Dynamic birefringence of amorphous polymers

Osaki, Kunihiro; Inoue, Tadashi; Hwang, Eui-Jeong; Okamoto, Hiroyuki; Takiguchi, Osamu

doi:10.1016/0022-3093(94)90586-x

Cited by 32 publications

(32 citation statements)

References 35 publications

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“…The shift factor for the R component reduced to T r 0 , a TR 0 , shows a weaker temperature dependence than that for the G component, a TG 0 . This feature is widely observed in other polymer systems of high M. 16 The shift factor for A1000 shows weaker temperature dependence compared to a TG 0 for the other polymers. The difference between T r 0 and the glass transition temperature, T g , is 16°C for A1000 and about 12°C for the others.…”

Section: Behavior Of Component Functionsmentioning

confidence: 84%

Viscoelasticity of low molecular weight polystyrene. Separation of rubbery and glassy components

Inoue

Onogi

Yao

et al. 1999

J. Polym. Sci. B Polym. Phys.

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The complex shear modulus was measured for four low molecular‐weight polystyrenes (Mw = 10,500, 5970, 2630, and 1050) near and above the glass transition temperature. For the lowest molecular weight sample, the method of reduced variables, the time–temperature superposition principle, was applicable, while it was not applicable for the higher M samples. For these higher M samples, it was assumed that the complex modulus is composed of two components (R and G components). The R component was estimated by subtracting the G component, which was assumed to be the same as the modulus of the lowest molecular weight sample. The time–temperature superposition principle was applicable to each of the R and G components, and the shift factors were different from each other. The contribution of the R component to the total complex modulus decreased with decreasing M. Anomalous temperature dependence of the steady‐state compliance for low M polymers as Plazek reported could be attributed to difference in temperature dependence of the two components. The estimated complex modulus for the R component was in accord with that calculated by spring‐bead model theory. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 389–397, 1999

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Section: Behavior Of Component Functionsmentioning

confidence: 84%

Viscoelasticity of low molecular weight polystyrene. Separation of rubbery and glassy components

Inoue

Onogi

Yao

et al. 1999

J. Polym. Sci. B Polym. Phys.

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“…The stronger temperature dependence for the G component is widely observed in our previous studies. 29 The different temperature dependence between the R and G components implies the failure of thermo-rheological simplicity for viscoelastic functions in the glass transition zone. The true composite curve for E*() at any given temperature can be obtained from the composite curves for the two component functions and temperature dependence.…”

Section: Comparison With Previous Studiesmentioning

confidence: 99%

Viscoelasticity and birefringence of syndiotactic polystyrene. I. Dynamic measurement in supercooled state

Inoue

Ryu

Osaki

et al. 1999

J. Polym. Sci. B Polym. Phys.

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Dynamic viscoelasticity and dynamic birefringence measurements were performed on a quenched amorphous sample of a syndiotactic polystyrene, sPS. The measurements were carried out at temperatures where crystallization did not occur above the glass transition temperature. The data were analyzed with a modified stress‐optical rule: The complex Young's modulus was separated into two components, designated with subscripts R and G, for which the ordinary stress‐optical rule held well individually. A comparison with the results for a conventional amorphous atactic polystyrene has shown that the stereoregularity of sPS enhances the stiffness of main chain and then increases the optical anisotropy of segments. This conclusion is in accord with theoretical calculation on coil dimension and optical anisotropy. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 399–404, 1999

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“…64 It is also common during viscoelastic experiments on polymers. [65][66][67][68] The strain dependence of the stress optical coefficient implicit in eq 17 can give rise to the zero-stress birefringence observed for the double networks. The basic hypothesis of double networks is that the stresses are additive.…”

Section: Discussionmentioning

confidence: 99%

Mechanical and Optical Behavior of Double Network Rubbers

Mott

Roland

2000

Macromolecules

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Stress, strain, and optical birefringence were measured for a series of peroxide-cured natural rubbers, having both isotropic and double network structures. The residual stretch (permanent set) for the latter ranged from 2.0 to 4.5, with elastic moduli that were an increasing function of this residual strain, as found in previous works. A small birefringence, ca. 10 -5 , was observed for the unstressed double networks, and its magnitude increased with increasing residual strain. The sign of this birefringence corresponded to extension of the (undeformed) double networks. Under stress, the birefringence followed the stress optical law. The double network properties were interpreted using the constrained-chain model of rubber elasticity, with the assumption of independent, additive contributions from the two component networks. The calculated results differed from the experimental findings, in particular underestimating the residual strain. This failure is a consequence of the overprediction of the stresses during compression, a limitation common to molecular theories of rubber elasticity. The modeling of the double networks does account qualitatively for the sign of their unstressed birefringence, which is due to the stressoptical coefficient being larger in tension than in compression. This particular deviation from the stressoptical law is known from both theory and experiment.

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Dynamic birefringence of amorphous polymers

Cited by 32 publications

References 35 publications

Viscoelasticity of low molecular weight polystyrene. Separation of rubbery and glassy components

Viscoelasticity of low molecular weight polystyrene. Separation of rubbery and glassy components

Viscoelasticity and birefringence of syndiotactic polystyrene. I. Dynamic measurement in supercooled state

Mechanical and Optical Behavior of Double Network Rubbers

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