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

Tamura, Yukiko*; Arakawa, Masato*; Takenaka, Mikihito*; Nakanishi, Yohei*; Fujinami, So*; Shibata, Motoki*; Yamamoto, Katsuhiro*; Miyata, Noboru*; Yamada, Masako*; Seto, Hideki*; et al.

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

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

Fluorous and organic extraction systems; A Comparison from the perspectives of coordination structures, interfaces, and bulk extraction phases

Ueda, Yuki; Micheau, C.; Akutsu, Kazuhiro*; Tokunaga, Kohei; Yamada, Masako*; Yamada, Norifumi*; Bourgeois, D.*; Motokawa, Ryuhei

Langmuir, 40(46), p.24257 - 24271, 2024/11

https://doi.org/10.1021/acs.langmuir.4c02268

Microscopic structures in liquid-liquid extraction, such as structuration between extractants or extracted complexes in bulk organic phases and at interfaces, can influence macroscopic phenomena, such as the distribution behavior of solutes, including extraction efficiency, selectivity, and phase separation of the organic phase. In this study, we correlated the macroscopic behavior of the extraction of Zr(IV) ions from nitric acid solutions with microscopic structural information in order to understand at the molecular level the key factors contributing to the higher metal ion extraction performance in the fluorous extraction system comprising fluorous phosphate (TFP) in perfluorohexane as compared to the analogous organic extraction system comprising organic phosphate (THP) in n-hexane. Extended X-ray absorption fine structure, neutron reflectometry, and small-angle neutron scattering revealed the local coordination structure around the Zr(IV) ion, the accumulation of extractant molecules at the interface, and the structuration of extractant molecules in the bulk extraction phase, respectively. In the fluorous extraction system, extractant aggregates with were formed after contact with nitric acid. In contrast, in the organic extraction system, only extractant dimers were formed. We speculate that differences in the local coordination structure around the Zr(IV) ion and the structuration of the extractant molecules in the bulk extraction phase contribute to the high Zr(IV) extraction performance in the fluorous extraction system. In particular, the size of the aggregates hardly changed with increasing Zr(IV) concentration in the fluorous phase, which may be closely related to the absence of phase splitting in the fluorous extraction system.

Organization of malonamides from the interface to the organic bulk phase

Micheau, C.; Ueda, Yuki; Motokawa, Ryuhei; Akutsu, Kazuhiro*; Yamada, Norifumi*; Yamada, Masako*; Moussaoui, S. A.*; Makombe, E.*; Meyer, D.*; Berthon, L.*; et al.

Journal of Molecular Liquids, 401, p.124372_1 - 124372_12, 2024/05

https://doi.org/10.1016/j.molliq.2024.124372

Nanometer-scale water droplet free from the constraint of reverse micelles at low temperatures

Murakami, Hiroshi; Sada, Tomoko*; Yamada, Masako*; Harada, Masafumi*

Physical Review E, 88(5), p.052304_1 - 052304_8, 2013/11

https://doi.org/10.1103/PhysRevE.88.052304

no abstracts in English

Neutron mirror with magnetic repulsive wall

Fuwa, Yasuhiro; Kuriyama, Yasutoshi*; Iwashita, Yoshihisa*; Hirota, Katsuya*; Yamada, Masako*; Kitaguchi, Masaaki*; Shimizu, Hirohiko*

no journal, , 

A neutron mirror with a magnetic repulsive wall is under development. Since neutrons have a magnetic dipole moment, they are subject to forces in a magnetic field gradient. Using this phenomenon, a potential wall for neutrons can be formed by arranging permanent magnets in a planar configuration of a Halbach array. This potential wall acts as a mirror for a polarized neutron beam. A prototype mirror 20 mm high and 30 mm wide was fabricated, and preliminary neutron reflection experiments were conducted at the MINE2 port of JRR-3. As the next step, we plan to fabricate a mirror with a larger size and conduct experiments at the J-PARC MLF. In this presentation, the principle of the mirror, the results of preliminary experiments at JRR-3, and the status of the mirror fabrication for the experiment at J-PARC will be reported.

Temperature dependence of fluctuation of water in a nanometer-confined space

Murakami, Hiroshi; Sada, Tomoko; Yamada, Masako*; Harada, Masafumi*

no journal, , 

no abstracts in English

Neutron beam manipulation utilizing spin magnetic dipole moment

Fuwa, Yasuhiro; Iwashita, Yoshihisa*; Kuriyama, Yasutoshi*; Yamada, Masako*; Hirota, Katsuya*; Kitaguchi, Masaaki*; Shimizu, Hirohiko*

no journal, , 

Since neutrons have a spin magnetic moment, they are subject to a force due to their interaction with the magnetic field gradient. The direction of this force coincides with the direction of the magnetic field gradient vector, and the force acts in the opposite direction depending on the direction of the spin. By utilizing this force, the neutron beam can be manipulated. If the magnetic field gradient is transverse to the beam axis, the beam is deflected. Therefore, if a sextupole magnet is used to generate a magnetic field, the magnetic field gradient changes in proportion to the distance from the center of the beam axis, which causes the same effect as a lens, and the neutron beam can be focused. In addition, by arranging permanent magnets in a Halbach array on a plane and generating a uniform magnetic field gradient in the direction normal to the plane, a neutron beam reflecting wall can be formed, which can be combined in a duct-like configuration to form a guide tube. The magnetic field gradient in the longitudinal direction relative to the beam axis can change the energy of the neutrons. The integral value of this energy change is zero if the neutrons just pass through, but if the spins are flipped in the magnetic field gradient, the neutron beam can be accelerated or decelerated with the energy corresponding to the magnetic flux density at the flipped location. By applying this technique, spatial focusing and energy modulation of neutron beams are possible. In this presentation, the principle and configuration of the instruments we are developing for neutron beam manipulation and the planned experiments are described, and their potential applications are discussed.

Extraction mechanisms in fluorous and organic extraction systems and structuring extractants in bulk extraction phases

Ueda, Yuki; Micheau, C.; Akutsu-Suyama, Kazuhiro*; Tokunaga, Kohei; Yamada, Masako*; Yamada, Norifumi*; Bourgeois, D.*; Motokawa, Ryuhei

no journal, , 

no abstracts in English

Temperature dependence of fluctuation of water in a nanometer-confined space

Murakami, Hiroshi; Sada, Tomoko; Yamada, Masako*; Harada, Masafumi*

no journal, , 

no abstracts in English