研究者詳細 - 木田　拓充

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85126982688&origin=inward

Polymerization of Styrene Derivatives Using Anilinonaphthoquinone-Ligated Nickel Complexes and Thermal/Rheological Properties of the Produced Polymers 査読

Chowdhury S.I., Kida T., Tanaka R., Nakayama Y., Shiono T.

Macromolecular Chemistry and Physics 223 ( 1 ) 2022年1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：Macromolecular Chemistry and Physics

Polystyrenes (PStX, X = -H, -OMe, -Me, or -Cl at 4-position) are synthesized by the use of anilinonaphthoquinone-ligated nickel complexes [Ni(C10H5O2NAr)(Ph)(PPh3): 1a, Ar = C6H3-2,6-iPr; 1b, Ar = C6H2-2,4,6-Me; 1c, Ar = C6H5] activated with modified methylaluminoxane (MMAO) in toluene. The polymer yield is dependent on the substituent X and decreases in the following order: -OMe > -Me > -H >> -Cl. The highest weight-average molecular weight (Mw) of 107 000 with polydispersity (Ð) of 1.4 is achieved for PStOMe by the 1a-MMAO catalytic system. 13C NMR analysis indicated that the polymers obtained at 70 °C are atactic but those obtained at 0 °C are isotactoid (isotactic triad ≈ 74 ̶ 82 %), which depended on X. The linear viscoelasticity measurement is also performed to investigate the influences of the substituent on the rheological properties. The critical molecular weight of the chain entanglement of PStOMe is higher than that of PStMe, which should be due to the suppression of the chain entanglement by the methoxy group.

DOI： 10.1002/macp.202100402

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85119260485&origin=inward

Effect of Ultra-High-Molecular-Weight Molecular Chains on the Morphology, Crystallization, and Mechanical Properties of Polypropylene 査読国際誌

Takumitsu Kida, Takeyoshi Kimura, Ayaka Eno, Khunanya Janchai, Masayuki Yamaguchi, Yasuhiko Otsuki, Tokutaro Kimura, Tomoaki Mizukawa, Tomoya Murakami, Kazuki Hato, Tomoya Okawa

Polymers 13 ( 23 ) 4222 - 4222 2021年12月

担当区分：筆頭著者,　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：MDPI AG

The effects of the ultra-high-molecular-weight (UHMW) component of polypropylene (PP) on its rheological properties, crystallization behavior, and solid-state mechanical properties were investigated using various measurement techniques. The terminal relaxation time—determined by measuring the linear viscoelasticity—was increased by adding the UHMW component. The increase in the melt elasticity produced by adding the UHMW component was observed by measuring the steady-state shear flow, although the shear viscosity was not greatly affected. Owing to the long characteristic time of the Rouse relaxation of the UHMW component, PP with the UHMW component formed highly oriented structures through a shear-induced crystallization process. The addition of the UHMW component enhanced the orientation and regularity of crystalline structure for extruded films. Therefore, the Young′s modulus, yield stress, and strength were higher in the PP film containing the UHMW component than in one without the UHMW component, irrespective of the direction of tensile deformation.

DOI： 10.3390/polym13234222

PubMed

Impact of Magnesium Salt on the Mechanical and Thermal Properties of Poly(vinyl alcohol) 査読

分子量分布および短鎖分岐構造がポリエチレンの一軸引張り挙動に与える影響査読

木田拓充

次世代ポリオレフィン総合研究 14 45 - 49 2021年12月

Riza Asmaa Saari, Muhammad Shahrulnizam Nasri, Takumitsu Kida, Masayuki Yamaguchi

Polymers 13 ( 21 ) 3760 - 3760 2021年10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：MDPI AG

The effects of magnesium salts with various anion species on the structure and properties of a poly(vinyl alcohol) (PVA) film were studied. The glass transition temperature of the PVA film increased following the addition of a magnesium salt. Furthermore, the salt greatly enhanced the modulus and yield stress and reduced the crystallinity of the film. These effects were attributed to the strong ion–dipole interactions between the magnesium salts and the PVA chains. The strength of interaction, i.e., the reduction of segmental motions, depended on the anion species in the following order: Mg(ClO4)2, MgBr2, MgCl2, Mg(CH3COO)2, and MgSO4. The order corresponded to the Hofmeister series, which predicts the ability to break the structure of water.

