POLYMERS Vol.68 No.4
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Fillers: Magical Powders and Spices
COVER STORY: Highlight Reviews
Obsercation and Simulation of Fillers in Rubber for Vehicle Tires Yuya SHINOHARA, Hiroyuki KISHIMOTO
<Abstract> Addition of filler to rubbery materials improves mechanical and viscoelastic properties. This reinforcement effect plays a significant role in using the nanocomposite as vehicle tires. Filler particles form a hierarchical and polydisperse structure, which makes it difficult to obtain their microscopic structure and dynamics experimentally. The presence of hierarchical structure also demands advanced simulation techniques as well as a high performance computer. In this article, we briefly describe the recent study on rubber used for vehicle tires, particularly focusing on the use of X-ray and neutron scattering. We also introduce the use of large-scale simulation coupled with X-ray and neutron scattering studies.
Keywords: Reinforcement Effect / Filler / X-Ray and Neutron Scattering
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Invention of Optical Hybrid Materials Having High Refractive Index and Abbe’s Number using ZrO2 Nanoparticles Seigou KAWAGUCHI, Kazushi ENOMOTO
<Abstract> A versatile and promising organic-inorganic hybridization method is described for the fabrication of highly transparent organic-inorganic hybrid bulk materials containing highly crystalline ZrO2 nanoparticles (NPs). The two key technologies are the surface-treatment, hydrophobization, and functionalization of ZrO2 NPs originally dispersed in water and their nanodispersion into a polymer continuous phase without any coagulation and/or agglomeration. A unique and fascinating surface treatment method is demonstrated in which the hydrophobization and phase transfer of ZrO2 NPs from water to toluene is simultaneously achieved. Transparent surface-modified ZrO2 nanodispersions in toluene are obtained by a gentle solvent exchange from a ternary solvent mixture composed of water, toluene, and methanol. The surface-treated ZrO2 NP powders after drying possess the ability of re-dissolution or nanodispersion in several organic solvents and vinyl monomers. Optically transparent polystyrene and poly(methyl methacrylate) hybrid bulk materials with thicknesses of 10 mm are fabricated. Furthermore, the technique is applied to the hybridization of ZrO2 NPs and epoxy-based polymers. Their refractive indices and Abbe’s numbers are quantitatively described by the Lorentz-Lorenz effective medium expansion theory. The present method provides promising candidates for different transparent hybrid optical materials consisting of inorganic and organic materials.
Keywords: Refractive Index / Optical Polymer / Organic-Inorganic Hybrids / Surface Treatment / Abbe’s Number / Nanodispersion
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COVER STORY: Topics and Products
Development of AlN Whisker Filler for High-Thermal Conductive Resin and Start-up Company Toru UJIHARA
<Abstract> Thermal management technology becomes important to remove heat from various types of device. We developed AlN whisker fillers which can improve thermal conductivity of resin materials. By adding 35 vol% AlN to resin materials, the thermal conductivity of the resin materals with 35 vol% AlN whisker filler is above 10 W/mK. Recently the start-up company was founded. We already provides the onerous samples to 40 companies over. The requirements and clames from the users of the onerous samples are valuable to enhance the research and development.
Keywords: Thermal Conductiviry / Filler / Whisker / AlN / Resin / Start-Up / Venture Business
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Transparent Conductive Film using Silver Nanowires Shigeru YAMAKI
<Abstract> Silver nanowires are attracting attention as an alternative material for indium tin oxide (ITO) due to their unique conductivity and transparency. Our group has synthesized and refined silver into a nanowire shape suitable for transparent conductive films. Further, by selecting the binder resin and optimizing printing conditions, a film having high transparency and conductivity was obtained. Even when the film was allowed to stand in an oven at 100℃ for 1,000 hours, the change in resistance value was 20% or less. It also had excellent flexibility.
Keywords: Silver Nano Wiers / AgNW / Transparent Condactive Film
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Functional Filler Filling Polymer Electrolyte Membrane Keiji SHITO, Akito MASUHARA
<Abstract> Silica particles coated with proton conductive layers and hydrophobic layers composed of block copolymers were successfully prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization with particles (PwP). The experimental results verified the successful formation of poly(acrylic acid)-b-polystyrene coated silica particles and achieved low activation energy. In addition, Coating with a polystyrene layer allows the proton conductive structure to be maintained in a wide humidity range.
Keywords: Polymer Electrolyte Membrane / Proton Conduction / Filler / PAA-b-PS / RAFT Polymerization
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Development of Carbon Nanotube/Polyamide Nanocomposite Reverse Osmosis Membranes Kenji TAKEUCHI, Takuya HAYASHI, Morinobu ENDO
<Abstract> Carbon nanotubes (CNT) are a leading material of the emerging nanotechnology, and have contributed to environment and renewable energy era. We are working to apply such advanced CNT to form a thin composite as active layer for reverse osmosis (RO) membranes. The robustness of our recently developed RO membrane made of CNT and polyamide (PA) nanocomposites is demonstrated as new carbon-based membranes with superior antifouling/chlorine resistance. Theoretical approaches based on computational chemistry were carried out to explain these specific performances of CNT/PA membranes. We hope these new membranes and the related science can contribute to a breakthrough beyond the well-developed, conventional membrane technology for a new era of water and nanotechnology applications.
Keywords: Carbon Nanotube / Reverse Osmosis Membrane / Antifouling
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Polymer Science and I: A Personal Account
“Egotistic” and “Theme of Beethoven’s Symphony No.5” Kyosuke ISODA
<Abstract> Since I have been a lecturer in Kagawa University, I have got conceited. However, lab’s members (students) saved me from my attitude of irresponsibility and gave me a lot of chances to change.
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Front-Line Polymer Science
Recent Progress in Polymer Solar Cells Hideo OHKITA, Hyung Do KIM, Yasunari TAMAI
<Abstract> Polymer solar cells have attracted increasing attention recently because they are lightweight, flexible, and colorful, and in addition, are suitable for high-throughput production by printing techniques. In this review, we will describe recent progress in polymer solar cells in terms of photovoltaic conversion mechanism and efficiency. As for the photovoltaic conversion mechanism, recent studies have shown that an energy offset in the HOMO or LUMO level would be not necessary for excitons to be dissociated into free charge carriers in polymer solar cells. This is one of the hottest topics in this community. As for the photovoltaic performance, ternary blends and non-fullerene acceptors have a great impact on the improvement in power conversion efficiency. As a result, the efficiency has exceeded 17% for tandem polymer solar cells based on non-fullerene ternary and binary blends. We also mention the future direction of polymer solar cells.
Keywords: Polymer Solar Cell / Conjugated Polymer / Fullerene / Non-Fullerene Acceptor / Ternary Blend / Transient Absorption Spectroscopy / Tandem Solar Cell
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