Faculty Profiles - KAWASUMI Masaya

Single-Walled Carbon Nanotubes Supported Pt Electrocatalyst as a Cathode Catalyst of a Single Fuel Cell with High Durability against Start-up/Shut-down Potential Cycling

Huda, M; Kawahara, T; Park, JH; Kawasumi, M; Matsuo, Y

ACS APPLIED ENERGY MATERIALS Vol. 6 ( 24 ) page： 12226 - 12236 2023.12

Language：English Publishing type：Research paper (scientific journal) Publisher：ACS Applied Energy Materials

Carbon nanotubes (CNTs) have remarkable properties such as high conductivity, high porosity, and high oxidation resistance, which make them excellent candidates for supporting electrocatalysts in proton exchange membrane fuel cells (PEMFCs). In this study, high-crystallinity, high-purity single-walled carbon nanotubes (SWCNTs), which were prepared by enhanced direct injection pyrolytic synthesis (e-DIPS), were used as a support for a metal electrocatalyst. Platinum (Pt) nanoparticles of uniform size were synthesized by a facile solvothermal method and distributed evenly on the surface of the SWCNTs (Pt/SWCNT). Electrochemical measurements using cyclic voltammetry and linear sweep voltammetry showed that the Pt/SWCNT exhibited higher mass activity and specific activity compared to commercial Pt nanoparticles supported on graphitized carbon (Pt/C). A PEMFC membrane electrode assembly (MEA) utilizing Pt/SWCNT as the cathode layer (Pt/SWCNT-MEA) with low Pt loading demonstrated high-efficiency performance with power density per gram of Pt that was three times higher than that of Pt/C. Furthermore, in a durability test using a high-voltage triangular wave between 1.0 and 1.5 V to induce corrosion of the catalyst and carbon support, simulating harsh conditions of actual repeated start-up/shut-down cycles during long-term use, the Pt/SWCNT-MEA retained high performance even after 10,000 potential cycles. These results indicate that SWCNTs show promise as an excellent support material for electrocatalysts, offering high performance and durability, and thus can contribute to realizing PEMFCs with superior performance.

DOI： 10.1021/acsaem.3c01919

Highly durable graphene-encapsulated platinum-based electrocatalyst for oxygen reduction reactions synthesized by solution plasma process

Park, JH; Kim, K; Wang, XY; Huda, M; Sawada, Y; Matsuo, Y; Saito, N; Kawasumi, M

JOURNAL OF POWER SOURCES Vol. 580 2023.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Power Sources

Though expensive platinum (Pt) is used as catalyst for oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs), insufficient durability remains as a bottleneck for commercialization of PEFCs. Improving both catalytic performance and durability by graphene encapsulation is an attractive strategy to solve this problem. In this study, graphene-encapsulated PtFe core-shell catalyst is synthesized with dimethyl formamide (DMF) and a pair of Pt and Fe electrodes without using any metal salts by utilizing the solution plasma (SP) process. TEM and EELS results show synthesized PtFe nanoparticles are encapsulated with close to single-layered highly crystallized graphene. Although commercial Pt/C showed significant performance degradation (ECSA −33%, MA −68%) after 50,000 cycles of accelerated durability test (ADT), PtFe core-shell catalyst shows remarkably improved durability (ECSA −13%, MA −19%) while graphene shell clearly remains. The improved durability is more prominent in the single cell test, the decrease in maximum power density after 6000 cycles of ADT was significantly lower as −1.2%, compared to that of Pt/C (−52.1%). This study introduces a novel and attractive catalyst synthesis process by the SP method followed by heat treatments and suggests graphene encapsulation can improve long-term durability of catalyst while maintaining ORR activity.

DOI： 10.1016/j.jpowsour.2023.233419

Novel solution plasma synthesis of highly durable carbon shell encapsulated platinum-based cathode catalyst for polymer electrolyte membrane fuel cells

Park, JH; Saito, N; Kawasumi, M

CARBON Vol. 214 2023.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Carbon

Developing an effective method for synthesizing high-performance and durable catalysts for the oxygen reduction reaction is of great importance for cost reduction and the wide application of fuel cells. This study presents a simple and effective strategy using a plasma reaction in the liquid phase to synthesize carbon-shell-encapsulated Pt and PtFe catalysts. A carbon-shell-encapsulated PtFe catalyst alloyed with up to 29 at.% Fe exhibits a mass activity of 730 mA·mgpt−1 and a specific activity of 1772 μA cm−1, which are 2.4 and 5 times higher than that of commercial Pt/C, respectively. The carbon shell effectively maintained the low oxidation state of Pt by suppressing the formation of Pt–OH and significantly improved the durability of the catalyst in accelerated durability tests, increasing the gap in mass activity with Pt/C by a factor of up to six after 50,000 cycles. In addition, the decrease in the electrochemical surface area by the carbon shell enabled a more stable 4-electron reaction over a wide potential range. This study may provide fascinating insights into the effect of the carbon shell contributing to the improvement of the catalytic activity and durability of fuel cells as well as the novel plasma-based synthesis strategy of core-shell catalyst.

