Modeling the extraction of bound rubber from silica-filled styrene-butadiene rubber with toluene

田村 由起子*; 荒川 勝利*; 竹中 幹人*; 中西 洋平*; 藤波 想*; 柴田 基樹*; 山本 勝宏*; 宮田 登*; 山田 雅子*; 瀬戸 秀紀*; et al.

Polymer, 333, p.128662_1 - 128662_8, 2025/08

https://doi.org/10.1016/j.polymer.2025.128662

To investigate the relationship between the mechanical properties of silica-filled styrene-butadiene rubber (SBR) and the amount of bound rubber at the filler/rubber interface, the polymer matrix was extracted from silica-filled SBR using toluene at room temperature. In this study, this extraction process was reproduced by leaching a thermally annealed SBR layer deposited on a Si substrate in toluene at room temperature, where the adsorption layer of the SBR was grown at the interface with the substrate by thermal annealing. The SBR adsorption layer on the Si substrate has two-layer structures consisting of an inner and outer adsorption layers, which correspond to the tightly and loosely bound rubbers on the filler surface of the silica-filled SBR, respectively. For the sample annealed for less than 6 h, the outer adsorption layer, loosely bound to the substrate, was easily leached in toluene for 5 min, leaving only the inner adsorption layer on the substrate. For the samples annealed for more than 24 h, a large portion of the outer adsorption layer remained on top of the inner adsorption layer as a terrace structure. However, even for the sample annealed for 24 h, treating with toluene for 24 h completely leached the outer adsorption layer from the inner adsorption layer, although the inner adsorption layer remained on the substrate. It was found that the loosely bound rubber in the silica-filled SBR could be easily extracted from the filler surface, along with the free polymer chains in the polymer matrix during extraction with toluene at room temperature. In contrast, the tightly bound rubber was not leached by toluene at room temperature. This may be because the interfacial polymer chains within approximately 1 nm of the substrate surface were strongly constrained to the substrate, and even toluene molecules were excluded.

Adsorption isotherm and kinetics of diffusion of water accumulated between polypropylene thin film and Si substrate; Neutron reflectivity investigation

宮崎 司*; 宮田 登*; 有馬 寛*; 下北 啓輔*; 山本 勝宏*; 竹中 幹人*; 中西 洋平*; 柴田 基樹*; 青木 裕之; 山田 悟史*; et al.

Colloids and Surfaces A; Physicochemical and Engineering Aspects, 701, p.134928_1 - 134928_8, 2024/11

https://doi.org/10.1016/j.colsurfa.2024.134928

Isotactic polypropylene (PP) thin films deposited on Si substrates were subjected to neutron reflectivity (NR) measurements under various humidity conditions to evaluate the isothermal adsorption of water accumulated between the PP layer and Si substrate, with focus on the temperature-dependence of the adsorption isotherm. The adsorption of accumulated water followed a single type II isotherm according to the Brunauer-Emmett-Teller (BET) classification, regardless of temperature. This can be attributed to the weak interactions between the PP layer and Si substrate, and between the PP layer and water molecules. Hydrophobic PP does not significantly interact with water molecules and the hydrophilic Si surface. Therefore, the interfacial water molecules are simply adsorbed on the native oxide layer on Si via simple interaction between the water molecules and the silicon oxide surface without being affected by the PP layer. Consequently, the adsorption isotherm of the accumulated water follows the single type II adsorption isotherm regardless of temperature, similar to the adsorption isotherm of water simply adsorbed on exposed silica surfaces. These weak interactions of the PP layer with the Si surface and water molecules also lead to fast diffusion kinetics for the accumulated water along the interface.

Neutron reflectivity study on the adsorption layer of polyethylene grown on Si substrate

下北 啓輔*; 山本 勝宏*; 宮田 登*; 柴田 基樹*; 中西 洋平*; 荒川 勝利*; 竹中 幹人*; 木田 拓充*; 徳満 勝久*; 田中 亮*; et al.

Langmuir, 40(30), p.15758 - 15766, 2024/07

https://doi.org/10.1021/acs.langmuir.4c01584

To investigate the structure of the interface between polyethylene films and substrates, the neutron reflectivity (NR) of deuterated polyethylene (dPE) thin films deposited on Si substrates was measured, demonstrating water accumulation at the interface, even under ambient conditions. After leaching the thermally annealed dPE films in hot p-xylene, NR measurements were conducted on the layers remaining on the substrate, clearly revealing that the adsorption layer of dPE grew during annealing and consisted of two layers, an inner adsorption layer and an outer adsorption layer, as previously proposed for amorphous polymers. The inner adsorption layer was approximately 3.7 nm thick with a density comparable to that of the bulk. The outer adsorption layer was several nanometers thick and appeared to grow insufficiently on top of the inner adsorption layer under the annealing conditions examined in this study. This study clarifying the growth of the adsorption layer of polyethylene at the interface with an inorganic substrate is useful for improving the performance of polymer/inorganic filler nanocomposites due to the wide utility of crystalline polyolefins as polymer matrix materials in nanocomposites.

