| POLYMERS Vol.65 No.11 |
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COVER STORY
Adhesives and Polymers |
| COVER STORY: Topics and Products |
| Molecular Explication of Fracture Mechanism | Hiroya KODAMA |
| <Abstract> Aiming to improve the strength of polymeric materials dramatically, intensive research seeks to achieve big advancement in “Tough Polymers” which is one of the ImPACT-Programs of the Cabinet Office, government of Japan. Since high research technologies such as the intensive use of the K-computer or SPring-8 should be promoted openly within the program, we established a common subject, “Molecular Explication of Fracture Mechanism”. The goal of the subject is to obtain new guidlines of advanced material design. The outline of our study on the subject is indroduced. Keywords: Fracture Toughness / Ductile-Brittle Transition / Crack Propagation |
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| Self-Healing Polymers | Hideyuki OTSUKA |
| <Abstract> Self-healing polymers can be expected to contribute to the extension of polymer lifetime, reduction of waste, and the development of reliable restorative materials. The idea of self-healing polymers was spotlighted as accessible materials by a pioneering work in the beginning of this century. The work employed the encapsulation of a “healing agent” (in this case, a bifunctional monomer) that would be released after a crack in the polymer breached the microcapsules, and subsequently the agent polymerized after contact with an initiator or catalyst embedded within the polymer matrix. Since this seminal work, plenty of self-healing materials have been reported and some are now available commercially. More strategies toward the development of self-healing polymers have been proposed. Both physical and chemical strategies have been explored, with the latter further classified into three separate branches, making use of healing agents, non-covalent interactions, and reversible covalent bonds. Keywords: Self-Healing / Toughness / Cross-Linked Polymers / Microcapsules / Supramolecular Chemistry / Dynamic Covalent Chemistry / Polymer Reactions |
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| Frontier Visualization Technology for Polymer Structural Chemistry via Synchrotron Radiation | Masaki TAKATA |
| <Abstract> Of particular importance for structural polymer chemistry is to develop advanced methodology of visualization. The latest topics of synchrotron radiation (SR) application to structural polymer chemistry science are described about new scheme to exploit industry-academia collaboration, advanced endstation construction for the “ImPACT Tough Polymer Project”, etc. As future prospective of polymer structure SR visualization, needs of new light source project, SLiT-J project, is particularly noted. Keywords: Synchrotron Radiation / Polymer Structural Cemistry / Industry Academia Collaboration |
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| Developing Ultra-Thin and Tough Proton Exchange Membranes (PEMs) for Polymer Electrolyte Fuel Cells (PEFCs) | Shin TATEMATSU |
| <Abstract> When looking toward the widespread commercialization of FC vehicles, it is necessary to develop a more efficient and compact PEFC system that can operate under conditions of low humidity and high temperature. Although the use of thinner membranes with a higher ion exchange capacity (IEC) is preferable because it can reduce internal resistance and enhance water back diffusion, resulting in much better FC performance, it usually reduces the mechanical strength of the membrane, owing to a higher degree of membrane swelling. As one of the participating companies in a Cabinet Office sponsored program, Impulsing Paradigm Change through Disruptive Technologies (ImPACT), with the help and support from academia, we have been developing fluorine-based ultra-thin and tough PEMs with higher proton conductivity. Our development strategy is to increase the IEC of the material, improve the chemical structure of hydrophobic domains, and optimize physical properties of hydrophilic domains. Keywords: Fuel Cell / Thin Film Electrolyte / Polymer Electrolyte Membrane / Mechanical Strength / Mechanical Durability / Membrane Resistance |
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| Ultra-Thin and Flexible Tough Polymers, Towards Automotive Application | Kiyoshi TAKAGI |
| <Abstract> Nissan participates in the ImPACT “Ultra-Thin and Flexible Tough Polymers” project aiming at advanced automotive applications. Values and targets are outlined for 4 key applications. In the study of lithium iron batteries, the thinning of the separator contributes to the increase of energy density. It is a big challenge for a polymer to be durable with Li dendrite as well as to meet strength, porosity and gurley requirements. Polymer electrolyte membranes are a big subject in fuel cell studies. A good membrane needs a thinned structure for size and cost reduction. Polymers have to be designed from aspects like insulator properties, proton transport, H2 & O2 impermeability and H2O permeability. Carbon Fiber Reinforced Polymer (CFRP) is considered a key material for vehicle weight reduction. CFRP needs energy absorption and fracture mode comparable with aluminum in high speed deformation to expand its application. New molecular concepts are to be introduced to modify the needed characteristics. Polymer glass should give us styling freedom in the cockpit in the era of autonomous driving. Material development of tough polymers and nano fillers contributes to the improvement of rigidity and impact performance. Keywords: Polymer / Automotive / Battey / Fuel Cell / Body Structure / Glass |
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| Hope for Contribution to Sustainable Society by ImPACT | Masahiko HIRAO |
| <Abstract> Life Cycle Assessment (LCA) has been developed for evaluating the environmental impacts of product life cycles from extraction of resources to waste disposal. It is widely used in various fields of industry for product design and improvement. For example, the Carbon-LCA method developed by the international council of chemical associations can evaluate the environmental benefit by using chemical products from the life cycle perspective. However, there are many challenges for applying LCA to innovative technologies, such as “Ultra-Thin and Flexible Tough Polymers” to be developed by the ImPACT project. We have to construct possible life cycle systems by forecasting and estimate the input-output data of each stage by modeling. Furthermore, a method for decision making by an integrated evaluation and interpretation of various kinds of impacts on the environment, economy and society is needed. We hope that the “Tough Polymers” will contribute for achieving a number of global goals adopted in the united nation’s “Sustainable Development Goals” (SDGs). Keywords: Sustainable Society / Life Cycle Assessment / Innovative Technology / Tough Polymer / SDGs / Social Impact |
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| Polymer Science and I: A Personal Account |
| Something between Boss and Me | Kosuke OKEYOSHI |
| <Abstract> Closing to a boss in one meter, his/her aura is definitely impressive. From their eyes, some energetic messages/passion are originating from their memory with high intensity. This communication is similar to a moment when faced with a surprising phenomena during experiments. |
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| Front-Line Polymer Science |
| Development of Highly Functional Injectable Polymer Systems | Yuichi OHYA |
| <Abstract> Biodegradable polymer solutions exhibiting temperature-responsive sol-gel transition between room temperature and body temperature can be applied as injectable polymer (IP) systems for biomedical applications such as less-invasive drug delivery systems. Block copolymers of aliphatic polyesters and PEG are well known as such biodegradable IP. However, several issues were cited for clinical application of the biodegradable IP systems. In this review, recent approaches to solve these issue would be introduced. For example, IP hydrogel are likely to revert to the sol state under highly wet conditions after injection into the body. On this issue, we developed an IP formulation forming a chemically cross-linked hydrogel in response to temperature change to achive longer duration time of the gel state under highly wet conditions in the body. These improvements would be helpful for the clinical application of the IP systems. Keywords: Injectable Polymers / Sol-Gel Transition / Temperature-Responsive / Biodegradable Polymers / Drug Delivery System / Less-Invasive Therapy / Smart Biomaterials |
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