DOI： 10.1016/j.carbon.2023.118364

Efficient CO2/Electrochemical Reduction by a Robust Electrocatalyst Fabricated by Electrodeposition of Indium and Zinc over Copper Foam

Sirisomboonchai, S; Machida, H; Tran, KVB; Kawasumi, M; Norinaga, K

ACS APPLIED ENERGY MATERIALS Vol. 5 ( 8 ) page： 9846 - 9857 2022.8

Language：English Publishing type：Research paper (scientific journal) Publisher：ACS Applied Energy Materials

Electrochemical reduction of CO2comprising the CO2reduction reactuib (CO2RR) and oxygen evolution reaction (OER) is one of the most promising technologies for electrification of the chemical process industry. Here, the performance of a electrocatalyst with a three-dimensional structure of InZnCu on Cu foam (CF) is presented. This electrocatalyst was fabricated by electrodeposition of In and Zn over Cu and exhibited a superior reduction of CO2to CO at a Faradaic efficiency of 93.7% at -0.7 V and an excellently long duration of 100 h. Due to the synergy of the thin In layer, the Zn nanosheets provided a high surface-active area and strong mechanical robustness during the reaction. Additionally, a two-electrode system was constructed based on the CF-modified surface, which provided valuable guidelines on the overall CO2RR-OER system for further evolution. Furthermore, due to the facile synthesis, the bimetal-layer double hydroxide (LDH) exhibited high conductivity and high OER performance. Hence, the two-electrode system assembled excellent electrocatalysts for the CO2RR-OER (InZnCu/CF||Cu(OH)2NWs@NiCo-LDH/CF) with high conversions of CO2to CO of 67% and 88% at 2 and 50 mA cm-2, respectively. Notably, the CO2RR-OER system exhibited excellent stability in a 40 h CO2conversion with a constant current density of 2 mA cm-2at an ultralow voltage of 1.59 V. Moreover, the calculation of the energy input converting CO per ton of CO2resulted in a low energy input range for further development in scalability. This overall CO2RR-OER proposes development in electrochemical CO2reduction for industrial applications.

DOI： 10.1021/acsaem.2c01564

Non-crosslinked perfluoro-polymer electrolytes with two acid groups and their properties

Synthesis and Properties of Fluorocarbon–Hydrocarbon Hybrid Block Copolymers with Perfluorosulfonimide Acid Reviewed

Vol. 5 ( 43 ) page： 27766 - 27773 2020.10

Nanocomposites Based on Organic and Inorganic Materials and Their unique Properties and Functions

Masaya Kawsasumi

R&D Review of Toyota CRDL Vol. 50 ( 2 ) page： 45 - 61 2019

Properties of a Novel Imide Network Polymer Electrolyte and Fuel Cell Performance of Its Composite Membrane

Kyoko Tsusaka, Naoki Kitano, Takashi Yamamoto, Naoki Hasegawa, Akihiko Koiwai, Masaya Kawasumi

R&D Review of Toyota CRDL Vol. 49 ( 4 ) page： 21 - 31 2018

Imide Crosslinked Perfluorinated Proton Exchange Membranes by Gas Treatment

Tsusaka Kyoko, Yamamoto Takashi, Asano Takashi, Muto Atsuko, Hasegawa Naoki, Kawasumi Masaya

JOURNAL OF THE ELECTROCHEMICAL SOCIETY Vol. 163 ( 5 ) page： F372 - F376 2016

スルホン酸修飾メソポーラスシリカ(乾燥状態)のプロトンダイナミクス

蒲沢和也, 藤田悟, 荒木暢, 長谷川直樹, 川角昌弥, Madhusudan Tyagi, 杉山純

日本物理学会講演概要集 Vol. 69.2.4 2014.8

Ion Conductive Organic-inorganic Hybrid Electrolyte with Meso-scale Proton Channels for Fuel Cells

Satoru Fujita, Kazuya Kamazawa, Satoru Yamamoto, Akihiko Koiwai, Shinji Inagaki, Jun Sugiyama, Masaya Kawasumi

R&D Review of Toyota CRDL Vol. 44 ( 4 ) page： 59 - 69 2014

Akihiro Shinohara, Kenji Kudo, Masaya Kawasumi, Yu Morimoto, Naoki Hasegawa

ECS Transactions Vol. 58 ( 1 ) page： 253 - 259 2013.8

Enhancement of Proton Transport by High Densification of Sulfonic Acid Groups in Highly Ordered Mesoporous Silica

Fujita Satoru, Koiwai Akihiko, Kawasumi Masaya, Inagaki Shinji

CHEMISTRY OF MATERIALS Vol. 25 ( 9 ) page： 1584 - 1591 2013.5

Proton conductivity under dry conditions for mesoporous silica with highly dense sulfonic acid groups

Fujita S., Kamazawa K., Yamamoto S., Tyagi M., Araki T., Sugiyama J., Hasegawa N., Kawasumi M.

Journal of Physical Chemistry C Vol. 117 ( 17 ) page： 8727 - 8736 2013.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Physical Chemistry C

Highly dense sulfonic acid-functionalized mesoporous electrolytes with high proton conductivity under dry conditions were prepared using tetramethoxysilane and 3-mercaptopropyltrimethoxysilane in the presence of surfactants. Impedance spectroscopy and quasielastic neutron scattering measurements showed that the proton conductive properties of the mesoporous electrolytes depended significantly on the sulfonic acid densities on the surface of the mesoporous walls. This finding was also supported by molecular dynamics simulations. The proton conductivity of the mesoporous electrolyte with the highest acid density of 3.1 SO3H molecules/nm2 showed a value of 0.3 mS/cm at 433 K even under dry conditions. This value was higher than that for Nafion by about 2 orders of magnitude. Such high proton conductivity is thought to be induced by proton hopping in the hydrogen-bonded networks that were predominantly formed by neighboring sulfonic acid groups. © 2013 American Chemical Society.

DOI： 10.1021/jp307058s

Development and applications of polyolefin- and rubber-clay nanocomposites

Kato M., Usuki A., Hasegawa N., Okamoto H., Kawasumi M.

