研究者詳細 - 木田　拓充

論文 - 木田　拓充

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Temperature Dependence of Strain-Hardening Behavior of Polyethylene Solids Evaluated by SAXS, WAXD, and Raman Spectroscopy 査読

Sanshiro Kimura, Takumitsu Kida, Hiroki Takeshita, Katsuhisa Tokumitsu

Macromolecules 2025年3月

Raman spectroscopic observation of conformational changes during thermal exposure and its effects on melting and crystallization behavior of high-density polyethylene 査読

Yusuke Hiejima, Hikaru Kawada, Takumitsu Kida, Koh-hei Nitta

Polymer Degradation and Stability 232 111152 - 111152 2025年2月

Facile synthesis of macroscopic bilayer gels by one-shot radical polymerization in phase-separated binary solvent systems 査読

Shohei Ida, Ryuto Soma, Iori Ono, Takumitsu Kida, Shokyoku Kanaoka

Polymer Journal 2024年12月

Effects of Mixing Ultra-High Molecular Weight Polyethylene on Morphology and Mechanical Properties of Polyethylene Solids 査読

Takumitsu Kida, Shiori Watanabe, Nobuhiro Kasai, Takahiro Nagahama, Takashi Kamitanaka, Hiroki Takeshita, Katsuhisa Tokumitsu

Nihon Reoroji Gakkaishi 52 ( 4 ) 265 - 271 2024年9月

Effect of mixing temperature on the dispersion and degradation behaviors of HDPE/UHMWPE blends 査読

Shiori Watanabe, Sayaka Yamada, Nobuhiro Kasai, Takumitsu Kida, Hiroki Takeshita, Katsuhisa Tokumitsu

International Polymer Processing 39 ( 5 ) 557 - 567 2024年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Walter de Gruyter GmbH

Abstract

There is currently considerable interest in high-density polyethylene (HDPE)/ultra-high-molecular-weight polyethylene (UHMWPE) blends as recyclable all-polyolefin materials with favorable mechanical properties that can be processed by continuous melt-mixing. Optimal mixing is required to improve the mechanical properties of polymer blends by ensuring their dispersibility and low degradation. In the present study, we investigated the effects of mixing temperature on the dispersion and degradation behaviors of HDPE/UHMWPE blends. Neat HDPE and a HDPE blend comprising 5 % UHMWPE were obtained by melt-mixing while changing the input energy in an internal batch mixer under a nitrogen atmosphere. The temperature of the mixer was set at 200 °C for neat HDPE, and at 180, 200, and 220 °C for the HDPE/UHMWPE blends. Optical microscopy and thermal analysis revealed that the dispersion of UHMWPE in HDPE was accelerated at higher mixing temperatures. However, in the high input energy range, mixing at 200 °C resulted in the most favorable dispersion. Gel permeation chromatography and rheological measurements suggested that chain scission and branching/crosslinking due to degradation were accelerated at higher mixing temperatures, even when mixing in a nitrogen atmosphere. Chemiluminescence measurements suggested that chain scission and branching/crosslinking were caused by an initial oxidation reaction. Furthermore, for the same input energy, the maximum shear stress increased as the mixing temperature decreased, but the mixing time and thermal history increased as the mixing temperature increased. The results suggest that in a blend comprising HDPE and UHMWPE, mixing at the molecular level due to high temperature and fine dispersion of UHMWPE due to shear stress proceed simultaneously. On the other hand, the results also confirmed that degradation was more influenced by the promotion of oxidation due to high temperatures and prolonged mixing than by shear stress.

