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Author

Yoshiharu Kimura

Other affiliations: Teijin, Shimadzu Corp., Kyoto University
Bio: Yoshiharu Kimura is an academic researcher from Kyoto Institute of Technology. The author has contributed to research in topics: Polymerization & Copolymer. The author has an hindex of 51, co-authored 321 publications receiving 9081 citations. Previous affiliations of Yoshiharu Kimura include Teijin & Shimadzu Corp..
Topics: Polymerization, Copolymer, Lactide, Fiber, Polyester


Papers
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Journal ArticleDOI
11 Mar 2016-Science
TL;DR: In this paper, a new bacterium, Ideonella sakaiensis 201-F6, was found to be able to use PET as its major energy and carbon source, producing two enzymes capable of hydrolyzing PET and the reaction intermediate, mono(2-hydroxyethyl) terephthalic acid.
Abstract: Poly(ethylene terephthalate) (PET) is used extensively worldwide in plastic products, and its accumulation in the environment has become a global concern. Because the ability to enzymatically degrade PET has been thought to be limited to a few fungal species, biodegradation is not yet a viable remediation or recycling strategy. By screening natural microbial communities exposed to PET in the environment, we isolated a novel bacterium, Ideonella sakaiensis 201-F6, that is able to use PET as its major energy and carbon source. When grown on PET, this strain produces two enzymes capable of hydrolyzing PET and the reaction intermediate, mono(2-hydroxyethyl) terephthalic acid. Both enzymes are required to enzymatically convert PET efficiently into its two environmentally benign monomers, terephthalic acid and ethylene glycol.

1,417 citations

Journal ArticleDOI
TL;DR: Neo-PLA as discussed by the authors is a bio-based poly(L-lactide) (PLLA) prepared by fermentation and polymerization, which can be formed by simple polymer blend of PLLA and PDLA or more easily with stereoblock polylactides (sb-PLA).
Abstract: Polymeric materials prepared from renewable natural resources are now being accepted as “bio-based polymers”, because they are superior to the conventional petroleum-based polymers in reducing the emission of carbon dioxide. Among them, poly(L-lactide) (PLLA) prepared by fermentation and polymerization is paid an immediate attention. Although PLLA exhibits a broad range of physico-chemical properties, its thermal and mechanical properties are somewhat poorer for use as ordinary structural materials. For improving these inferior properties, a stereocomplex form consisting of PLLA and its enantiomer poly(D-lactide) (PDLA) has high potential because of showing high melting nature (230 °C). It can be formed by simple polymer blend of PLLA and PDLA or more easily with stereoblock polylactides (sb-PLA) which are PLLA/PDLA block copolymers. These novel PLA polymers, named “Neo-PLA”, can provide a wide range of properties that have never be attained with single PLLA. Neo-PLA retains sustainability or bio-based nature, because both monomers L- and D-lactic acids are manufactured from starch by fermentation. Copyright © 2006 Society of Chemical Industry

388 citations

Journal ArticleDOI
TL;DR: PET degrading microorganisms and the enzymes involved, along with the evolution of PHEs to address the issues that hamper microbial and enzymatic PE...
Abstract: Most petroleum-derived plastics, as exemplified by poly(ethylene terephthalate) (PET), are chemically inactive and highly resistant to microbial attack. The accumulation of plastic waste results in environmental pollution and threatens ecosystems, referred to as the “microplastic issue”. Recently, PET hydrolytic enzymes (PHEs) have been identified and we reported PET degradation by a microbial consortium and its bacterial resident, Ideonella sakaiensis. Bioremediation may thus provide an alternative solution to recycling plastic waste. The mechanism of PET degradation into benign monomers by PET hydrolase and mono(2-hydroxyethyl) terephthalic acid (MHET) hydrolase from I. sakaiensis has been elucidated; nevertheless, biodegradation may require additional development for commercialization owing to the low catalytic activity of these enzymes. Here, we introduce PET degrading microorganisms and the enzymes involved, along with the evolution of PHEs to address the issues that hamper microbial and enzymatic PE...

282 citations

Journal ArticleDOI
01 Feb 2000-Polymer
TL;DR: In this paper, a series of acylated chitosans were synthesized by reacting chitosa with hexanoyl, decanoyal, and lauroyl chlorides, which exhibited an excellent solubility in organic solvents such as chloroform, benzene, pyridine, and transparent films were obtained from these solutions.