Polymer Journal Vol. 43 ( 7 ) page： 583 - 593 2011.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Polymer Journal

A nylon 6-clay hybrid (nanocomposite, NCH) was developed by Toyota CRDL group. In the NCH, the silicate layers of clay mineral are dispersed on a nanometer level and are strongly interacted with the matrix, and then significant improvements in the mechanical properties of the material or the discovery of unexpected new properties were realized. Polypropylene (PP) is the most widely used polymer, and then an appearance of a PP-clay nanocomposite has been desired for a long time. As a PP does not include any polar groups in its backbone, it was thought that the homogeneous dispersion of the silicate layers would not be realized. But we have developed successfully PP-clay nanocomposite using organoclay and modified PP. That is, organophilic clay, PP oligomer carrying polar groups and PP were melt-blended. This is a direct polymer intercalation process for preparing polymer nanocomposites by melt compounding, a useful process from an industrial standpoint. We have also developed successfully other polyolefin polymers (polyethylene), polyolefin rubbers (ethylene-propylene elastomer, ethylene-propylene diene monomer) and nanocomposites by this direct polymer intercalation process or by techniques based on direct polymer intercalation process. These prepared polyolefin nanocomposites exhibit superior mechanical, thermal and gas barrier properties. © The Society of Polymer Science, Japan (SPSJ) All rights reserved.

DOI： 10.1038/pj.2011.44

Angular distribution of elemental composition of films deposited by laser ablation of a SrZrO3 target

フッ素・炭化水素ブロック共重合電解質膜の合成と評価

星川尚弘，篠原朗大，細川洋一，長谷川直樹，川角昌弥

高分子学会予稿集 page： 4686 - 4686 2010

Konomi I., Motohiro T., Horii M., Kawasumi M.

Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films Vol. 26 ( 6 ) page： 1455 - 1461 2008.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films

The angular distributions of elemental composition of films prepared by laser ablation of perovskite oxide SrZrO3 have been investigated using electron probe microanalysis with wavelength-dispersive spectroscopy. Each constituent element showed two modal distribution composed of a broad cos m θ (m=2-3) distribution and a sharp cosn θ (n=8-23) distribution. Oxygen showed a broader distribution than that of Sr and Zr. At the polar angle close to surface normal direction (polar angle <12°), Zr concentration was higher than that of Sr in vacuum whereas in oxygen-containing atmosphere their concentrations were about the same. Below oxygen pressure of 1.3 Pa, Sr and Zr concentration increased and decreased with the increase in polar angle, respectively, whereas in oxygen partial pressure of 10 Pa, both elements showed no angular dependences. Broadening of angular distribution of all the elements was observed when deposition was performed under oxygen partial pressure of 10 Pa, which is considered to be caused by collisional scatterings of more than ten times with ambient gas molecules. © 2008 American Vacuum Society.

DOI： 10.1116/1.2987952

Degradation of Perfluorinated Membranes Having Intentionally Formed Pt-Band

Electrode and Membrane Durability Issues of PEFCs

Hatanaka Tatsuya, Takeshita Tomohiro, Murata Hajime, Hasegawa Naoki, Asano Takashi, Kawasumi Masaya, Morimoto Yu

PROTON EXCHANGE MEMBRANE FUEL CELLS 8, PTS 1 AND 2 Vol. 16 ( 2 ) page： 1961 - 1965 2008

Hasegawa Naoki, Asano Takashi, Hatanaka Tatsuya, Kawasumi Masaya, Morimoto Yu

PROTON EXCHANGE MEMBRANE FUEL CELLS 8, PTS 1 AND 2 Vol. 16 ( 2 ) page： 1713 - 1716 2008

Study on water content of perfluorosulfonic acid ionomer membranes below water freezing point

A. Koiwai, A. Kamiya and M. Kawasumi

Vol. 11 ( 1 ) page： 587 - 587 2007.9

Degradation of Nafion Membranes in Hydrogen Peroxide

K. Kodama, F. Miura, N. Hasegawa, M Kawasumi and Y. Morimoto

ECS Meeting Abstracts Vol. MA2005-02 ( X2 - Durability and Reliability of Low-Temperature Fuel Cells and Fuel Cell Systems ) page： 1185 - 1185 2006

The discovery of polymer-clay hybrids

Kawasumi M

JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY Vol. 42 ( 4 ) page： 819 - 824 2004.2

Cell performances of direct methanol fuel cells with grafted membranes

Hatanaka T, Hasegawa N, Kamiya A, Kawasumi M, Morimoto Y, Kawahara K

FUEL Vol. 81 ( 17 ) page： 2173 - 2176 2002.12

Polyolefin-clay hybrids based on modified polyolefins and organophilic clay

Hasegawa N., Okamoto H., Kawasumi M., Kato M., Tsukigase A., Usuki A.

Macromolecular Materials and Engineering Vol. 280-281 ( 7-8 ) page： 76 - 79 2000

Language：English Publishing type：Research paper (scientific journal) Publisher：Macromolecular Materials and Engineering

A novel and general approach to prepare polyolefin-clay hybrids by using the maleic anhydride modified polyolefins and organophilic clay during melt-blending was reported. The silicate layers of the clay were exfoliated and homogeneously dispersed at the monolayers in the hybrids. The hybrids exhibited remarkable reinforcement compared to conventional composites filled with talc which were dispersed at micrometer level.

DOI： 10.1002/1439-2054(20000801)280:1<76::aid-mame76>3.0.co;2-#

Novel memory effect found in nematic liquid crystal/ fine particle system

Electro-Rheological Behavior of Liquid Crystal Polymers (LCPs) Dissolved in a Nematic Solvent: Dependence on Temperature and LCP Structure

Y.-C. Chiang, A. M. Jamieson, S. Campbell, T. H. Tong, N. D. Sidocky, L. C. Chien, M. Kawasumi, V. Percec

Polymer Vol. 41 ( 11 ) page： 4127 - 4135 2000

Preparation and mechanical properties of polystyrene-clay hybrids

Hasegawa N, Okamoto H, Kawasumi M, Usuki A

JOURNAL OF APPLIED POLYMER SCIENCE Vol. 74 ( 14 ) page： 3359 - 3364 1999.12

Preparation and mechanical properties of polystyrene-clay hybrids.