DOI： 10.3390/polym13213760

Rheological properties of linear and short-chain branched polyethylene with nearly monodispersed molecular weight distribution 査読

Takumitsu Kida, Yuya Doi, Ryo Tanaka, Takashi Uneyama, Takeshi Shiono, Yuichi Masubuchi

Rheologica Acta 60 511 - 519 2021年7月

担当区分：筆頭著者,　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：Springer Science and Business Media LLC

DOI： 10.1007/s00397-021-01286-0

その他リンク： https://link.springer.com/article/10.1007/s00397-021-01286-0/fulltext.html

Improving the strength of polyethylene solids by simple controlling of the molecular weight distribution 査読

Takumitsu Kida, Ryo Tanaka, Yusuke Hiejima, Koh-hei Nitta, Takeshi Shiono

Polymer 218 123526 - 123526 2021年3月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Elsevier BV

We prepared model polyethylene (PE) samples that contain the controlled-amounts of the high-molecular-weight component by blending a monodispersed PE into a polydispersed PE, to elucidate the influence of the high-molecular-weight component of a polymer on its mechanical properties. The strength and strain-hardening modulus were significantly enhanced by the addition of a monodispersed PE of sufficiently high molecular weight, and the critical value of M was determined to be ~3.0 × 10 . The improved strength and strain-hardening modulus are attributed to higher amounts of inter-cluster links that bridge adjacent lamellar cluster units because these links act as stress transmitters between these units. w 5

DOI： 10.1016/j.polymer.2021.123526

Incorporation of Boronic Acid Functionality into Isotactic Polypropylene and Its Application as a Cross-Linking Point 査読

Ryo Tanaka, Hiroya Fujii, Takumitsu Kida, Yuushou Nakayama, Takeshi Shiono

Macromolecules 54 ( 3 ) 1267 - 1272 2021年2月

Synthesis of thermoplastic elastomers with high biodegradability in seawater 査読

Lamya Zahir, Takumitsu Kida, Ryo Tanaka, Yuushou Nakayama, Takeshi Shiono, Norioki Kawasaki, Naoko Yamano, Atsuyoshi Nakayama

Polymer Degradation and Stability 184 109467 - 109467 2021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：Elsevier BV

As a promising biodegradable and biorenewable alternative to ubiquitous petrochemical plastics, poly(L-lactide) (PLLA) can be widely employed in biomedical and pharmaceutical fields. In this work, triblock copolymers, poly(L-lactide)-b-poly(2-methyl-1,3-propanediyl adipate)-b-poly(L-lactide) (PLLA-b-PMPA-b-PLLA)s, were synthesized by two-step polymerization from 2-methyl-1,3-propanediol (MP), adipic acid (AA) and L-lactide (LLA) as new biodegradable thermoplastic elastomers. The copolymers exhibited glass-transition temperature at below -40 degrees C and melting temperature at 140-160 degrees C. These copolymers showed much higher elongation at break and lower tensile modulus than those of PLLA. Enzymatic degradation tests of the obtained copolymers were performed using proteinase K and lipase PS as catalysts in hydrolysis reaction to demonstrate rapid degradation for these copolymers. Seawater biodegradability test was conducted for 28 days for each sample. The triblock copolymer and PMPA homopolymer were found to show about 50% biodegradation within 28 days representing very high biodegradable property in sea-water. (C) 2020 The Authors. Published by Elsevier Ltd.

