| POLYMERS Vol.65 No.7 |
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COVER STORY
Polymers: A Good Partner of Living in the Cities |
| COVER STORY: Highlight Reviews |
| Superplasticizers for Concrete which were Originally Invented in Japan | Tsuyoshi HIRATA |
| <Abstract> Two types of superplasticisers for concrete based on β-naphthalene sulfonic acid-formaldehyde condensates (BNS) and comb-shaped polycarboxylate ether (PCE) are cement-dipersants originally invented in Japan, that are providing concrete with a wide range of industrial applications based on their specific workability that they introduce into cement suspensions. In this paper, the historical background for the invention, the working mechanism for excellent fluidity and the further subjects for research are mentioned. BNS and PCE adsorb to the surface of cement particles and disperse them with a quite low amount of water, resulting in a high strength concrete. The dispersion of BNS is due to the electrostatic repulsion by -SO3Na groups and that of PCE is due to the steric repulsion by PEG side chains. PCE has realized new durable concrete such as self-compacting concrete and ultra-high strength concrete by changing its polymer design. Now, PCE is expected to solve many demands proposed by the concrete industry, e.g. the slump retention, the improvement of sticky and viscouse consistency and cement compatibility. Keywords: BNS / PCE / Cement / Dispersion / Superplasticizer / Interparticle Potential Energy |
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| Development of Superior Thermal Insulation Film using Hollow Silica Nanoparticles | Masayoshi FUJI, Chika TAKAI |
| <Abstract> Thermal barrier and thermal insulation techniques are strongly required for a comfortable life. This paper firstly reviews conventional techniques such as films to adjust solar radiation and multi-layered glasses. Then, the superior thermal insulation film using hollow silica nanoparticles is introduced. Keywords: Hollow Silica Nanoparticle / Inorganic Template / Thermal Insulation / Solar Radiation Adjusting Film |
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| COVER STORY: Topics and Products |
| Expectations to Polymer Science from the Viewpoint of Building Science | Kazuya MITSUJI |
| <Abstract> Two important factors of “strength” and “ductility” should be considered in the structural design of buildings. Property of energy conservation is introduced by comparison of stress-strain relations of elastic and inelastic system. It is important to consider the ductility in seismic design of buildings. As the effective devices to reduce stresses, viscous and visco-elastic dampers are often installed into vibration control system and base isolated buildings. Polymer materials are applied to those viscous and visco-elastic dampers. Two researches are introduced as the applications of polymer materials to seismic resistant systems. One is about the vibration control system of timber frame by visco-elastic tape, and the other is about the seismic reinforcement of timber frame by textile belt. Those two researches adopt polymer materials as energy dissipation or seismic resistance elements and show the effective results on stress-reduce effect. The further development of application of polymer science to ductile elements is highly expected in the field of building science. Keywords: Buidling Science / Ductility / Energy Dissipation / Vibration Control / Base Isolation |
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| Sustainable Building and the Expectation for Polymer Science | Hikaru KOBAYASHI |
| <Abstract> The field of building environmental engineering is in the branch of architecture and building science, and its research subjects include: controlling indoor and outdoor environmental elements such as heat, air, light, and sound; the development and evaluation of building materials and equipment; and lowering the energy consumption of buildings. Conventionally, the interests concerning the architectural environment have been focused on the comfort and health of occupants. Recently, however, energy conservation, low carbonization, and building life extension become the major themes in the context of the global warming issues. Architecture, which is realized with proper consideration of these themes and thereby suitable for sustainable society, is called sustainable building. This paper introduces research conducted by the author on the development of desiccant air conditioning systems using polymer materials for improving air conditioning efficiency. The paper also describes expectations on polymer science in the field of building environmental engineering to realize sustainable buildings. Keywords: Sustainable Building / Energy Saving / Desiccant Air Conditioning System |
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| SRF Changes the Earthquake Resistant Design with Polymers | Shunichi IGARASHI |