非破壊型静電セプタム試験機によるビーム分離実験と装置改良の検討

永山 晶大; 原田 寛之; 下川 哲司*; 佐藤 篤*; 山田 逸平; 地村 幹; 小島 邦洸; 山本 風海; 金正 倫計

Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (インターネット), p.526 - 530, 2023/11

https://www.pasj.jp/web_publish/pasj2023/proceedings/PDF/WEP1/WEP19.pdf

本研究では、ビームの遅い取り出しのための非破壊型静電セプタムを開発している。従来型と異なり、この装置はビームと衝突しないようにビーム周辺に配置した多段電極で構成されており、発生させた電場によって非破壊でビームを分離する。本研究ではその電場分布を評価すべく、電子銃とビームモニタで構成された試験装置を開発した。その装置に試作電極を設置し、細い電子ビームで電場分布測定の実験を実施した。その測定結果は計算結果との良好な一致を示した。しかし、ビームの分離能力はまだ十分ではない。そこで、電場分布の改良に向けた電極形状や配置の最適化の検討を行った。本発表では、試験装置を用いた電場分布測定実験の結果や改良案を報告する。さらに、本開発の今後の展望についても述べる。

Development of test method for evaluation of UAS mobility capability in GNSS-denied environment

山田 大地; 阿部 浩之*; 大金 一二*; 川端 邦明

ROBOMECH Journal (Internet), 10, p.13_1 - 13_8, 2023/06

https://doi.org/10.1186/s40648-023-00251-1

Unmand aircraft system (UAS)産業は将来の大きな発展が期待されている。しかし、UASによるサービスが提供される場所や場面においてUASがどの程度の性能を発揮できるかについて議論することは難しい。そこで、屋内などのGlobal Navigation Satellite System (GNSS)による測位が参照できない環境において、UASのユーザなど技術的な専門知識のない人にもUASの性能の理解が容易で、UAS間の性能の比較ができる性能評価およびその評価法を研究開発した。本研究開発では、UASメーカーやユーザーとデモやディスカッションを行い、その意見を取り入れながら評価法の改善を繰り返し実施した。また、評価法によりUASの性能の比較が可能であることを実験によって確認した。

Observation and characterization of quasi-continuous wave kW-class laser interaction with metal and metal oxide targets using a high-speed camera and microscopes

大道 博行*; 山田 知典; 猿田 晃一; 宮部 昌文; 伊藤 主税; 柴田 卓弥; 井上 薫*; 寺林 稜平*; 長谷川 秀一*

Physica Scripta, 98(3), p.035112_1 - 035112_22, 2023/02

https://doi.org/10.1088/1402-4896/acbba9

kW級の疑似連続発振レーザー(パルス時間10ms)と金属・金属酸化物との相互作用について、レーザー誘起絶縁破壊や連続的なレーザー誘起溶融・蒸発と機械的応答、それに続く様々な種類の粒子や破片の放出に関する特性評価を行った。ファイバーレーザーと高速度カメラを用いて、相互作用ダイナミクスを観察した。放出された微粒子をカスケードインパクターや自作コレクターで捕集して電子顕微鏡で観察した。照射痕形状はデジタル光学顕微鏡で観察し、ターゲットから噴出した総質量を求めた。その結果、金属との相互作用のしきい値は、酸化物との相互作用のしきい値よりも低く安定していた。またステンレス鋼では、レーザーで加熱された薄層からの熱伝導により生じる溶融層のダイナミクスと、隣接する固体層による機械的応答の少ない連続的な粒子放出が支配的であることが分った。一方、酸化物では溶融のほか、比較的深い相互作用領域での破壊と、比較的大きなレーザーショット間変動のある脆性材料応答が重要な役割を果たすらしいことが分った。

Interfacial distribution of Nafion ionomer thin films on nitrogen-modified carbon surfaces

吉宗 航*; Kikkawa, Nobuaki*; Yoneyama, Hiroaki*; Takahashi, Naoko*; Minami, Saori*; Akimoto, Yusuke*; Mitsuoka, Takuya*; Kawaura, Hiroyuki*; Harada, Masashi*; 山田 悟史*; et al.

ACS Applied Materials & Interfaces, 14(48), p.53744 - 53754, 2022/11

https://doi.org/10.1021/acsami.2c14574

Chemically modified carbon supports for the cathode catalyst layers of polymer electrolyte fuel cells (PEFCs) show considerable promise for boosting the oxygen reduction reaction. This study evaluated the ionomer distribution of Nafion ionomer thin films on nitrogen (N)-modified carbon surfaces along their depth direction. Neutron reflectivity (NR) measurements performed using the double-contrast technique with HO and DO revealed that the introduction of N functional groups to carbon thin films promoted ionomer adsorption onto the surface under wet conditions (22C, 85% relative humidity). Molecular dynamics (MD) simulations conducted to verify the origin of the robust contact between the ionomer and N-modified carbon surface revealed an ionomer adsorption mechanism on the N-modified carbon surfaces, which involved Coulomb interactions between the positively charged carbon surface and the ionomer side chains with negatively charged sulfonic acid groups. The positive surface charge, which was determined using the contents of the N functional groups estimated by X-ray photoelectron spectroscopy, was found to be sufficient as an impetus for ionomer adsorption. This strategy involving NR measurements and MD simulations can provide insights into the solid-ionomer interfacial structures in a cathode catalyst layer and can therefore be extensively employed in studies on PEFCs.

