研究者詳細 - 増渕　雄一

論文 - 増渕　雄一

分割表示 217 件中 41 - 60 件目／全件表示 >>

Wall slip in primitive chain network simulations of shear startup of entangled polymers and its effect on the shear stress undershoot 査読有り国際共著国際誌

Yuichi Masubuchi, Dimitris Vlassopoulos, Giovanni Ianniruberto, Giuseppe Marrucci

Journal of Rheology 65 巻 ( 2 ) 頁： 213 - 223 2021年3月

Quantitative bridging between full-atomistic and bead-spring models for polybutadiene and poly(butadiene-styrene) copolymers 査読有り国際誌

Akinori Baba, Yuichi Masubuchi

Journal of Chemical Physics 154 巻 ( 4 ) 頁： 044901-1 - 044901-14 2021年1月

DNA-Chitosan Hydrogels: Formation, Properties, and Functionalization with Catalytic Nanoparticles 査読有り国際共著国際誌

Kohki Morikawa, Yuichi Masubuchi, Yury Shchipunov, Anatoly Zinchenko

ACS Applied Bio Materials 4 巻頁： 1823 - 1832 2021年

Plateau Moduli of Several Single-Chain Slip-Link and Slip-Spring Models 査読有り国際誌

Takashi Uneyama, Yuichi Masubuchi

Macromolecules 54 巻 ( 3 ) 頁： 1338 - 1353 2021年

Radial Distribution Functions of Entanglements in Primitive Chain Network Simulations 査読有り国際誌

Masubuchi Yuichi, Kida Takumitsu, Doi Yuya, Uneyama Takashi

NIHON REOROJI GAKKAISHI 49 巻 ( 5 ) 頁： 337 - 345 2021年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nihon Reoroji Gakkaishi

Although the entanglement network among polymers has been widely investigated, the spatial distribution of entanglement nodes has been rarely discussed. In this study, we obtained the radial distribution functions (RDFs) for the entanglement nodes from the snapshots of multi-chain slip-link simulations. The model employed in this study is the primitive chain network (PCN) model, which has been validated to reproduce the entangled polymer dynamics semi-quantitatively. The statistics of captured entanglement networks were compared to those reported for the primitive path network extracted by the CReTA procedure from the full-atomistic molecular model of a polyethylene melt. In the range of distance longer than the average strand length, the network structure from PCN does not show any structural correlation, and the intra-chain correlation is close to that for Gaussian chains with non-interacting slip-links. These features are consistent with the CReTA network and the conventional assumptions made for single-chain models. Meanwhile, in the short-range, the structural correlation in PCN is much weaker than that in CReTA. This discrepancy is because the short-range structure in PCN is realized as a result of imposed fluctuations, whereas it is determined by the minimization of the primitive path in CReTA.

DOI： 10.1678/rheology.49.337

Web of Science

Scopus

Primitive Chain Network Simulations of Entangled Melts of Symmetric and Asymmetric Star Polymers in Uniaxial Elongational Flows 査読有り国際共著国際誌

Masubuchi Y., Ianniruberto G., Marrucci G.

Nihon Reoroji Gakkaishi 49 巻 ( 3 ) 頁： 171 - 178 2021年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nihon Reoroji Gakkaishi

Ianniruberto and Marrucci [Macromolecules, 46, 267-275, 2013] developed a theory whereby entangled branched polymers behave like linear ones in fast elongational flows. In order to test such prediction, Huang et al [Macromolecules, 49, 6694-6699, 2016] performed elongational measurements on star polymer melts, indeed revealing that, in fast flows, the elongational viscosity is insensitive to the molecular structure, provided the molecular weight of the "backbone" (spanning the largest end-to-end distance of the molecule) is the same. Inspired by these studies, we here report on results obtained with multi-chain sliplink simulations for symmetric and asymmetric star polymer melts, as well as calculations of the Rouse time of the examined branched structures (not previously determined by Ianniruberto and Marrucci). The simulations semi-quantitatively reproduce the experimental data if the Kuhn-segment orientation-induced reduction of friction (SORF) is accounted for. The observed insensitivity of the nonlinear elongational viscosity to the molecular structure for the same span molar mass may be due to several factors. In the symmetric case, the calculated Rouse time of the star marginally differs from that of the linear molecule, so that possible differences in the observed stress fall within the experimental uncertainty. Secondly, it is possible that flow-induced formation of hooked star pairs (or even larger aggregates) makes the effective Rouse time of the aggregate even closer to that of the linear polymer because the friction center moves towards the branchpoint of the star molecule. In the asymmetric case, it is shown that the stress contributed by the short arms is negligible with respect to that of the long ones. However, such stress reduction is balanced by a dilution effect whereby the unstretched arms reduce SORF as they decrease the Kuhn-segment order parameter of the system. As a result of that dilution, the stress contributed by the backbone is larger. The two effects compensate one another, so that the overall stress is virtually the same of the other architectures.

DOI： 10.1678/rheology.49.171

Scopus

CiNii Research

Elasticity of Randomly Cross-Linked Networks in Primitive Chain Network Simulations 査読有り国際誌

Masubuchi Y.

Nihon Reoroji Gakkaishi 49 巻 ( 2 ) 頁： 73 - 78 2021年

担当区分：筆頭著者,　最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nihon Reoroji Gakkaishi

Primitive chain network simulations for randomly cross-linked slip-link networks were performed. For the percolated networks, the stress-strain relationship was compared to the theories by Ball et al. [Polymer, 22, 1010 (1981)] and Rubinstein and Panyukov [Macromolecules, 35, 6670 (2002)]. The simulation results are reasonably reproduced by both theories when the contributions from cross-links and slip-links are determined irrespective of the network structure. The fraction of slip-links contained in the network thus obtained is model dependent, and it does not coincide with the number of active slip-links in the actual networks. This discrepancy between the theories and the simulation results is due to the network inhomogeneity.

DOI： 10.1678/rheology.49.73

Scopus

CiNii Research

Linear Rheological Properties of Poly(Propylene Carbonate) with Different Molecular Weights 査読有り国際誌

Yang Lixin, Uneyama Takashi, Masubuchi Yuichi, Doi Yuya

Nihon Reoroji Gakkaishi 49 巻 ( 4 ) 頁： 267 - 274 2021年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本レオロジー学会

<p>The linear viscoelastic properties of poly(propylene carbonate) (PPC) melts having different molecular weights and narrow molecular weight distributions were studied. Some linear viscoelasticity parameters, including the plateau modulus and zero shear viscosity of PPC, were evaluated. The entanglement molecular weight of PPC was estimated to be 5.9 kg/mol, which is considerably lower than that previously reported for PPC with a broad molecular weight distribution.</p>

DOI： 10.1678/rheology.49.267

CiNii Research

Complex Network Representation of the Structure-Mechanical Property Relationships in Elastomers with Heterogeneous Connectivity 査読有り国際誌

Yoshifumi Amamoto, Ken Kojio, Atsushi Takahara, Yuichi Masubuchi, TakaakiOhnishi

Patterns 1 巻 ( 8 ) 頁： 100135-1 - 100135-9 2020年11月