Hasegawa N, Okamoto H, Kawasumi M, Usuki A

ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY Vol. 217 page： U411 - U411 1999.3

Liquid Crystal/Clay Mineral Composites

Masaya Kawasumi, Naoki Hasegawa, Arimitsu Usuki, Akane Okada

Applied Clay Science Vol. 15 ( 1-2 ) page： 93 - 108 1999

Nematic liquid crystal/clay mineral composites

Kawasumi M, Hasegawa N, Usuki A, Okada A

MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS Vol. 6 ( 2-3 ) page： 135 - 143 1998.11

Preparation and mechanical properties of polypropylene-clay hybrids using a maleic anhydride-modified polypropylene oligomer

Hasegawa N, Kawasumi M, Kato M, Usuki A, Okada A

JOURNAL OF APPLIED POLYMER SCIENCE Vol. 67 ( 1 ) page： 87 - 92 1998.1

Preparation and mechanical properties of polypropylene-clay hybrids

Kawasumi M, Hasegawa N, Kato M, Usuki A, Okada A

MACROMOLECULES Vol. 30 ( 20 ) page： 6333 - 6338 1997.10

Effect of Molecular Architecture on the Electrorheological Behavior of Liquid Crystal Polymers in Nematic Solvents

Y.-C. Chiang, A. M. Jamieson, S. Campbell, Y. Lin, N. O’Sidocky, L.-C. Chien, M. Kawasumi, V. Percec

Rheologica Acta Vol. 36 ( 5 ) page： 505 - 512 1997

Electrorheological Behavior of Main-Chain Liquid Crystal Polymers Dissolved in Nematic Solvents

Y.-C. Chiang, A. M. Jamieson, M. Kawasumi, V. Percec

Macromolecules Vol. 30 ( 7 ) page： 992 - 1996 1997

Kawasumi M., Hasegawa N., Usuki A., Okada A.

Liquid Crystals Vol. 21 ( 6 ) page： 769 - 776 1996

Language：English Publishing type：Research paper (scientific journal) Publisher：Liquid Crystals

Novel liquid crystalline composites composed of a nematic two-frequency-addressing liquid crystal and organized clay mineral (about 1 wt %) have been prepared. The particles of clay mineral were dispersed homogeneously in the liquid crystal. The composite cells became transparent within 50ms when a 60 Hz electric field was applied. The transparent state was maintained after the field was switched off. It transformed into a turbid light scattering state by applying 1.5kHz electric field which caused dynamic scattering in the cell. The light transmittance of both memory states did not change after 20 h without the electric field. © 2006 Taylor & Francis.

DOI： 10.1080/02678299608032892

Reversible Electro-optical Switching of Memory Type PDLC by Two-frequency-driving

HASEGAWA Naoki, KAWASUMI Masaya, USUKI Arimitsu, OKADA Akane

Preprints of symposium on liquid crystals Vol. 22 ( 0 ) page： 399 - 400 1996

Language：Japanese Publishing type：Research paper (conference, symposium, etc.) Publisher：The Japanese Liquid Crystal Society

A memory type PDLC have been prepared by sandwiching a mixture of two-frequency-addressing liquid crystals and acrylate monomers with hydoroxy group between two glass substrates with ITO electrodes followed by the UV irradiation. This PDLC can be electrically switched between the transparent state and the light scattering state, which are maintained over months without electric field. This PDLC exhibited a polymer ball morphology according to SEM observation.

DOI： 10.11538/ekitouyokou.22.0_399

The Factors Affecting The Electro-optic Effect of Nematic Liquid Crystal / Fine Particles Composites System

KAWASUMI Masaya, HASEGAWA Naoki, USUKI Arimitsu, OKADA Akane

Preprints of symposium on liquid crystals Vol. 22 ( 0 ) page： 397 - 398 1996

Language：Japanese Publishing type：Research paper (conference, symposium, etc.) Publisher：The Japanese Liquid Crystal Society

The novel liquid crystalline composites cell based on a nematic two-frequency-driving liquid crystal and organized clay exhibited reversible and bistable electro-optic effects between the transparent and light scattering states. In this paper, the factors affecting the electro-optic effect of the composites were investigated. The wettability of the liquid crystal on the organized clay strongly affected to their memory capability. The memory effect decreased drastically with decreasing the clay content in the composites with clay content below 1 wt.%. Not only the composites themselves but also the treatment of the substrates affected to the electro-optic effect. The treatment for the homogeneous alignment gave the better memory effect for the transparent state.

DOI： 10.11538/ekitouyokou.22.0_397

大学大学院における高分子教育

岡田守, 板垣秀幸, 伊藤浩一, 川上雄資, カートハウスオラフ, 川角昌弥, 金仁華

高分子 Vol. 45 ( 10 ) page： 729 - 735 1996

Liquid crystalline composite based on a clay mineral

Kawasumi M, Usuki A, Okada A, Kurauchi T

MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS Vol. 281 page： 91 - 103 1996

Reversible Electro-Optical Switching of a Memory Type PDLC Memory Using Two-Frequency-Addressing Liquid Crystals

Naoki Hasegawa, Masaya Kawasumi, Arimitsu Usuki, Akane Okada

Liquid Crystals Vol. 21 ( 5 ) page： 765 - 766 1996

Novel memory effect found in nematic liquid crystal clay mineral composites Reviewed International journal

Kawasumi M, Hasegawa N, Usuki A, Okada A, Kurauchi T

LIQUID CRYSTALS FOR ADVANCED TECHNOLOGIES Vol. 425 page： 311 - 316 1996

Reversible electro-optical switching of a memory type pdlc memory using two-frequency-addressing liquid crystals memory on- state ii International journal

Hasegawa N., Kawasumi M., Usuki A., Okada A.

