Faculty Profiles - KAWASUMI Masaya

Papers - KAWASUMI Masaya

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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

Web of Science

Scopus

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

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Scopus

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

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Scopus

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

Web of Science

CiNii Research

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

Scopus

CiNii Research

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

Web of Science

Scopus

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

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Papers - KAWASUMI Masaya