Rotation of complex ions with ninefold hydrogen coordination studied by quasielastic neutron scattering and first-principles molecular dynamics calculations

大政 義典*; 高木 茂幸*; 戸嶋 健人*; 横山 凱乙*; 遠藤 亘*; 折茂 慎一*; 齋藤 寛之*; 山田 武*; 川北 至信; 池田 一貴*; et al.

Physical Review Research (Internet), 4(3), p.033215_1 - 033215_9, 2022/09

https://doi.org/10.1103/PhysRevResearch.4.033215

Quasielastic neutron scattering (QENS) and neutron powder diffraction of the complex transition metalhydrides LiMoH and LiNbH were measured in a temperature range of 10-300 K to study their structures and dynamics, especially the dynamics of the hydrogen atoms. These hydrides contain unusual ninefold H coordinated complex ions (MoH or NbH) and hydride ions (H). A QENS signal appeared 150 K due to the relaxation of H atoms. The intermediate scattering functions derived from the QENS spectra are well fitted by a stretched exponential function called the Kohlrausch-Williams-Watts functions with a small stretching exponent 0.3-0.4, suggesting a wide relaxation time distribution. The dependence of the elastic incoherent structure factor is reproduced by the rotational diffusion of MH (M = Mo or Nb) anions. The results are well supported by a van Hove analysis for the motion of H atoms obtained using first-principles molecular dynamics calculations. We conclude that the wide relaxation time distribution of the MH rotation is due to the positional disorder of the surrounding Li ions and a unique rotation with MH anion deformation (pseudorotation).

原子力災害対応用ロボットの性能試験法; ロボットアームによる障害物の乗り越えを介した接近試験(JAEA-TM-0006)

山田 大地; 川端 邦明; 阿部 浩之*

JAEA-Technology 2021-033, 18 Pages, 2022/03

JAEA-Technology-2021-033.pdf:1.58MB

本稿は、原子力災害対応および廃炉作業に用いるロボット等の遠隔操作機器(以下、ロボット)の性能を定量的に評価するとともに、その性能を比較するための試験法について記述したものである。東京電力ホールディングス株式会社福島第一原子力発電所での事故発生後、多くの遠隔操作ロボットが作業に活用されている。災害は発生件数が少ないため、実際の事故対応の作業経験と教訓は、将来の遠隔操作ロボットの開発において重要となる。そこで、我々は福島第一原子力発電所での遠隔操作ロボットによる作業を参考にしてロボット性能評価のための試験方法の開発に取り組んでいる。福島第一原子力発電所の事故対応では、ロボットアームを備えたロボットがロボットアームにより作業対象への接触や作業対象の移動、作業対象を撮影するタスクがあった。また、それらの中には、壁などの障害物により作業対象までの直線的なアクセスを物理的、視覚的に遮られるため、ロボットアームにより障害物の上方を越えて作業対象に接近、接触するタスクがあった。本稿は、壁状の障害物の上方または障害物の奥にある作業対象への接近に関する性能を定量的に評価するための試験手順について記述するものである。試験実施の参考のために、具体的な試験環境の例とテスト実行のデモンストレーションの様子についても掲載している。

Multilayered lamellar materials and thin films by instant self-assembly of amphiphilic random copolymers

Ikami, Takaya*; Watanabe, Yuki*; 小川 紘輝*; 竹中 幹人*; 山田 悟史*; 大内 誠*; 青木 裕之; 寺島 崇矢*

ACS Macro Letters (Internet), 10(12), p.1524 - 1528, 2021/12

https://doi.org/10.1021/acsmacrolett.1c00571

Making ordered nanostructures in polymers and their thin films is an important technique to produce functional materials. Herein, we report instant yet precise self-assembly systems of amphiphilic random copolymers to build multilayered lamellar structures in bulk materials and thin films. Random copolymers bearing octadecyl groups and hydroxyethyl groups induced crystallization-driven microphase separation via simple evaporation from the solutions to form lamellar structures in the solid state. The domain spacing was controlled in the range between 3.1 and 4.2 nm at the 0.1 nm level by tuning copolymer composition. Interestingly, just by spin-coating the polymer solutions onto silicon substrates, the copolymers autonomously formed thin films consisting of multilayered lamellar structures, where amorphous/hydrophilic parts and crystalline octadecyl domains are alternatingly layered from a silicon substrate to the air/polymer interface at regular intervals. The lamellar domain spacing was tunable by selecting hydrophilic pendants.