DOI： 10.1515/ipp-2024-0041

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その他リンク： https://www.degruyter.com/document/doi/10.1515/ipp-2024-0041/pdf

Neutron Reflectivity Study on the Adsorption Layer of Polyethylene Grown on Si Substrate 査読

Keisuke Shimokita, Katsuhiro Yamamoto, Noboru Miyata, Motoki Shibata, Yohei Nakanishi, Masato Arakawa, Mikihito Takenaka, Takumitsu Kida, Katsuhisa Tokumitsu, Ryo Tanaka, Takeshi Shiono, Masako Yamada, Hideki Seto, Norifumi L. Yamada, Hiroyuki Aoki, Tsukasa Miyazaki

Langmuir 2024年7月

Antiplasticizing effect of triethyl citrate on an isosorbide-based polycarbonate 査読

Ruiqi Han, Takumitsu Kida, Masayuki Yamaguchi

Journal of Polymer Research 31 ( 8 ) 219 2024年7月

Effect of short-chain branches in high-molecular-weight component on tensile properties of polyethylene solids 査読

Takumitsu Kida, Ryo Tanaka, Takeshi Shiono, Hiroki Takeshita, Katsuhisa Tokumitsu

Polymer 126906 - 126906 2024年3月

In-situ Raman spectroscopic study of conformational reorganization during heat treatment for high-density polyethylene solid 査読

Misato Nabata, Takumitsu Kida, Yusuke Hiejima, Koh-hei Nitta

Polymer 290 126558 - 126558 2024年1月

Optimum processing conditions for the maximum crystallization rate of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) 査読

Janchai K., Kida T., Yamaguchi M., Sunagawa T., Okura T.

Scientific Reports 13 ( 1 ) 2023年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Scientific Reports

The effect of thermal and shear histories on the crystallization rate of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) was studied. As with other crystalline polymers, the shear history greatly affected the crystallization rate when the shear rate was beyond a critical value, i.e., the inverse of the Rouse relaxation time. Even after the formation of extended chain crystals, spherulite texture was clearly discernable. It grew from certain points on the extended chain crystals. Consequently, a row of spherulites appeared along the flow direction. The resin temperature in the molten state was also significant. When the sample was heated to 170 °C, which is beyond the main melting peak in the differential scanning calorimetry curve, unmolten crystals did not affect the linear viscoelastic properties. They acted as effective nucleating agents for the rest of the polymer during cooling. Therefore, the shear history hardly affected the crystallization rate and the number of spherulites.

DOI： 10.1038/s41598-023-27595-3

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その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85146106118&origin=inward

Compressive double yielding in high-density polyethylene over a wide range of strain rates 査読

Yusuke Hiejima, Nobuhiro Misumi, Ryohei Ippitsu, Takumitsu Kida, Masahiro Higuchi, Hiroyuki Yamada, Koh-hei Nitta

Polymer 291 126590 - 126590 2023年12月

Rheological Properties of poly(Lactic acid) Modified by Cellulose Acetate Propionate 査読

Takeyoshi Kimura, Tomoki Takeuchi, Panitha Phulkerd, Pornchanok Pichaipanich, Daisuke Kugimoto, Shingo Kouda, Takumitsu Kida, Masayuki Yamaguchi

Journal of Polymers and the Environment 2023年10月

Modification of melt memory effect by addition of poly(butylene terephthalate) to thermoplastic polyester elastomer 査読

Takumi Yamada, Takumitsu Kida, Masayuki Yamaguchi

Polymer 285 126330 - 126330 2023年10月

Morphological transformation of extruded isotactic polypropylene film from the Mesophase to α-form crystals 査読

Takumitsu Kida, Yuta Fukuda, Masayuki Yamaguchi, Yasuhiko Otsuki, Tokutaro Kimura, Tomoaki Mizukawa, Tomoya Murakami, Kazuki Hato, Tomoya Okawa

Reactive and Functional Polymers 191 105682 - 105682 2023年10月

Mechanical properties of isotactic polypropylene with nodular or spherulite morphologies 査読

Yuta Fukuda, Takumitsu Kida, Masayuki Yamaguchi

Polymer Engineering & Science 2023年9月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Wiley

