Apparatus for the Measurement of the Dynamic Shear Modulus and Hysteresis of Rubber at Low Frequencies

Fletcher, W. P.; Gent, A. N.

doi:10.5254/1.3539794

Cited by 13 publications

(14 citation statements)

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“…However, this modulus enhancement is extremely sensitive to strain, and this network breakdown due to application of small strains is generally called the Payne effect 2 or the Fletcher-Gent effect. 47 It was recently revealed that the strain dependence noted in the unjamming process (Payne effect) of particle-filled rubber is strikingly similar to the influence of temperature on the glass transition of materials, 4, 48-51 because deformation can act as an effective temperature in jammed particle-filled materials and granular solids. 48,49,[52][53][54][55] It was mentioned earlier that much of the filler network develops during the filler flocculation process which can occur upon heating the compounds.…”

Section: Flocculation Reinforcement and Glass Transition Effects 511mentioning

confidence: 99%

Flocculation, Reinforcement, and Glass Transition Effects in Silica-Filled Styrene-Butadiene Rubber

Robertson

Lin

Bogoslovov

et al. 2011

Rubber Chemistry and Technology

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The introduction of silanes to improve processability and properties of silica-reinforced rubber compounds is critical to the successful commercial use of silica as a filler in tires and other applications. The use of silanes to promote polymer-filler interactions is expected to limit the development of a percolated filler network and may also affect the mobility of polymer chains near the particles. Styrene-butadiene rubber (SBR) was reinforced with silica particles at a filler volume fraction of 0.19, and various levels of filler-filler shielding agent (n-octyltriethoxysilane) and polymerfiller coupling agent (3-mercaptopropyltrimethoxysilane) were incorporated. Both types of silane inhibited the filler flocculation process during annealing the uncured rubber materials, thus reducing the magnitude of the Payne effect. In contrast to the significant reinforcement effects noted in the strain-dependent shear modulus, the bulk modulus from hydrostatic compression was largely unaltered by the silanes. Addition of polymer-filler linkages using the coupling agent yielded bound rubber values up to 71%; however, this bound rubber exhibited glass transition behavior which was similar to the bulk SBR response, as determined by calorimetry and viscoelastic testing. Modifying the polymer-filler interface had a strong effect on the nature of the filler network, but it had very little influence on the segmental dynamics of polymer chains proximate to filler particles.

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Section: Flocculation Reinforcement and Glass Transition Effects 511mentioning

confidence: 99%

Flocculation, Reinforcement, and Glass Transition Effects in Silica-Filled Styrene-Butadiene Rubber

Robertson

Lin

Bogoslovov

et al. 2011

Rubber Chemistry and Technology

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“…Finally, values of H' are calculated from eq. (9). Typical relations between H' and input energy W , obtained in this way are represented in Figure 4 by a broken curve.…”

Section: Combined Effects Of Stress Softening and Energy Dissipation mentioning

confidence: 99%

“…Neglecting the relatively small proportion of strain energy stored in the hard phase, we assume that a fraction H,W2 of the energy Wz is dissipated in processes which take place in the soft phase, where H, is the energy loss ratio for unfilled rubber at an energy input of Wz. Thus, the overall dissipation ratio H', defined by (W1 -WZ')/Wl, will be given by (9) where H is obtained from eqs. (3) and (4).…”

Section: Combined Effects Of Stress Softening and Energy Dissipation mentioning

confidence: 99%

Energy dissipation in stretching filled rubbers

Gent

1974

J. Appl. Polym. Sci.

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SynopsisEnergy expended irreversibly in stretching filled rubbers is calculated for a simple two-phase series model: a soft phase resembling the corresponding unfilled rubber and a hard phase in series with the soft phase. It is assumed that the Iubber is initially wholly in the hard state and that it changes progressively into the softened state on stretching, as proposed by Mullins and Tobin. For a wide range of model parameters, the dissipation of mechanical energy is predicted to rise to about 40% of the input energy at large strains. This predicted behavior is in reasonably good agreement with observations of extra energy dissipat,ion in carbon black-filled rubbers, in comparison with corresponding unfilled rubbers, suggesting that the proposed mechanism of hysteresis by phase transformation is valid. A method of combining energy losses from two simultaneous dissipative processes is also proposed.

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“…At all strains, stress amplification in the vicinity of the inextensible particles increases the modulus; 13,14 however, when the filler concentration is sufficiently high, a network structure forms, giving rise to a larger and strongly nonlinear modulus. [15][16][17][18] The nonlinearity is due to the mechanical lability of the flocculated particle structure, the breakup of which is governed by the strain energy. [19][20][21] Interaction of the polymer chains in the vicinity of the filler interface can be expected to influence the former's local segmental dynamics, and there are various reports of glassy behavior induced in rubbery material due to proximity of filler particles such as carbon black.…”

Section: Introductionmentioning

confidence: 99%

Structural Arrest and Thermodynamic Scaling in Filler-Reinforced Polymers

Robertson¹,

Bogoslovov

Roland

2009

Rubber Chemistry and Technology

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The role of small silica particles on the stiffness and glass transition dynamics of polyvinylacetate (PVAc) was examined for filler volume fraction (φ) from 0 to 0.28. Whereas the influences of bound polymer and a strain-dependent filler network were clearly noted in the shear properties, the only effect of filler on the bulk modulus was the reduction in deformable polymer. The calorimetric glass transition of PVAc and its dependence on cooling rate were unaltered by the presence of the silica, in agreement with previous dielectric relaxation results. In contrast to the temperature dependence of the segmental dynamics, which was independent of φ, the effect of volume on segmental relaxation was amplified by the addition of silica. This resulted in larger values for the thermodynamic scaling exponent (γ), which also increased sharply at the filler concentration corresponding to the development of a percolated filler network.

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Apparatus for the Measurement of the Dynamic Shear Modulus and Hysteresis of Rubber at Low Frequencies

Cited by 13 publications

References 0 publications

Flocculation, Reinforcement, and Glass Transition Effects in Silica-Filled Styrene-Butadiene Rubber

Flocculation, Reinforcement, and Glass Transition Effects in Silica-Filled Styrene-Butadiene Rubber

Energy dissipation in stretching filled rubbers

Structural Arrest and Thermodynamic Scaling in Filler-Reinforced Polymers

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