Faculty Profiles - UNEYAMA Takashi

Papers - UNEYAMA Takashi

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Rheological properties of linear and short-chain branched polyethylene with nearly monodispersed molecular weight distribution Reviewed

Kida T., Doi Y., Tanaka R., Uneyama T., Shiono T., Masubuchi Y.

Rheologica Acta Vol. 60 ( 9 ) page： 511 - 519 2021.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Rheologica Acta

We synthesized model polyethylene (PE) samples with nearly monodispersed molecular weight distribution and different fractions of short-chain branches to investigate the influences of the branch structure on the rheological properties. The activation energy of the flow process showed linear relations with the weight fractions of comonomer and the short-chain branch. These results suggest that the friction of the chain motion is dominated by the amount of the short-chain branch. The zero-shear viscosity showed a power law to Mw with an exponent of about 3.3 for all linear and branched PEs. The branched PEs showed large entanglement molecular weights compared with the linear PEs because the introduction of the short-chain branches results in the increase of the average molecular weight per backbone unit. Moreover, the introduction of the short-chain branches has no influence on the strain-hardening under an extensional elongation process, indicating that the short-chain branches only affect the friction.

DOI： 10.1007/s00397-021-01286-0

Scopus

Linear Viscoelasticity of Dumbbells Interacting via Gaussian Soft-Core Potential Reviewed

Takashi Uneyama

Nihon Reoroji Gakkaishi Vol. 49 ( 2 ) page： 61 - 71 2021.4

Plateau Moduli of Several Single-Chain Slip-Link and Slip-Spring Models Reviewed

Takashi Uneyama and Yuichi Masubuchi

Macromolecules Vol. 54 ( 3 ) page： 1338-1353 2021.1

Short-time dynamics of a tracer in an ideal gas Reviewed

Nakai Fumiaki, Masubuchi Yuichi, Uneyama Takashi

PHYSICAL REVIEW E Vol. 102 ( 3 ) 2020.9

からみあった高分子のメソスケールモデリングの進展 Invited

畝山多加志

分子シミュレーション学会誌 "アンサンブル" Vol. 22 ( 3 ) page： 210-215 2020.7

Primitive chain network simulations for the interrupted shear response of entangled polymeric liquids. Reviewed

Masubuchi Y, Doi Y, Uneyama T

Soft matter Vol. 16 ( 28 ) page： 6654-6661 2020.7

ゆらぐ拡散係数を用いた拡散・緩和現象の記述 Invited

畝山多加志

分子シミュレーション学会誌 "アンサンブル" Vol. 22 ( 2 ) page： 134-141 2020.4

Dissipation in Langevin equation and construction of mobility tensor from dissipative heat flow Reviewed

Uneyama T.

Nihon Reoroji Gakkaishi Vol. 48 ( 2 ) page： 65-78 2020.4

Coarse-graining of microscopic dynamics into a mesoscopic transient potential model Reviewed

Uneyama Takashi

PHYSICAL REVIEW E Vol. 101 ( 3 ) 2020.3

Entanglement Molecular Weight Reviewed

MASUBUCHI Yuichi, DOI Yuya, UNEYAMA Takashi

Nihon Reoroji Gakkaishi Vol. 48 ( 4 ) page： 177-183 2020

高分子の粗視化モデリングとシミュレーション Invited

畝山多加志

日本化学会情報化学部会誌 Vol. 37 ( 4 ) page： 81-86 2019.12

Multi-chain slip-spring simulations for polyisoprene melts Reviewed

Masubuchi Y. and Uneyama T.

Korea Australia Rheology Journal Vol. 31 ( 4 ) page： 241-248 2019.11

Role of Chain Ends in Dynamics of Entangled Polymers Invited

Vol. 68 page： 598-600 2019.10

Effect of Inertia on Linear Viscoelasticity of Harmonic Dumbbell Model Reviewed

Takashi Uneyama, Fumiaki Nakai, and Yuichi Masubuchi

Nihon Reoroji Gakkaishi (J. Soc. Rheol. Jpn.) Vol. 47 ( 4 ) page： 143-154 2019.9

Unveiling diffusive states from center-of-mass trajectories in glassy dynamics. Reviewed

Hachiya Y, Uneyama T, Kaneko T, Akimoto T

The Journal of chemical physics Vol. 151 ( 3 ) page： 034502 2019.7

Brownian motion with alternately fluctuating diffusivity: Stretched-exponential and power-law relaxation Reviewed

Tomoshige Miyaguchi, Takashi Uneyama, and Takuma Akimoto

Physical Review E Vol. 100 ( 1 ) page： 012116 2019.7

Retardation of the reaction kinetics of polymers due to entanglement in the post-gel stage in multi-chain slip-spring simulations. Reviewed

Masubuchi Y, Uneyama T

Soft matter Vol. 15 ( 25 ) page： 5109-5115 2019.6

Relaxation functions of the Ornstein-Uhlenbeck process with fluctuating diffusivity Reviewed

Takashi Uneyama, Tomoshige Miyaguchi, and Takuma Akimoto

Physical Review E Vol. 99 ( 3 ) page： 032127 2019.3

Characterization of critical gel state of polyamides by viscoelastic, thermal, and IR measurements Reviewed

T. Hirayama, T. Uneyama, and Y. Masubuchi

Rheologica Acta Vol. 58 ( 5 ) page： 281-290 2019.3

A Self-Consistent Field Theory Based on a Soft-Dumbbell Model for Symmetric Diblock Copolymers Reviewed

UNEYAMA Takashi

KOBUNSHI RONBUNSHU Vol. 76 ( 1 ) page： 44-51 2019.1

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

<p>We propose a highly coarse-grained, self-consistent field (SCF) theory for simulations of symmetric diblock copolymers, based on the soft dumbbell model. We apply the standard derivation method of the SCF model to the soft dumbbell model, and derive the set of self-consistent equations. We perform the SCF simulations in one dimension, based on the derived model, and show that the SCF model can reproduce microphase separation structures properly. We theoretically consider the properties of the model and discuss possible applications.</p>

DOI： 10.1295/koron.2018-0035

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Papers - UNEYAMA Takashi