Liquid Crystals Vol. 21 ( 5 ) page： 765 - 766 1996

Language：English Publishing type：Research paper (scientific journal) Publisher：Liquid Crystals

A memory type PDLC has been prepared by sandwiching a mixture of two-frequencyaddressing liquid crystals and acrylate monomers with a hydoroxy group between two glass substrates with IT0 electrodes followed by UV irradiation. This PDLC can be electrically switched between a transparent state and a light scattering state, which are maintained over several months without electric fields. © 2006 Taylor & Francis.

DOI： 10.1080/02678299608032890

Molecular Structure of Nylon in Nylon 6-Clay Hybrid

USUKI Arimitsu, KAWASUMI Masaya, KOJIMA Yoshitsugu, OKADA Akane, KURAUCHI Toshio, OGAWA Tadao, ARAGA Toshimi

Vol. 52 ( 5 ) page： 299-304 1995.5

Novel preferred orientation in injection‐molded nylon 6‐clay hybrid

Kojima Y., Usuki A., Kawasumi M., Okada A., Kurauchi T., Kamigaito O., Kaji K.

Journal of Polymer Science Part B: Polymer Physics Vol. 33 ( 7 ) page： 1039 - 1045 1995.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Polymer Science Part B: Polymer Physics

Nylon 6‐clay hybrid (NCH) is a molecular composite of Nylon 6 and uniformly dispersed silicate monolayers of montmorillonite. In this study the preferred orientation of montmorillonite and Nylon‐6 crystallites in a thick (3 mm) injection‐molded bar of NCH has been investigated using x‐ray diffraction and electron micrography (TEM). It is clear that this bar has a triple layer structure consisting of surface, intermediate, and middle layers which have different preferred orientation. In the surface layer both the silicate monolayers and the chain axes of Nylon‐6 crystallites are parallel to the bar surface though the latter are randomly oriented within the plane. In the intermediate layer the silicate monolayers remain parallel to the bar surface but the Nylon‐6 crystallites rotate by 90° so that the chain axes would be perpendicular to the bar surface or the silicate monolayers. In the middle layer the silicate monolayers are randomly oriented around the flow axis of the NCH bar while remaining parallel to it, and the Nylon crystallites are randomly oriented around the flow axis while keeping their chain axes perpendicular to the silicate monolayers. It may be concluded that such preferred orientation of Nylon 6 crystallites is induced by the clay because the crystallites in the pure Nylon 6 bar have no preferred orientation. ©1995 John Wiley & Sons, Inc. Copyright © 1995 John Wiley & Sons, Inc.

DOI： 10.1002/polb.1995.090330707

Interaction of nylon 6‐clay surface and mechanical properties of nylon 6‐clay hybrid

Usuki A., Koiwai A., Kojima Y., Kawasumi M., Okada A., Kurauchi T., Kamigaito O.

Journal of Applied Polymer Science Vol. 55 ( 1 ) page： 119 - 123 1995.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Applied Polymer Science

We synthesized nylon 6‐clay hybrid materials using four types of clay minerals, montmorillonite, saponite, hectrite, and synthetic mica. The mechanical properties of their injection molded specimens were measured according to ASTM. Nylon 6‐clay hybrid using montmorillonite was superior to the other hybrids in mechanical properties. This might result from the difference in the interaction between nylon molecules and silicates in the hybrids. To clarify this hypothesis, we synthesized intercalated compounds of the clay minerals with glycine as the model of the hybrids, and analyzed the interaction using 15N cross polarization magic angle spinning (CP/MAS) NMR spectroscopy. The 15N‐NMR result reveals that the positive charge density on the nitrogen of the intercalated compound based on montmorillonite was largest in all the intercalated compounds. It was suggested that montmorillonite interacted strongly with nylon 6 by ionic interaction. This ionic interaction was one of the reasons why these hybrid materials had superior mechanical properties. © 1995 John Wiley & Sons, Inc. Copyright © 1995 John Wiley & Sons, Inc.

DOI： 10.1002/app.1995.070550113

Liquid Crystalline Polymers with Cyclic and Hyperbranched Structures

KAWASUMI Masaya

Kobunshi Vol. 44 ( 7 ) page： 448 - 448 1995

Viscoelastic Properties of Dilute Nematic Mixtures Containing Cyclic and Hyperbranched Liquid Crystal Polymers Dissolved in a Nematic Solvent

Fu‐Lung ‐L Chen, A. M. Jamieson, M. Kawasumi, V. Percec

Journal of Polymer Science Part B: Polymer Physics Vol. 33 ( 8 ) page： 1213 - 1223 1995

Conformational Behavior of the Spacer in a Liquid Crystalline Main-Chain Polymer in Its Nematic and Glassy States

J. Leisen, C. Boeffel, H. W. Spiess, D. Y. Yoon, M. H. Sherwood, M. Kawasumi, V. Percec

Macromolecules Vol. 28 ( 20 ) page： 6937 - 6941 1995

SANS Study of a Semiflexible Main Chain Liquid Crystalline Polyether

F. Hardouin, G. Sigaud, M. F. Achard, A. BrÛlet, J. P. Cotton, D. Y. Yoon, V. Percec, M. Kawasumi

Macromolecules Vol. 28 ( 16 ) page： 5427 - 5433 1995

Synthesis and Properties of Diamine-Modified Nylon 6-Clay Hybrid.

USUKI Arimitsu, KAWASUMI Masaya, KOJIMA Yoshitsugu, OKADA Akane, KURAUCHI Toshio

KOBUNSHI RONBUNSHU Vol. 52 ( 7 ) page： 440 - 444 1995

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Society of Polymer Science, Japan

In this report, we added hexamethylene diamine (HMDA) to nylon 6-clay hybrid (NCH), in which some silicate layers were laminated and these laminated layers were dispersed in the nylon 6 matrix. The diamine-modified NCH had sufficient elongation and impact strength. However, the strength and modulus slightly decreased. The silicate layers were pillared by diammonium ion of the diamine in the diamine-modified NCH. It is considered that the decrease of mechanical properties results in a lowering of the surface area between the silicate layers and nylon 6.