DOI： 10.1016/j.polymdegradstab.2020.109467

Synthesis, Properties, and Biodegradability of Thermoplastic Elastomers Made from 2-Methyl-1,3-propanediol, Glutaric Acid and Lactide 査読

Lamya Zahir, Takumitsu Kida, Ryo Tanaka, Yuushou Nakayama, Takeshi Shiono, Norioki Kawasaki, Naoko Yamano, Atsuyoshi Nakayama

Life 11 ( 1 ) 43 - 43 2021年1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：MDPI AG

An innovative type of biodegradable thermoplastic elastomers with improved mechanical properties from very common and potentially renewable sources, poly(L-lactide)-b-poly(2-methyl-1,3-propylene glutarate)-b-poly(L-lactide) (PLA-b-PMPG-b-PLA)s, has been developed for the first time. PLA-b-PMPG-b-PLAs were synthesized by polycondensation of 2-methyl-1,3-propanediol and glutaric acid and successive ring-opening polymerization of L-lactide, where PMPG is an amorphous central block with low glass transition temperature and PLA is hard semicrystalline terminal blocks. The copolymers showed glass transition temperature at lower than −40 °C and melting temperature at 130–152 °C. The tensile tests of these copolymers were also performed to evaluate their mechanical properties. The degradation of the copolymers and PMPG by enzymes proteinase K and lipase PS were investigated. Microbial biodegradation in seawater was also performed at 27 °C. The triblock copolymers and PMPG homopolymer were found to show 9–15% biodegradation within 28 days, representing their relatively high biodegradability in seawater. The macromolecular structure of the triblock copolymers of PLA and PMPG can be controlled to tune their mechanical and biodegradation properties, demonstrating their potential use in various applications.

DOI： 10.3390/life11010043

Microstructural Interpretation of Influences of Molecular Weight on the Tensile Properties of High-Density Polyethylene Solids Using Rheo-Raman Spectroscopy 査読

Takumitsu Kida, Yusuke Hiejima, Koh-hei Nitta

Macromolecules 54 ( 1 ) 225 - 234 2021年

Synthesis and properties of block copolymers composed of norbornene/higher α-olefin gradient segments using ansa-fluorenylamidodimethyltitanium-[Ph3C][B(C6F5)4] catalyst system 査読

Haobo Yuan, Takumitsu Kida, Ryo Tanaka, Zhengguo Cai, Yuushou Nakayama, Takeshi Shiono

Polymer Chemistry 12 ( 2 ) 189 - 195 2021年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry (RSC)

A series of di- and triblock copolymers composed of gradient norbornene (NB)/α-olefin segments were synthesized by a (<italic>t</italic>-BuNSiMe2Flu)TiMe2-based catalyst and their physical and mechanical properties were investigated.

DOI： 10.1039/d0py01370f

Radial distribution functions of entanglements in primitive chain network simulations 査読

Yuichi Masubuchi, Takumitsu Kida, Yuya Doi, Takashi Uneyama

Nihon Reoroji Gakkaishi (J Soc Rheol Jpn) 49 ( 5 ) 337 - 345 2021年

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

Although the entanglement network among polymers has been widely investigated, the spatial distribution of entanglement nodes has been rarely discussed. In this study, we obtained the radial distribution functions (RDFs) for the entanglement nodes from the snapshots of multi-chain slip-link simulations. The model employed in this study is the primitive chain network (PCN) model, which has been validated to reproduce the entangled polymer dynamics semi-quantitatively. The statistics of captured entanglement networks were compared to those reported for the primitive path network extracted by the CReTA procedure from the full-atomistic molecular model of a polyethylene melt. In the range of distance longer than the average strand length, the network structure from PCN does not show any structural correlation, and the intra-chain correlation is close to that for Gaussian chains with non-interacting slip-links. These features are consistent with the CReTA network and the conventional assumptions made for single-chain models. Meanwhile, in the short-range, the structural correlation in PCN is much weaker than that in CReTA. This discrepancy is because the short-range structure in PCN is realized as a result of imposed fluctuations, whereas it is determined by the minimization of the primitive path in CReTA.

