TY - JOUR

T1 - Dynamic viscoelastic properties of dilute pullulan ionic liquids solutions

AU - Hao, Hu

AU - Takahashi, Yoshiaki

PY - 2017

Y1 - 2017

N2 - Dynamic viscoelastic properties of standard pullulan samples with different molecular weights and narrow molecular weight distributions in ionic liquids are measured in non-entangled region over a wide range of chain overlapping (1 ≤ C [η ] ≤ 12.6) and compared with Rouse-Zimm (RZ) theory with and without introducing correction term called long time (LT) term, proposed by Osaki et al. (J. Polym. Sci., Part B, Polym. Phys. Ed., 39, 211-217, (2001)). When chains are overlapped (say 2.5 ≤ C [η ]), loss modulus data (G" ) can be well expressed by the RZ theory with experimentally determined longest relaxation time τRZ while storage modulus (G' ) was larger than the calculation. However, addition of LT term made reasonable correction for calculation of G' similar to the results for standard polystyrenes. To apply the RZ fitting for Mw estimation of unknown sample (fitting G" by RZ theory), estimation error for τRZ and resulting Mw are examined. At high C [η ], relative error of estimated Mw was about 15%, as long as t RZ can be determined with small error and coincidence of τ RZ and the longest Rouse relaxation time calculated from estimated Mw is confirmed. At lower C [η ], this method tend to underestimate Mw and the error become larger.

AB - Dynamic viscoelastic properties of standard pullulan samples with different molecular weights and narrow molecular weight distributions in ionic liquids are measured in non-entangled region over a wide range of chain overlapping (1 ≤ C [η ] ≤ 12.6) and compared with Rouse-Zimm (RZ) theory with and without introducing correction term called long time (LT) term, proposed by Osaki et al. (J. Polym. Sci., Part B, Polym. Phys. Ed., 39, 211-217, (2001)). When chains are overlapped (say 2.5 ≤ C [η ]), loss modulus data (G" ) can be well expressed by the RZ theory with experimentally determined longest relaxation time τRZ while storage modulus (G' ) was larger than the calculation. However, addition of LT term made reasonable correction for calculation of G' similar to the results for standard polystyrenes. To apply the RZ fitting for Mw estimation of unknown sample (fitting G" by RZ theory), estimation error for τRZ and resulting Mw are examined. At high C [η ], relative error of estimated Mw was about 15%, as long as t RZ can be determined with small error and coincidence of τ RZ and the longest Rouse relaxation time calculated from estimated Mw is confirmed. At lower C [η ], this method tend to underestimate Mw and the error become larger.

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U2 - 10.1678/rheology.45.133

DO - 10.1678/rheology.45.133

M3 - Article

AN - SCOPUS:85027558945

VL - 45

SP - 133

EP - 138

JO - Nihon Reoroji Gakkaishi

JF - Nihon Reoroji Gakkaishi

SN - 0387-1533

IS - 3

ER -