H
Hirotaka Okamoto
Researcher at Toyota
Publications - 131
Citations - 5074
Hirotaka Okamoto is an academic researcher from Toyota. The author has contributed to research in topics: Natural rubber & Polylactic acid. The author has an hindex of 31, co-authored 129 publications receiving 4710 citations. Previous affiliations of Hirotaka Okamoto include Kyoto University & Ritsumeikan University.
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Journal ArticleDOI
Crystallization and Melting Behavior of Poly (l-lactic Acid)
Takahiko Kawai,Nelly Rahman,Go Matsuba,Koji Nishida,Toshiji Kanaya,Mitsuru Nakano,Hirotaka Okamoto,Jumpei Kawada,Arimitsu Usuki,Nobutaka Honma,Katsuhiko Nakajima,Masatoshi Matsuda +11 more
TL;DR: In this paper, the effect of the crystallization temperature on the crystal structure and its melting behavior of poly (l-lactic acid) (PLLA) have been investigated by means of wide-angle (WAXS) and small-angle X-ray scattering, optical microscopy, and differential scanning calorimetory (DSC).
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Preparation and mechanical properties of polypropylene–clay hybrids based on modified polypropylene and organophilic clay
TL;DR: In this paper, a polypropylene-clay hybrid (PPCH) was prepared by melt blending maleic anhydride modified PP and organophilic clay, and the tensile modulus of the PPCH with 5 wt % clay was 1.9 times higher than that of the matrix resin at 25°C.
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Biaxial Flow-Induced Alignment of Silicate Layers in Polypropylene/Clay Nanocomposite Foam
Masami Okamoto,Pham Hoai Nam,Pralay Maiti,Tadao Kotaka,Takashi Nakayama,Mitsuko Takada,Masahiro Ohshima,Arimitsu Usuki,Naoki Hasegawa,Hirotaka Okamoto +9 more
TL;DR: In this paper, the biaxial flow-induced alignment of clay particles along the cell boundary was identified, which helps cells to withstand the stretching force from breaking the so thin cell wall and to improve the modulus of the foam.
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Nylon 6/Na–montmorillonite nanocomposites prepared by compounding Nylon 6 with Na–montmorillonite slurry
TL;DR: In this article, a novel compounding process using Na-montmorillonite water slurry was used for preparing novel nylon 6/Na-montormillonite nanocomposites, which exhibited high strength, high modulus, high heat distortion temperature and low gas permeability compared to neat nylon 6.
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Foam processing and cellular structure of polypropylene/clay nanocomposites
Pham Hoai Nam,Pralay Maiti,Masami Okamoto,Tadao Kotaka,Takashi Nakayama,Mitsuko Takada,Masahiro Ohshima,Arimitsu Usuki,Naoki Hasegawa,Hirotaka Okamoto +9 more
TL;DR: In this paper, polypropylene (PP)/clay nanocomposites (PPCNs) were autoclave-foamed in a batch process using supercritical CO 2 at 10 MPa, within the temperature range from 130.6°C to 143.4°C, i.e., below the melting temperature of either PPCNs or maleic anhydride modified PP (PP-MA) matrix without clay.