DOI： 10.1678/rheology.49.337

Synthesis and properties of biodegradable thermoplastic elastomers using 2-Methyl-1,3-propanediol, succinic acid and lactide 査読

Lamya Zahir, Takumitsu Kida, Ryo Tanaka, Yuushou Nakayama, Takeshi Shiono, Norioki Kawasaki, Naoko Yamano, Atsuyoshi Nakayama

Polymer Degradation and Stability 181 109353 - 109353 2020年11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：Elsevier BV

Triblock copolymers, poly(L-lactide)-b-poly(2-methyl-1,3-propanediyl succinate)-b-poly(L-lactide) (PLLA-b-PMPS-b-PLLA), were synthesized as new biodegradable thermoplastic elastomers by two-step polymerization. In the first step, hydroxy-telechelic poly(2-methyl-1,3-propanediyl succinate) (PMPS) was synthesized from 2-methyl-1,3-propanediol (MP, small excess) and succinic acid (SA) using two-stage reaction of esterification and simple polycondensation processes. In the second step, plant derived L-lactide (LLA) was polymerized using the bifunctional PMPS as a macroinitiator to synthesize PLLA-b-PMPS-b-PLLA triblock copolymers. The structures of the triblock copolymers as well as the PMPS macroinitiator were characterized by NMR and GPC analysis. PMPS is an amorphous polymer with T-g at lower than -24 degrees C. The triblock copolymers also exhibited low T-g for the PMPS segment at lower than -20 degrees C as well as T-m, at around 150 degrees C for the PLLA segment. The tensile tests of the triblock copolymers demonstrated their low modulus and high elongation. The biodegradation tests of these polymers were also performed using enzymes and seawater to reveal their biodegradability. (C) 2020 The Authors. Published by Elsevier Ltd.

DOI： 10.1016/j.polymdegradstab.2020.109353

Microscopic Origin of Elastic and Plastic Deformation in Poly(Ether-Block-Amide) Elastomers under Various Conditions 査読

Takumitsu Kida, Keisuke Hamasaki, Yusuke Hiejima, Shuichi Maeda, Koh-hei Nitta

Nihon Reoroji Gakkaishi 48 ( 3 ) 153 - 160 2020年6月

Synthesis and Properties of Gradient Copolymers Composed of Norbornene and Higher α-Olefins Using an ansa-Fluorenylamidodimethyltitanium-[Ph3C][B(C6F5)4] Catalyst System 査読

Haobo Yuan, Takumitsu Kida, Hyunchul Kim, Ryo Tanaka, Zhengguo Cai, Yuushou Nakayama, Takeshi Shiono

Macromolecules 53 ( 11 ) 4323 - 4329 2020年6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：American Chemical Society (ACS)

The copolymerization of norbornene (NB) and various alpha-olefins [1-octene (O), 1-decene (De), and 1-dodecene (Do)] was achieved with high activity using ((t)BuNSiMe(2)Flu)TiMe2 (1)-[Ph3C][B(C6F5)(4)] and 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT)-treated tri-i-butylaluminum ((Bu3Al)-Bu-i) or tri-n-octylaluminum (Oct(3)Al) as a scavenger. The catalytic systems gave NB/alpha-olefin copolymers with number-average molecular weights over 100,000 and polydispersity indices below 1.3. The copolymers possessed the gradient structure starting from the NB-rich segment to the alpha-olefin-rich terminal because of the difference of the monomer reactivity ratios between NB and alpha-olefins. Films of the copolymers were successfully molded using a melt-pressing procedure. The strain at the break of the copolymer films increased with the length of the alkyl group of the alpha-olefin accompanied by a decrease in strength. The tensile properties of the copolymers are controlled by the NB content and the M-n value. The copolymer films showed transmittance of up to 80% in the visible-light range.

DOI： 10.1021/acs.macromol.0c00431