| POLYMERS Vol.71 No.7 |
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COVER STORY
Polymers Supporting Our Convenience and Enrich Lives |
| COVER STORY: Highlight Reviews |
| Development of Flexible Tough (SHINAYAKA) Polymers: A Report on the Achievements of ImPACT (Impulsing PAradigm Change through Disruptive Technologies) program by Cabinet Office, Government of Japan | Kohzo ITO |
| <Abstract> This report describes the achievements of the project on toughening automotive polymers, for which the author served as a program manager in ImPACT (Impulsing PAradigm Change through Disruptive Technologies) program by the Cabinet Office, Government of Japan. As a result of strong collaboration between companies and universities, and fully utilizing state-of-the-art chemistry and large-scale facilities such as the synchrotron radiation (SPring-8) and supercomputer (Kei), significant progress was made in the research and development of fracture and toughening of polymers in both basic and applied aspects. Keywords: Polymer / Toughness / Automobile / Fracture / Self-Healing / Crack Propagation / Simulation / Synchrotron |
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| COVER STORY: Topics and Products |
| Polypropylene Sustaining Human’s Life, and its Major Challenges | Motoki KANENO |
| <Abstract> Plastics have continued to grow their product share through continuous improvement in catalysts, polymerization processes, polymer designs and molding processes. While plastics are expanding its application areas, as a result, environmental hazards caused by plastics are getting more and more obvious. Polypropylene is one of the most used plastics in the world because of its high heat resistance, high rigidity and well processability, and has also been facing business threats such as reduction of usage and substitution of other materials due to environmental issues. It should be expected to significantly change the future development trend and business of polypropylene. This paper introduces the current application development topics of polypropylene and the development trends for the future. Keywords: Polypropylene / Environmental Issue / Application |
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| Improvement of Property and Functionality of Polyethylene by Drawing Techniques | Hiroki UEHARA |
| <Abstract> Polyethylene has the simplest molecular architecture among conventional polymers, but also has potential possibilities of excellent property and functionality caused by trans-zigzag conformation with the smallest molecular cross-section in the crystalline state. Such molecular anisotropy has been brought out by various drawing techniques with disentanglement, achieving high mechanical properties. In contrast, the periodic arrangement of entanglements gives nanoporous membranes applicable for lithium-ion battery separators. Similar arrangement of tie-molecules also induces an actuating movement, which is available for lightweight power-assisting suits. Keywords: Polyethylene / Drawing / Property / Functionality / UHMW-PE / LLDPE / Fiber / Film |
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| The Future of Polyvinyl Chloride | Youichi UCHIDA |
| <Abstract> Polyvinyl chloride (PVC) which is one of the widely produced synthetic plastic polymers, has a polar chlorine atom in the molecule, is non-crystalline, and has good miscibility with various substances. It has the advantage of being able to control various characteristics. By compouding PVC with plasticizers, modifiers, colorants, and additives etc., the required properties such as flexibility, elasticity, impact resistance, flame retardancy, anti-virus and anti-bacterial properties can be obtained. Therefore, it is able to be said that it is a material widely used in applications. It is also suitable for mechanical recycling because it does not easily deteriorate with use for a long period of time and it is easy to be obtained as a homogeneous material during heat processing. In this article, I would like to look on to the future of PVC that contributes to sustainability. Keywords: Polyvinyl Chloride / Non-Crystalline / Flame Retardancy / Recycling |
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| Polystyrene Applications and Latest Technology Trends | Takashi TAMAKI |
| <Abstract> Polystyrene is one of the general-purpose resins and is an indispensable plastic in our daily lives. The applications of polystyrene and examples of its environmental friendliness will be presented. Mechanical recycling, chemical recycling, and polymer alloys with biomass materials are discussed. Keywords: Polystyrene / Mechanical Recycle / Chemical Recycle / Polymer Alloy / Biomass |
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| Fold Endurance Polyester Films | Shotaro NISHIO |
| <Abstract> In recent years, foldable smartphones have been launched and are attracting attention. A transparent polyimide having excellent folding endurance is used for the surface protection film, but the price is high. We have succeeded in developing “Toyobo Fold Endurance PET Film”, which is a polyester film with excellent flexibility and optical properties by our original stretching process. It was found that the folding endurance is improved by controlling the molecular orientation in the folding direction. By not strongly orienting the molecular chains in the folding direction, the folding endurance could be improved to the same level as that of transparent polyimide. Keywords: Polyester / Film / Fold Endurance / Foldable / Rollable / Display |
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| Toughness Enhancement of Transparent Acrylic Glasses | Shogo NOBUKAWA |
| <Abstract> Recently, poly(methyl methacrylate) (PMMA), which is known as “acrylic glass”, is widely used for applications in optical windows and lamp covers for automobiles, and huge water tanks in aquariums. Although PMMA has high transparency, surface hardness and weather resistance, it easily shows brittle fracture in smaller strain less than 10％. In order to improve the toughness of PMMA, hot-stretching and blending with flexible polymers are applicable. For the hot-streching technique, the chain orientation in PMMA films generates the brittle-to-ductile transition in the tensile test. During the tensile deformation, the chain orientation becomes larger in the vicinity point, which is the important factor for the enhancement of toughness. Photo-isomerization reaction of azobenzene can induce the brittle-to-ductile transition of PMMA due to the increase of free volume, which reduces the yielding stress during the tensile deformation. Keywords: Acrylic Glass / Brittle-to-Ductile Transition / Toughness Enhancement / Stretching / Chain Orientation / Azobenzene |
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| A Characteristic of ABS Resin: Recent Developments and Applications | Hajime TOMITA |
| <Abstract> A characteristic of ABS resin is that rigidity and impact-resistant balance are excellent. Further, it is used in a wide range of applications because of its excellent molding processability such as injection molding and extrusion molding and secondary processing suitability such as plating and painting. These properties are thought to be derived from the variety of “sea island structures” in which butadiene rubber is dispersed in a continuous phase consisting of acrylonitrile and styrene. The plating product is used for mainly automotive parts and washing metal fittings etc., and a metal substitute by the metal-like decoration is planned. The painting product is used for various parts such as automotive vehicles and motorcycles etc. Demand for ABS resin will continue to grow as the population grows and infrastructure develops in the world’s economic development regions in future. Keywords: ABS / AS / ABS Polymer Alloy |
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| Polymer Science and I: A Personal Account |
| Road to My Own Molecules | Ryohei YAMAKADO |
| <Abstract> When I started my research, I didn’t understand the meaning of “original research”. In this essay, I describe two typical episodes about challenges and experiences in my research life to explain why I came to want to have “my own molecules”. |
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| Front-Line Polymer Science |
| Recent Progresses in Anisotropic Hydrogels | Yasuhiro ISHIDA |
| <Abstract> Owing to their water-rich structures, which are similar to those of biological tissues, hydrogels have long been regarded as promising scaffolds for artificial tissues and organs. However, in terms of the structural anisotropy, most synthetic hydrogels are substantially different from biological systems. Synthetic hydrogels are usually composed of randomly oriented three-dimensional polymer networks whereas biological systems adopt anisotropic structures with hier- archically integrated building units. Such anisotropic structures often play essential roles in biological systems to exhibit particular functions. In this context, anisotropic hydrogels provide an entry point for exploring biomimetic applications of hydrogels. This review highlights notable studies on anisotropic hydrogels have been reported recently, with focusing on their preparation, structures, and applications. Keywords: Actuation / Anisotropy / Biomimetics / Diffusion / Hydrogels / Mechanical Properties |
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