DOI： 10.1295/koron.52.440

Molecular Structure of Nylon in Nylon 6-Clay Hybrid.

USUKI Arimitsu, KAWASUMI Masaya, KOJIMA Yoshitsugu, OKADA Akane, KURAUCHI Toshio, OGAWA Tadao, ARAGA Toshimi

KOBUNSHI RONBUNSHU Vol. 52 ( 5 ) page： 299 - 304 1995

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Society of Polymer Science, Japan

The molecular structure of nylon in nylon 6-clay hybrid (NCH), in which clay silicates were dispersed uniformly, was analyzed using a field desorption mass spectrometer. The main peaks of fragment ions from the mass spectrum of NCH, were classified into ion groups. Two possible molecular structures of NCH were postulated supposing different locations of the copolymerized nylon 12 monomer unit (12-aminolauric acid) which was intercalated in the clay prior to the polymerization to enhance the miscibility between the clay and nylon 6. We compared the experimental fragment ion groups with those from the expected structures. From these results, it became clear that nylon 12 monomer units did not exist only at the end of nylon 6, but also occur randomly along the nylon 6 main chain. NCH without having any 12-aminolauric acid units was proved to have improved thermal properties.

DOI： 10.1295/koron.52.299

FINE-STRUCTURE OF NYLON-6-CLAY HYBRID Reviewed International journal

KOJIMA Y, USUKI A, KAWASUMI M, OKADA A, KURAUCHI T, KAMIGAITO O, KAJI K

JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS Vol. 32 ( 4 ) page： 625 - 630 1994.3

Molecular Recognition Directed Self-Assembly of Supramolecular Architectures

V. Percec, J. Heck, G. Johansson, D. Tomazos, M. Kawasumi, P. Chu, G. Ungar

Journal of Macromolecular Science, Part A Vol. 31 ( 11 ) page： 1719 - 1758 1994

Molecular Order in the Nematic Melt of a Semiflexible Polyether by Deuteron NMR

M. H. Sherwood, G. Sigaud, D. Y. Yoon, C. G. Wade, M. Kawasumi, V. Percec

Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals Vol. 254 ( 1 ) page： 455 - 468 1994

At the Borderline Between Glassy, Crystalline and Liquid Crystalline Macrocyclics

V. Percec, M. Kawasumi

Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals Vol. 238 ( 1 ) page： 21 - 37 1994

Toward ‘Willowlike’ Thermotropic Dendrimers Reviewed

V. Percec, P. Chu, M. Kawasumi

Macromolecules Vol. 27 ( 16 ) page： 4441 - 4453 1994

Molecular Recognition Directed Self-Assembly of Supramolecular Liquid Crystals

V. Percec, J. Heck, G. Johansson, D. Tomazos, M. Kawasumi, P. Chu, G. Ungar

Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals Vol. 254 ( 1 ) page： 137 - 196 1994

SORPTION OF WATER IN NYLON-6 CLAY HYBRID

KOJIMA Y, USUKI A, KAWASUMI M, OKADA A, KURAUCHI T, KAMIGAITO O

JOURNAL OF APPLIED POLYMER SCIENCE Vol. 49 ( 7 ) page： 1259 - 1264 1993.8

One‐pot synthesis of nylon 6–clay hybrid International journal

Kojima Y., Usuki A., Kawasumi M., Okada A., Kurauchi T., Kamigaito O.

Journal of Polymer Science Part A: Polymer Chemistry Vol. 31 ( 7 ) page： 1755 - 1758 1993.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Polymer Science Part A: Polymer Chemistry

Nylon 6–clay hybrid is a molecular composite of nylon 6 and uniformly dispersed silicate layers of montmorillonite. One‐pot synthesis of the hybrid was carried out by the following procedures. Montmorillonite was dispersed in water, and then ε‐caprolactam, acid (phosphoric acid, hydrochloric acid, benzenesulfonic acid, isophthalic acid, trichloroacetic acid, or acetic acid), and 6‐aminocaproic acid were added to the dispersion. The mixtures were reacted at 260°C for 6 h, yielding the nylon 6–clay hybrids (1potNCHs). X‐ray diffraction revealed that the silicate layers of 1potNCH by phosphoric acid were uniformly dispersed in the nylon 6 matrix. The 1potNCH had excellent mechanical properties. The strength and the modulus of the hybrid increased compared with previously reported nylon 6–clay hybrid (NCH) synthesized by montmorillonite intercalated with 12‐aminolauric acid. The heat distortion temperature (HDT) of the 1potNCH was 160°C, which was 8°C higher than that of NCH. In other 1potNCHs, montmorillonite had a smaller effect on the increase of those properties, and interlayer spacing of montmorillonite was observed at ca. 20 Å. © 1993 John Wiley & Sons, Inc. Copyright © 1993 John Wiley & Sons, Inc.

DOI： 10.1002/pola.1993.080310714

MECHANICAL-PROPERTIES OF NYLON 6-CLAY HYBRID

KOJIMA Y, USUKI A, KAWASUMI M, OKADA A, FUKUSHIMA Y, KURAUCHI T, KAMIGAITO O

JOURNAL OF MATERIALS RESEARCH Vol. 8 ( 5 ) page： 1185 - 1189 1993.5

SWELLING BEHAVIOR OF MONTMORILLONITE CATION EXCHANGED FOR OMEGA-AMINO ACIDS BY EPSILON-CAPROLACTAM Reviewed

USUKI A, KAWASUMI M, KOJIMA Y, OKADA A, KURAUCHI T, KAMIGAITO O

JOURNAL OF MATERIALS RESEARCH Vol. 8 ( 5 ) page： 1174 - 1178 1993.5

SYNTHESIS OF NYLON 6-CLAY HYBRID

USUKI A, KOJIMA Y, KAWASUMI M, OKADA A, FUKUSHIMA Y, KURAUCHI T, KAMIGAITO O

JOURNAL OF MATERIALS RESEARCH Vol. 8 ( 5 ) page： 1179 - 1184 1993.5

Synthesis of nylon 6–clay hybrid by montmorillonite intercalated with ϵ‐caprolactam International journal

Kojima Y., Usuki A., Kawasumi M., Okada A., Kurauchi T., Kamigaito O.

