Tensile stress relaxation behavior of partly to completely acetylated polyvinyl alcohol polymers

Fujino, Kiyohisa; Horino, Tsuneo; Miyamoto, Kihachiro; Kawai, Hiromichi

doi:10.1016/0095-8522(61)90039-3

Cited by 21 publications

(6 citation statements)

References 22 publications

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“…Some mid-PI chains, which roughly entangle, would be responsible for this relaxation. On the contrary, the long relaxation time reflects the relaxation of the deformed hard PS spheres because there is no peak in such a long-relaxation time zone in the case of a simple uncrosslinked polymer . Furthermore, it is noteworthy that the relaxation spectrum for the specimen with 23 wt % tackifier content does not exhibit a decreasing tendency in the longer-relaxation time zone.…”

Section: Resultsmentioning

confidence: 96%

“…The broad peak at τ = 1.5 s can be considered as stress relaxation due to the quick motion of the segments of the mid-PI chains. Nevertheless, the continuous spectrum around τ = 1–10 s reminds the stress relaxation of the deformed uncrosslinked polymer network . Namely, the deformed mid-PI chains (with both the bridge and loop conformations) can be considered to relax.…”

Section: Resultsmentioning

confidence: 99%

“…On the contrary, the long relaxation time reflects the relaxation of the deformed hard PS spheres because there is no peak in such a long-relaxation time zone in the case of a simple uncrosslinked polymer. 45 Furthermore, it is noteworthy that the relaxation spectrum for the specimen with 23 wt % tackifier content does not exhibit a decreasing tendency in the longer-relaxation time zone. This clearly indicates that the specimen does not flow macroscopically, further implying that there may be a rare occurrence of the pulling out of the PS block chains from its spherical microdomains.…”

Section: Stress-relaxationmentioning

confidence: 90%

“…Nevertheless, the continuous spectrum around τ = 1−10 s reminds the stress relaxation of the deformed uncrosslinked polymer network. 45 Namely, the deformed mid-PI chains (with both the bridge and loop conformations) can be considered to relax. Some mid-PI chains, which roughly entangle, would be responsible for this relaxation.…”

Section: Stress-relaxationmentioning

confidence: 99%

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Stress–Strain and Stress-Relaxation Behaviors of Solution-Coated Layers Composed of Block Copolymers Mixed with Tackifiers

et al. 2021

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The relationship between the mechanical properties and the structure of block copolymers mixed with tackifiers whose relative solubility to the respective components of block copolymers differs was examined. Coated layers were prepared by solution coating using a block copolymer composed of polystyrene (PS) and polyisoprene (PI), which forms spherical microdomains of PS in the PI matrix, mixed with three types of tackifiers: aliphatic (C5) resin, aliphatic−aromatic (C5−C9) resin, and rosin ester (RE) resin. Furthermore, the correlation between the changes in the nanostructure and mechanical properties including the stress-relaxation behaviors was clarified by twodimensional small-angle X-ray scattering measurement. The amount of the PI-bridge conformation in the case of C5 resin is the lowest, resulting in the lowest stress. On the contrary, the largest amount of RE resin was solubilized in the PS phase so that it can be considered that pulling out of the PS chains took place easily. We were able to explain the stress-relaxation behavior by fitting with the three-component exponent functions. The triple exponential decay functions indicate the hierarchy of the structures that are the origins of the ″fast mode″ relating to the local relaxation due to the rotation of the repeating unit of polymer chains; the ″intermediate mode″ of the disentanglement of the mid-PI chains; and the ″slow mode″ relating to, in this particular case, pulling out of the PS chains from the PS sphere.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: Stress-relaxationmentioning

confidence: 90%

Section: Stress-relaxationmentioning

confidence: 99%

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Stress–Strain and Stress-Relaxation Behaviors of Solution-Coated Layers Composed of Block Copolymers Mixed with Tackifiers

et al. 2021

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“…There are three main categories: diblock copolymers, sometimes referred to as AB block copolymers, (Fujino et al, 1961).…”

Section: Behaviour Of Copolymersmentioning

confidence: 99%

A methodology for developing high damping materials with application to noise reduction of railway track

Ahmad

2009

The Journal of the Acoustical Society of America

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For application in damping treatments, elastomeric materials should have a high damping loss factor, but this is inevitably linked to a strong temperature-dependence of the dynamic properties. A methodology is developed that allows a material to be formulated for a particular damping application where temperature-dependence has to be taken into account. The methodology is applied to the case of a tuned absorber system used for damping the vibration of a railway track. This is required to be effective over a temperature range -20 to 40 .To investigate the effect of the temperature on the performance of a rail damper, a simple Timoshenko beam model of the track vibration is used, to which are added single-frequency and dual-frequency tuned absorbers. The results show that a high noise reduction can be achieved for the optimum stiffness, provided that the loss factor is between about 0.25 and 0.4.In order to study the generic effects of high damping versus constant stiffness, the time-temperature superposition principle is used to convert frequency-dependence to temperature-dependence for a notional material with constant loss factor. This is used in the prediction of decay rates and thereby noise reduction. In addition, a weighted noise reduction is studied by using measured rail temperature distributions. This temperatureweighted noise reduction allows a single number measure of performance to be obtained which can be used to assess various elastomeric materials in order to determine the optimum material for a given situation.Two types of viscoelastic material, butyl and EPDM rubbers with various amount of fillers and plasticisers are investigated. The properties of both rubbers have been measured over the range of temperatures for frequencies 300-3000 Hz. For this a test rig had to be modified. For butyl, the best combination of filler and plasticiser gives temperature weighted noise reductions up to 5.9 dB(A). Butyl rubber is suitable for use in the rail absorber giving high noise reductions between 0 and 40 . The best EPDM compound gives a temperature-weighted noise reduction up to 6.2 dB(A). Comparing these two rubbers, EPDM is more suitable for low temperatures below 10 and butyl is more suitable for higher temperatures above 10 .

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Stress relaxation and hysteresis at various strain rates

Chang

1964

J of Applied Polymer Sci

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SynopsisApplying the Boltzmann superposition principle on a generalized Maxwell model, an analysis of the relations between extension, relaxation, and hysteresis is presented, which shows that any one of these three can be calculated from the other two. It is shown that the relaxation modulus does not vary with strain rate when time is measured from the start of extension, except in the early period of relaxation. It is demonstrated that the first derivative of the ratio of extension stress-strain rate with respect to time is the limiting value of the relaxatjon modulus. The short-time end of relaxation modulustime curve can be readily extended for several decades of logarithm of time without resorting to the temperature effect. The results obtained from the treatment of experimental data on polyisobutylene verify the theoretical deductions, which may also be considered as an additional explicit proof of the Boltemann superposition principle.

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Tensile stress relaxation behavior of partly to completely acetylated polyvinyl alcohol polymers

Cited by 21 publications

References 22 publications

Stress–Strain and Stress-Relaxation Behaviors of Solution-Coated Layers Composed of Block Copolymers Mixed with Tackifiers

Stress–Strain and Stress-Relaxation Behaviors of Solution-Coated Layers Composed of Block Copolymers Mixed with Tackifiers

A methodology for developing high damping materials with application to noise reduction of railway track

Stress relaxation and hysteresis at various strain rates

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