| POLYMERS Vol.72 No.10 |
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COVER STORY
Polymers Connecting Humans and the Earth |
| COVER STORY: Highlight Reviews |
| Lignin as Future Circulative Aromatic Carbon Resources | Hikaru TAKAYA |
| <Abstract> Lignin is the second most abundant plant-derived aromatic carbon resource on Earth after cellulose, and is an unused carbon resource. This review article tries to show what lignin will be a key polymer material that connects human beings and the earth to achieve a recycling-oriented society. Recent progress and prospects of chemical upconversion of lignin as a recyclable aromatic resource are reviewed with representative research works. Keywords: Lignin / Lignin First / Woody Biomass / Biorefinery / Cellulose / Hemicellulose / Recyclable Resource / Chemical Recycle |
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| Precision Polymerization of Plant-Derived Compounds | Kotaro SATOH, Tomohiro KUBO |
| <Abstract> In recent years, various efforts have been under consideration to develop sustainable polymer materials. There have been increasing reports to explore the creation of new plastics using natural plant-derived substances as renewable raw materials. This airticle focuses on the synthesis methods of plant-derived bio-based polymers especially using precision polymerization technique that has been evolved with the development of petrochemical-based polymer chemistry. Keywords: Bio-Based Polymer, Precision Polymerization, Plant-Derived Renewable Monomer |
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| CO2 Capture by Polymeric Membranes | Ikuo TANIGUCHI |
| <Abstract> Membrane separation has attracted much attention as a next-generation CO2 capture technology, and various CO2 separation membranes have been developed. Among them, polymeric membranes are considered to hold potential for use from viewpoints of large area and mass production, product homogeneity and stability, cost effectiveness, and so on. Herein, the transition of CO2 separation membrane research, the state-of-the-art research and development cases, and the challenges toward implementation will be introduced. Keywords: CO2 / Diffusion / Gas Separation / Membrane / Permeability / Solubility / Selectivity |
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| Stimuli-Mediated Biodegradation | Tadahisa IWATA |
| <Abstract> Can we develop a dreamlike biodegradable plastic that continuously demonstrates excellent functions when in use, and when leaked into the environment, biodegradation is initiated by external stimuli, eventually leading to complete degradation to water and carbon dioxide? I would like to introduce the current status of the development of a challenging function required of biodegradable plastics, the “biodegradation start switch on!”. Keywords: Biodegradable Plastics / Biodegradation Stimuli / Biodegradation Mechanism / pH Stimuli / Enzyme-Embedded Biodegradable Plastic / Marine Biodegradation / Enzymatic Degradation |
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| COVER STORY: Topics and Products |
| Marine Biodegradable Plastics Triggered by a Switch Function in Response to Reductive Stimuli | Yuya TACHIBANA, Toyokazu TSUTSUBA, Ken-ichi KASUYA |
| <Abstract> Although biodegradable plastics have been attracting attention as a solution to plastic pollution, some of them hardly degrade in the ocean. Our previous studies have shown that the rate-determining step of the environmental degradation depends on biological processes, which generate low molecular weight molecules. In order to ensure that plastics can be degraded anywhere, the steps that determine the rate of degradation should not depend on biological processes, but rather on environmental stimuli. The oxidation-reduction potential (ORP) is a suitable environmental stimulus and the disulfide bond is known as a reduction-responsive group, which undergoes a reductive cleavage under low ORP condition to form two thiol groups. We demonstrated the biodegradation control of polyesters containing disulfide bonds and revealed that disulfide bonds in polymers can function as a switch for the initiation of biodegradation. Keywords: Biodegradable Polymer / Marine Degradation / Reductive Cleavage / Disulfide Bond / Switch Function / Poly(Butylene Succinate) |
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| Screening for Environmental Pollutants Using Moleculaly Imprinted Polymers | Takuya KUBO |
| <Abstract> Ministry of the Environment has encouraged to specify a substance that is required a risk management, seek an unknown substance and figure out their disposition on EXTEND 2022 and Japan Environment and Children's Study (JECS). This study constructed an innovational screening technique that can evaluate biding activity of receptors through only the result of chemical analysis using estrogen receptor (ER) and thyroid hormone receptor (TR) that have a large number of reports on information of receptor structures. We developed the assessment technique of ER and TR biding activity using a method of like chromatography with a receptor imitated separation medium. Furthermore, identifying substances of ER or TR activity contribution in environmental analytes, we revealed disposition of compounds through animal experiments. This study makes possible an application for not only ER and TR but also chemical substances having a lot of receptors binding activity, opening the door to acquisition of academic perceptions such as a resolution for physiological mechanisms. Keywords: Molecularly Imprinting / Estrogen Receptor / Thyroid Hormone Receptor / Receptor Imitated / Chromatography / Screening |
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| Contribution of Polyglycolic Acid to the Energy Business | Takuma KOBAYASHI |
| <Abstract> In recent years, biodegradable plastics have been attracting attention as a material that contributes to reducing environmental damage. Polyglycolic acid, PGA, one of such plastics, is biodegradable and has excellent mechanical properties, and applications that take advantage of these features in the field of hydrocarbon resource recovery. A frac plug is one of the tools used in the hydraulic fracturing process for shale gas and oil recovering. Non-degradable materials have been conventionally applied and a process of breaking them down with a specific tool is necessary when recovering resources. By applying degradable frac plugs made of PGA, the process can be eliminated or minimized because they can withstand high water pressure and automatically degrade. Temporary plugging materials are used when water leakage occurs while drilling a formation. Calcium carbonate is usually used, but acid treatment is required to remove them. Applying PGA as temporary plugging materials eliminates the acid treatment and contributes to high efficiency. Keywords: Polyglycolic Acid / Degradability / Gas and Oil Recovery |
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| Polymer Science and I: A Personal Account |
| My Eyes Opened by Polymer and Synchrotron X-Ray | Yohei NAKANISHI |
| <Abstract> Polymers and synchrotron X-rays helped me to determine my career direction as a researcher. Making scientific contributions to spatial distribution and correlation analysis of sulfur and zinc in vulcanized EPDM rubber using μ-XRF is one of my major achievements. I started using neutron beam technology to investigate polymer microstructures as well. |
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| Front-Line Polymer Science |
| End-Functionalized Polymerization via C-H Bond Activation Mediated by Early Transition Metal Complexes | Haruki NAGAE, Kazushi MASHIMA |
| <Abstract> We review end-functionalized polymerizations via C-H bond activation mediated by early transition metal complexes. In the case of polyolefin synthesis, the C-H bond activation of an organic molecule is the key step to generate the corresponding complex that acts as an initiator. During the polymerization, the organic molecule performs as a chain-transfer agent to regenerate the initiator through s-bond metathesis between the C-H bond of the organic molecule and metal-carbon bond at the growth terminal. Recently, this excellent protocol was applied to alternating copolymerization of carbon dioxide and epoxides to give end-functionalied polycarbonate monools and telechelic polycarbonate diols. Keywords: End-Functionalized Polymerization / C-H Bond Activation / Early Transition Metal Complexes / Polyolefin / Polycarbonate / Carbon Dioxide / Epoxide / Alternating Copolymerization |
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