Journal of Polymer Science Part A: Polymer Chemistry Vol. 31 ( 4 ) page： 983 - 986 1993.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Polymer Science Part A: Polymer Chemistry

It was found that montmorillonite was intercalated with ϵ‐caprolactam. X‐ray diffraction revealed that the chain axes of the ϵ‐caprolactam were parallel to the montmorillonite plates. The intercalated montmorillonite was swollen by molten ϵ‐caprolactam at 200°C. ϵ‐Caprolactam and 6‐aminocaproic acid (accelerator) were polymerized with the intercalated montmorillonite at 260°C for 6 h, yielding a nylon 6‐clay hybrid. X‐ray diffraction and transmission electron micrography revealed that the silicate layers of the hybrid were uniformly dispersed in the nylon 6 matrix. Mechanical properties of the hybrid were improved. The strength and the modulus of the hybrid increased compared with the previously reported nylon 6 clay‐hybrid (NCH) synthesized by montmorillonite intercalated with 12‐aminolauric acid. The heat distortion temperature (HDT) of the hybrid was 164°C, which was 12°C higher than that of NCH. © 1993 John Wiley & Sons, Inc. Copyright © 1993 John Wiley & Sons, Inc.

DOI： 10.1002/pola.1993.080310418

Gas Barrier Properties of Nylon 6-Clay Hybrid.

KOJIMA Yoshitsugu, USUKI Arimitsu, KAWASUMI Masaya, OKADA Akane, KURAUCHI Toshio, KAMIGAITO Osami

Materials life Vol. 5 ( 1/2 ) page： 13 - 17 1993

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：MATERIALS LIFE SOCIETY, JAPAN

Nylon 6-clay hybrid (NCH) is a molecular composite of nylon 6 and uniformly-dispersed silicate layers of montmorillonite. Gas permeabilities in NCH films were measured to estimate the gas barrier properties. Montmorillonite crystal layers assume planar orientation in NCH. Crystallinity of nylon 6 in NCH was a little larger than that of nylon 6. The gas permeability in NCH decreased with the increase in the montmorillonite content. NCH had a good gas barrier properties compared with nylon 6. The superior gas barrier properties of NCH are ascribed to the increase of tortuosity factor due to the planar orientation of montmorillonite crystal layers.

DOI： 10.11338/mls1989.5.13

Synthesis and Liquid Crystallinity of Cyclic Polyethers Containing Mesogenic Units in Their Main Chains

KAWASUMI Masaya, PERCEC Virgil

Preprints of symposium on liquid crystals Vol. 19 ( 0 ) page： 208 - 209 1993

Liquid-Crystalline Polyethers Based on Conformational Isomerism. 31. Absence of Chiral Molecular Recognition in Irregular Linear and Macrocyclic Liquid-Crystalline Polyethers Based on 1-(4-Hydroxy-4’-Biphenylyl)-2-(4-Hydroxyphenyl) butane and α,ω-Dibromoalkanes

V. Percec, M. Kawasumi

Macromolecules Vol. 26 ( 15 ) page： 3917 - 3928 1993

機能性液晶高分子

川角昌弥

豊田中央研究所R&D レビュー Vol. 28 ( 4 ) page： 13 - 24 1993

Mechanical Properties of Nylon 6-Clay Hybrid Reviewed

Yoshitsugu Kojima, Arimitsu Usuki, Masaya Kawasumi, Akane Okada, Yoshiaki Fukushima, Toshio Kurauchi, Osami Kamigaito

Journal of Materials Research Vol. 8 ( 5 ) page： 1185 - 1189 1993

Synthesis of Nylon 6-Clay Hybrid Reviewed

Arimitsu Usuki, Yoshitsugu Kojima, Masaya Kawasumi, Akane Okada, Yoshiaki Fukushima, Toshio Kurauchi, Osami Kamigaito

Journal of Materials Research Vol. 8 ( 5 ) page： 1179 - 1184 1993

Swelling Behavior of Montmorillonite Cation Exchanged for ω-Amino Acids by ε-Caprolactam

Arimitsu Usuki, Masaya Kawasumi, Yoshitsugu Kojima, Akane Okada, Toshio Kurauchi, Osami Kamigaito

Journal of Materials Research Vol. 8 ( 5 ) page： 1174 - 1178 1993

Macrocycles with Clearing Temperatures Higher than Their Linear High-Molecular-Weight Homologues

V. Percec, M. Kawasumi

Journal of Materials Chemistry Vol. 3 ( 7 ) page： 725 - 734 1993

Similarities and Differences between the Mesomorphic Behavior of Oligomeric Macrocyclics and of Linear High Relative Molecular Mass Polyethers Based on 1-(4’-Hydroxybiphenyl-4-yl)-2-(4-Hydroxyphenyl) butane and Flexible Spacers

V. Percec, M. Kawasumi

Journal of the Chemical Society, Perkin Transactions Vol. 1 ( 12 ) page： 1319 - 1334 1993

Transformation of a Kinetically Controlled Nematic Phase of a Linear Polymer into One Which Is Thermodynamically Controlled via Cyclization

V. Percec, M. Kawasumi

Liquid Crystals Vol. 13 ( 1 ) page： 83 - 94 1993

Liquid Crystalline Polyethers Based on Conformational Isomerism. Part 28. Noncrystallizable Macrocyclics Exhibiting Enantiotropic Liquid-Crystalline Phases

