution of rotational conformations of polyisoprene on the elastic response of a network chain. In contrast to the classical theory of rubber elasticity, which associates the elastic force with the distribution of end-to-end distances, we find that the distribution of chain contour lengths provides a simple mechanism for an elastic force. Entropic force constants were determined for small contour length extensions of chains constructed as a series of localized kinks, with each kink containing between one and five cis-1,4-isoprene units. The probability distributions for the kink end-to-end distances were computed by two methods: (1) by constructing a Boltzmann distribution from the lengths corresponding to the minimum energy dihedral rotational conformations, obtained by optimizing isoprene using first principles density functional theory, and (2) by sampling the trajectories of molecular dynamics simulations of an isolated molecule composed of five isoprene units. Analogous to the well-known tube model of elasticity, we make the assumption that, for small strains, the chain is constrained by its surrounding tube, and can only move, by a process of reptation, along the primitive path of the contour. Assuming that the chain entropy is Boltzmann's constant times the logarithm of the contour length distribution, we compute the tensile force constants for chain contour length extension as the change in entropy times the temperature. For a chain length typical of moderately crosslinked rubber networks (78 isoprene units), the force constants range between 0.004 and 0.033 N/m, depending on the kink size. For a cross-linked network, these force constants predict an initial tensile modulus of between 3 and 8 MPa, which is comparable to the experimental value of 1 MPa. This mechanism is also consistent with other thermodynamic phenomenology.

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“…A 0. At large strain, the behavior could be expressed only by a large number of terms with arbitrary coefficients for Equation (39).…”

Section: Phenomenological Approach To Rubber Elasticitymentioning

confidence: 99%

Thermodynamics, Thermal Effects and Dilatation of Natural Rubber

Boel¹,

Eirich²

1966

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3.The contributions by the i.hains to the total retractive force are additive.4. The deformation of the chains must be af'ine to the deformation of the sample, which takes place at constant volume.As stated these approxim&tions are rather restrictive and tend to oversimplify many features.Recently, the consequences of one of the major assumptions underlying the simple Gaussian treatment -namely that the chains are volumeless and do not hinder each other -have been reappraised [111. Taking the volume of the chains into account effects the conformadonai entropy of the network.

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Rise of Temperature on Fast Stretching of Synthetics and Natural Rubbers

Cited by 51 publications

References 2 publications

Instantaneous strain recovery elasticity and endothermic heat change in nylon-6 monofilaments and silicone rubbers

Instantaneous strain recovery elasticity and endothermic heat change in nylon-6 monofilaments and silicone rubbers

Quantum chemistry and molecular dynamics studies of the entropic elasticity of localized molecular kinks in polyisoprene chains

Thermodynamics, Thermal Effects and Dilatation of Natural Rubber

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