| <Abstract> SRF places polyester sheets with urethane adhesive along structural members such as columns and walls, making it possible for those members to endure huge deformation and to absorb by far more energy than members reinforced by conventional methods. The choice of reinforcing material with smaller Young’s modulus and adhesive with smaller strength than those of concrete characterizes SRF. Current method of earthquake resistant design uses heavy structural materials and non-linear numerical calculation to encounter the big earthquake expected once in hundreds of years, and therefore it requires larger amount of materials to meet the load, as the design earthquake increases, as well as the manpower to perform the computation. SRF can replace considerable amount of those heavy materials with polyester sheets, and can do without complicated computations. Therefore, even in a seismic area, SRF can build a structure as light as that located in a city without the threat of earthquakes. Keywords: SRF / Polyester Sheets / Urethane Adhesive / Earthquake Resistant Design |
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| Seismic Isolation Technology Actualizes a Sustainable Society | Sadamitsu TAKEUCHI |
| <Abstract> A seismically isolated structure is designed to decouple the superstructure from the ground to prevent direct transmission of ground-shaking energy. A seismic isolation bearing serve a key function in the system. Seismic isolation bearings protect human life, property, functionality and livability by controlling transmission of ground-shaking to the superstructure. It is used for various applications in order to contribute safety and security even after seismic events. Seismic isolation bearings, made up of alternating layers of rubber and steel plates which are strongly bonded to each other in the vulcanization process, is the most popular isolating device. Recently, to evaluate performance of seismic isolation bearings, stress-strain analysis under large deformations is conducted by hyper-elastic FEM which can handle high nonlinear problems in material and geometry. Also FEM stress-strain analysis is applied to the design of the lamination structure and the fixing system of the bolts and flange. Keywords: Seismically Isolated / Laminated Rubber Bearing / FEM Analysis |
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| Development of Recycling Technology for Waste PVC Sheets | Akio KOYAMA |
| <Abstract> Various kinds of sheets made of PVC are used as a finishing material for buildings. These used PVC sheets are dumped voluminously as mixture waste. Therefore, we aim to develop a recycling technique for PVC building wastes. Here we report a new technique that can separate recycling PVC powders from PVC building wastes. Specifically, this technique is targeted at tile carpets, wallpapers and PVC waterproof sheets. Moreover, we produced new recycling sheets by recycling the PVC powder, and we evaluated the quality of the new recycling sheets. For instance, we studied the influence on the tensile properties and the durability of the new recycling sheets by taking into account different waste types and mixture rates. Finally, we found that the effect of the new recycling technique can reduce considerably the damage to the environment and the energy use. These observations indicate that the new recycling technique is able to reduce PVC building wastes and we intend to apply it for practical use. Keywords: Recycle / PVC / Wallcovering Sheet / Tile Carpet / Waterproofing Sheet / Strength / Durability / Environmental Impact |
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| Polymer Science and I: A Personal Account |
| Studying Diligently and Smartly | Arihiro KANAZAWA |
| <Abstract> One of my favorite activities is making a hot pot dish. There are a lot of similarities between cooking and chemistry (particularly when looking for a new way to make things). I think that the most appropriate approach to both studying smartly and cooking well is to devote myself diligently to everything. |
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| Front-Line Polymer Science |
| Perpendicularly Oriented Miscrophase-separated Domains of Block Copolymer Lithographic Materials | Teruaki HAYAKAWA |
| <Abstract> The directed self-assembly (DSA) of block copolymers (BCPs) can realize next-generation lithography for semiconductors. It is essential to simultaneously achieve many requirements such as a high resolution, orientation control of microphase-separated domains, etch selectivity, rapid and mild annealing, and compatibility with manufacturing for developing suitable BCPs. Here, we describe recent works regarding orientation control of the domains in block copolymer thin films including a solvent annealing method, a top-coat method, and an approach from BCP molecular design. The strategy of a new design for BCPs targeted for sub-10-nm-wide lines, which are able to form perpendicularly oriented lamellar structures in thin films is described. The designed BCPs provide a good balance in the surface free energies between the blocks, thereby leading to the perpendicular orientation. Moreover, this orientation can be completed in only one minute thermal annealing in an air atmosphere. Oxygen plasma etching for the thin films results in the achievement of a line width of sub-10 nm. Keywords: Block Copolymer Lithography / Self-Assembly / Perpendicular Orientation / Microphase-Separated Domains / Thin Film / Lamellae / Molecular Design |
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