V. Percec, M. Kawasumi

Chemistry of Materials Vol. 5 ( 6 ) page： 826 - 834 1993

Liquid-Crystalline Polyethers Based on Conformational Isomerism. 32. Effect of Molecular Weight on the Phase Behavior of Linear and Macrocyclic Oligoethers and of Linear Polyethers Based on 1-(4-Hydroxy-4’-biphenylyl)-2-(4-hydroxyphenyl) butane and 1,10-Dibromodecane

V. Percec, M. Kawasumi

Macromolecules Vol. 26 ( 14 ) page： 3663 - 3675 1993

Dynamic Light Scattering from Nematic Monodomains Containing Mesogenic Polymers of Differing Architectures

G. Dongfeng, A. M. Jamieson, M. Kawasumi, M. S. Lee, V. Percec

Macromolecules Vol. 25 ( 8 ) page： 2151 - 2155 1992

Synthesis and Characterization of a Thermotropic Nematic Liquid Crystalline Dendrimeric Polymer

V. Percec, M. Kawasumi

Advanced Materials Vol. 4 ( 9 ) page： 572 - 576 1992

Synthesis and Characterization of Cyclic Liquid Crystalline Oligomers Based on 1-(4-Hydroxy-4’-Biphenylyl)-2-(4-Hydroxyphenyl) butane and 1,10-Dibromodecane Reviewed

V.　Percec, M. Kawasumi, P. L. Rinaldi, V. E. Litman

Macromolecules Vol. 25 ( 15 ) page： 3851 - 3861 1992

Light Scattering from a Nematic Monodomain in an Electric Field Twist Elastic Constant and Viscosity Coefficient of Nematic Polymer–Solvent Mixtures

D. F. Gu, A. M. Jamieson, M. S. Lee, M. Kawasumi, V. Percec

Liquid Crystals Vol. 12 ( 6 ) page： 961 - 971 1992

Liquid-Crystalline Polyethers Based on Conformational Isomerism. 18. Polyethers Based on a Combined Mesogenic Unit Containing Rigid and Flexible Groups: 1-(4-Hydroxy-4’-Biphenyl)-2-(4-Hydroxyphenyl) butane

V. Percec, M. Kawasumi

Macromolecules Vol. 24 ( 23 ) page： 6318 - 6324 1991

Scaling law for elastic modulus in filler-reinforced composite materials Invited Reviewed

A Koiwai, M Kawasumi, S Hyodo, T Motohiro, S Noda, O Kamigaito

"Benibana" International Symposium on How to Improve the Toughness of Polymers and Composites--Toughness, Fracture and Fatigue of Polymers and Composites page： 105 - 110 1990

A solid state NMR study on crystalline forms of nylon 6

Okada A., Kawasumi M., Tajima I., Kurauchi T., Kamigaito O.

Journal of Applied Polymer Science Vol. 37 ( 5 ) page： 1363 - 1371 1989.2

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Applied Polymer Science

High‐resolution 13C‐NMR spectra were studied for two different crystalline structures of nylon 6 in the solid state by the cross polarization/magic angle spinning (CP/MAS) method. Two crystalline structures, α‐form and γ‐form, gave different chemical shifts for methylene carbons. The results showed that the hydrogen bonds between intermolecular chains are stronger in the γ‐form than in the α‐form. This strongly supports the results of the X‐ray study of nylon 6 by Malta et al. Our results also showed that interamolecular delocalization of positive charges occurs in the γ‐form through hyperconjugation in which the dihedral angle between the π bond and neighboring σ bonds is 30° while no such effect can be expected in the α‐form in which the angle is 0°. Copyright © 1989 John Wiley & Sons, Inc.

DOI： 10.1002/app.1989.070370519

Vinylbenzyl-type polyamide macromer synthesized from bicyclic oxalactam. Preparation and characterization of graft copolymer composed of polystyrene as a stock and hydrophilic polyamide as branches.

SWELLING BEHAVIOR OF MONTMORILLONITE BY POLY-6-AMIDE Reviewed International journal

FUKUSHIMA Y, OKADA A, KAWASUMI M, KURAUCHI T, KAMIGAITO O

CLAY MINERALS Vol. 23 ( 1 ) page： 27 - 34 1988.3

Hashimoto Kazuhiko, Sumitomo Hiroshi, Kawasumi Masaya

Polymer Journal Vol. 17 ( 9 ) page： 1045 - 1054 1985.9

Language：English Publishing type：Research paper (scientific journal) Publisher：The Society of Polymer Science, Japan

Vinylbenzyl-type polyamide macromers (1) of various average molecular weights (Mn; 3900, 5400, and 8400) were prepared by the anionic ring-opening polymerization of a bicyclic oxalactam, 8-oxa-6-azabicyclo[3.2.1]octan-7-one (abbreviated as BOL, 2) followed by a reaction with p-vinylbenzylamine. The relative reactivity of the macromer (M1) in the radical copolymerization with styrene (M2) was found to be lower than that of p-methylstyrene from the estimation of the reciprocal monomer reactivity ratio (1/r2). The resulting graft copolymer composed of a polystyrene stock and polyamide branches was characterized by structural analysis, solubility test, and determination of moisture sorption. Two kinds of transparent binary blend films, which were i) the graft copolymer and homopolystyrene and ii) the graft copolymer and polyBOL, were cast on a glass plate from the corresponding chloroform and chloroform-methanol (9:1) solutions, respectively. In the case of the former film comprising mainly polystyrene, the hydrophilic polyamide segment of the graft copolymer as a really minor component was found to be located on the glass-side surface from the contact angle measurement and the attenuated total reflection-infrared spectroscopy.

DOI： 10.1295/polymj.17.1045