Abstract

α‐form crystalline isotactic polypropylene (PP) was prepared by two methods: quenching from the melt state at slow or high crystallization rates. The mechanical properties of the resulting PP samples were evaluated using tensile and stress–relaxation tests to investigate the influence of nodular or spherulite morphologies. PP samples with different morphologies had almost the same crystallinity after annealing at 100°C for 5 h. The yielding stress, strain‐hardening modulus, and strength of the nodular PP were higher than those of the spherulite PP, although the crystallinity was almost the same for both PP samples. Furthermore, the relaxation time during the stress–relaxation process at ε = 4.0 was longer for the nodular PP than for the spherulite PP. The lamellar structure of a spherulite morphology comprises parent and daughter lamellar crystals, whereas that of a nodular morphology prepared via a mesophase structure comprises only parent lamellar crystals. The formation of the daughter lamellae reduces the number of tie chains. Therefore, the nodular PP has more tie chains than the spherulite PP. This transformation from a spherulite to a nodular morphology improved the mechanical properties of the PP.

Highlights

Influences of morphology on mechanical properties of polypropylene (PP).

Tensile properties were higher for nodular PP than spherulite PP.

Relaxation time of nodular PP was longer than spherulite PP.

Nodular PP has more tie chains, resulting in improvements of tensile properties.

DOI： 10.1002/pen.26504

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Enhancing the Mechanical Properties of Poly(vinyl alcohol) Fibers by Lithium Iodide Addition 査読

Yusuke Taoka, Riza Asmaa Saari, Takumitsu Kida, Masayuki Yamaguchi, Kazuaki Matsumura

ACS Omega 8 ( 36 ) 32623 - 32634 2023年8月

Flow-induced crystallization behavior of high-density polyethylene evaluated by Rheo-Raman spectroscopic system 査読

Takumitsu Kida, Khunanya Janchai, Katsuhisa Tokumitsu, Masayuki Yamaguchi

Polymer Journal 2023年7月

Viscoelastic properties of copolycarbonates comprising isosorbide and 1,4-cyclohexanedimethanol 査読

Ruiqi Han, Takumitsu Kida, Masayuki Yamaguchi

Colloid and Polymer Science 2023年7月

Anomalous Postprocessing Dimensional Change of Injection-Molded Products Composed of Poly(lactic acid) and Poly(vinyl alcohol) 査読

Yamaguchi M., Shu W., Kimura T., Vo H.G.D., Kida T., Mori T., Kitani M., Aridome N., Miyamoto A.

ACS Applied Polymer Materials 5 ( 3 ) 2136 - 2143 2023年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Applied Polymer Materials

The present study revealed that an injection-molded product comprising poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVAL) exhibited an anomalous dimensional change, i.e., expansion in the flow direction, after postprocessing annealing (around 2.9% expansion by annealing at 80-100 °C for 3 h). Although the crystallization of the PLA during cooling was not accelerated by the addition of PVAL, the PLA showed transcrystallization from the dispersed PVAL droplets, which were deformed in the flow direction, during postprocessing annealing. Therefore, after annealing, the injection-molded products exhibited a high degree of molecular orientation, in contrast to the original unannealed products, which were not oriented. This anomalous behavior should be noted as a means of controlling dimensional change after processing.

DOI： 10.1021/acsapm.2c02155

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その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85149045515&origin=inward

Role of Shear Flow on Structure Development during Post-Processing Annealing for Poly(lactic acid) 査読

Vo H.G.D., Kida T., Yamaguchi M.

Polymers 15 ( 3 ) 2023年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Polymers

The effect of shear history on structure development during post-processing annealing was studied using poly(lactic acid) PLA. Since PLA shows a low crystallization rate, quenched films had no crystallinity. Moreover, molecular orientation was not detected in the films. During the annealing procedure beyond its glass transition temperature, however, molecular orientation to the flow direction occurred with the crystallization growth in the films having an appropriate shear history. This peculiar crystal growth during the annealing was most probably attributed to the crystallization from extended chain crystals generated during the applied shear history, although the amount of extended chain crystals was low. The results obtained in this study should be noted because the molecular orientation proceeded due to the annealing history applied. Furthermore, this phenomenon will be used to suppress dimensional change and increase product rigidity.

DOI： 10.3390/polym15030693

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その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85148000207&origin=inward

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