246 citations

Journal ArticleDOI
TL;DR: In this article, it was discovered that Sn(II) catalysts activated by various proton acids can produce high molecular weight poly(L-lactic acid) [weight-average molecular weight (Mw ≥ 100,000] in a relatively short reaction time (≤15 h).
Abstract: Poly(L-lactic acid) (PLLA) was produced by the melt polycondensation of L-lactic acid. For the optimization of the reaction conditions, various catalyst systems were examined at different temperature and reaction times. It was discovered that Sn(II) catalysts activated by various proton acids can produce high molecular weight PLLA [weight-average molecular weight (Mw ) ≥ 100,000] in a relatively short reaction time (≤15 h) compared with simple Sn(II)-based catalysts (SnO, SnCl2 · 2H2O), which produce PLLA with an Mw of less than 30,000 after 20 h. The new catalyst system is also superior to the conventional systems in regard to racemization and discoloration of the resultant polymer. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1673–1679, 2000

235 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a literature review is presented regarding the synthesis, and physicochemical, chemical, and mechanical properties of poly(lactic acid)(PLA), with an orthorhombic unit cell.
Abstract: A literature review is presented regarding the synthesis, and physicochemical, chemical, and mechanical properties of poly(lactic acid)(PLA). Poly(lactic acid) exists as a polymeric helix, with an orthorhombic unit cell. The tensile properties of PLA can vary widely, depending on whether or not it is annealed or oriented or what its degree of crystallinity is. Also discussed are the effects of processing on PLA. Crystallization and crystallization kinetics of PLA are also investigated. Solution and melt rheology of PLA is also discussed. Four different power-law equations and 14 different Mark–Houwink equations are presented for PLA. Nuclear magnetic resonance, UV–VIS, and FTIR spectroscopy of PLA are briefly discussed. Finally, research conducted on starch–PLA composites is introduced.

3,242 citations

Journal ArticleDOI
TL;DR: Reaction Mechanism, Synthesis of Urea and Urethane Derivatives, and Alcohol Homologation 2382 10.1.
Abstract: 4.3. Reaction Mechanism 2373 4.4. Asymmetric Synthesis 2374 4.5. Outlook 2374 5. Alternating Polymerization of Oxiranes and CO2 2374 5.1. Reaction Outlines 2374 5.2. Catalyst 2376 5.3. Asymmetric Polymerization 2377 5.4. Immobilized Catalysts 2377 6. Synthesis of Urea and Urethane Derivatives 2378 7. Synthesis of Carboxylic Acid 2379 8. Synthesis of Esters and Lactones 2380 9. Synthesis of Isocyanates 2382 10. Hydrogenation and Hydroformylation, and Alcohol Homologation 2382

3,203 citations

Journal ArticleDOI
TL;DR: Polylactic acid is proving to be a viable alternative to petrochemical-based plastics for many applications It is produced from renewable resources and is biodegradable, decomposing to give H2O, CO2, and humus, the black material in soil as mentioned in this paper.
Abstract: Polylactic acid is proving to be a viable alternative to petrochemical-based plastics for many applications It is produced from renewable resources and is biodegradable, decomposing to give H2O, CO2, and humus, the black material in soil In addition, it has unique physical properties that make it useful in diverse applications including paper coating, fibers, films, and packaging (see Figure)

2,537 citations

Journal ArticleDOI
TL;DR: Kevin Shakesheff investigates new methods of engineering polymer surfaces and the application of these engineered materials in drug delivery and tissue engineering.
Abstract: s, and 360 patents, and edited 12 books. He has also received over 80 major awards including the Gairdner Foundation International Award, Lemelson-MIT prize, ACS’s Applied Polymer Science and Polymer Chemistry Awards, AICHE’s Professional Progress, Bioengineering, Walker and Stine Materials Science and Engineering Awards. In 1989, Dr. Langer was elected to the Institute of Medicine of the National Academy of Sciences, and in 1992 he was elected to both the National Academy of Engineering and the National Academy of Sciences. He is the only active member of all three National Academies. Kevin Shakesheff was born in Ashington, Northumberland, U.K., in 1969. He received his Bacheclor of Pharmacy degree from the University of Nottingham in 1991 and a Ph.D. from the same institution in 1995. In 1996 he became a NATO Postdoctoral Fellow at MIT, Department of Chemical Engineering. He is currently an EPSRC Advanced Fellow at the School of Pharmaceutical Sciences, The University of Nottingham. His research group investigates new methods of engineering polymer surfaces and the application of these engineered materials in drug delivery and tissue engineering. 3182 Chemical Reviews, 1999, Vol. 99, No. 11 Uhrich et al.

2,532 citations

Journal ArticleDOI
TL;DR: The impacts of RGD peptide surface density, spatial arrangement as well as integrin affinity and selectivity on cell responses like adhesion and migration are discussed.

2,443 citations