Rheological Behavior of Weakly Associated Polymers

Urakawa, Osamu; Ikuta, Hiroyoshi; Maji, Satoshi; Inoue, Tadashi

doi:10.1678/rheology.46.131

Cited by 3 publications

(2 citation statements)

References 26 publications

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“…Based on this assumption, we superposed the WLF curve fitted to the

data onto the other data through the horizontal and vertical shifts. The detail of this method has been reported previously [ 41 ]. The fit results are shown by the solid lines in Figure 9 a, demonstrating that a single WLF parameter set can approximately represent all the data.…”

Section: Resultsmentioning

confidence: 99%

Viscoelastic Relaxation of Polymerized Ionic Liquid and Lithium Salt Mixtures: Effect of Salt Concentration

et al. 2021

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Polymerized ionic liquids (PILs) doped with lithium salts have recently attracted research interests as the polymer component in lithium-ion batteries because of their high ionic mobilities and lithium-ion transference numbers. To date, although the ion transport mechanism in lithium-doped PILs has been considerably studied, the role of lithium salts on the dynamics of PIL chains remains poorly understood. Herein, we examine the thermal and rheological behaviors of the mixture of poly(1-butyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide (PC4-TFSI)/lithium TFSI (LiTFSI) in order to clarify the effect of the addition of LiTFSI. We show that the glass transition temperature Tg and the entanglement density decrease with the increase in LiTFSI concentration wLiTFSI. These results indicate that LiTFSI acts as a plasticizer for PC4-TFSI. Comparison of the frequency dependence of the complex modulus under the iso-frictional condition reveals that the addition of LiTFSI does not modify the stress relaxation mechanism of PC4-TFSI, including its characteristic time scale. This suggests that the doped LiTFSI, component that can be carrier ions, is not so firmly bound to the polymer chain as it modifies the chain dynamics. In addition, a broadening of the loss modulus spectrum in the glass region occurs at high wLiTFSI. This change in the spectrum can be caused by the responses of free TFSI and/or coordination complexes of Li and TFSI. Our detailed rheological analysis can extract the information of the dynamical features for PIL/salt mixtures and may provide helpful knowledge for the control of mechanical properties and ion mobilities in PILs.

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“…Based on this assumption, we superposed the WLF curve fitted to the

Section: Resultsmentioning

confidence: 99%

Viscoelastic Relaxation of Polymerized Ionic Liquid and Lithium Salt Mixtures: Effect of Salt Concentration

et al. 2021

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“…data onto the other data through the horizontal and vertical shifts. The precise method has been reported previously 34) .…”

Section: Viscoelastic Spectra Of 2vpy/vph Blendsmentioning

confidence: 99%

Rheological Behavior of Hydrogen Bonding Miscible Blend: High Molecular Weight Poly(2-vinyl pyridine) and Low Molecular Weight Poly(4-vinyl phenol)

Urakawa

Yasue

Inoue

2021

J. Soc. Rheol., Jpn

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We examined thermal and rheological behaviors for miscible polymer blends, poly(2-vinyl pyridine) / poly(4-vinyl phenol) (2VPy/VPh), in which intermolecular hydrogen bonds play an important role. The molecular weights of the 2VPy and VPh components are higher and lower than the critical sizes of the entanglement, respectively. In the mixture of these two polymers, only the 2VPy chains entangle each other, and the low molecular weight VPh is expected to act as a diluent. We found that the time-temperature superposition principle approximately held. The Williams-Landel-Ferry equation with a single parameter set (C 1 and C 2 ) could represent their shift factors by setting the reference temperatures to be T g + 64 ºC. From the comparison of the composite curves, we found that the intermolecular hydrogen bonds did not affect the entanglement densities but made the zero shear viscosities larger and the relaxation times longer.

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Relaxation modes of metaphosphate glasses with entropic shrinkage

Yaoita¹,

Inaba²

2021

AIP Advances

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We have reconfirmed the anomalistic reversible strain (shrinkage) after tensile creep in the specific metaphosphate glass melts with entropic elasticity in a wide range of applied stresses. We attempted to elucidate the origin of the anomalistic shrinkage by focusing on the relaxation modes. The fast mode was identified for all glasses by two different measurements, i.e., the dynamic viscoelasticity in the linear range and the creep recovery in the non-linear range. In contrast, the slow mode in addition to the fast mode was confirmed only for the glasses showing the anomalistic shrinkage. The slow mode induced the essential shrinkage at whole tensile stresses, whereas the fast mode, especially at higher tensile stresses, contributed to the moderate shrinkage. As the most likely mechanism in the linear range, the local segmental motion with mobile cation motion and the large-scale relaxation of the connected molecules through scission and renewal of the bond between alkali cations and the oxygen anion were assigned to the fast and the slow modes, respectively. In the non-linear range, the dimensionless strain-rate dependence of the reversible strains for both modes had a similar characteristic to that of the viscosity.

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Rheological Behavior of Weakly Associated Polymers

Cited by 3 publications

References 26 publications

Viscoelastic Relaxation of Polymerized Ionic Liquid and Lithium Salt Mixtures: Effect of Salt Concentration

Viscoelastic Relaxation of Polymerized Ionic Liquid and Lithium Salt Mixtures: Effect of Salt Concentration

Rheological Behavior of Hydrogen Bonding Miscible Blend: High Molecular Weight Poly(2-vinyl pyridine) and Low Molecular Weight Poly(4-vinyl phenol)

Relaxation modes of metaphosphate glasses with entropic shrinkage

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