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Material design of high-performance polymers by applied rheology
Rheology - the new science of deformation and flow for a material showing complicated mechanical responses - is necessary in order to develop advanced polymeric materials. Our laboratory is carrying out material design of functional and high-performance polymers based on the rheological approach to create novel displays, next-generation automobile parts, eco-friendly materials including biomass-based plastics, and so on. Moreover, innovation of polymer processing is also studied with our industrial partners, considering trouble-shooting of actual processing operations Our research activities are outlined below.

Staff
Director
Masayuki Yamaguchi, Dr. Professor
Head, Materials Chemistry Area
[E-mail]   m_yama at jaist.ac.jp
[Phone]   +81-761-51-1621
[Facsimile]   +81-761-51-1149
[Degrees]   B.E. (1987), M.E. (1989), Doctor degree (1999) from Kyoto University
[Business career]   TOSOH Corporation (1989-2005)
* New Jersey Institute of Technology / Polymer Processing Institute (2000-2002)

Reseach projects
[1] Research and Development of high-performance polymers and functional polymers
Material design of high-performance optical films is performed by means of rheological modification. The target polymers include newly developed polymers, biomass-based polymers, and conventional polymers.

Optical functional polymers
(1) Birefringence control
(2) Thermochromic films
(3) Transparent crystalline plastics and polymer blends with phase separation
(4) Modulus enhancement for plastic glass
(5) Improvement of heat distorsion temperature by low-molecular-weight compounds for plastic glass

Orientation control of polymer products
(1) Transversal orientation to the flow direction
(2) Design of super-tough plastics having plywood structure
(3) Control of orientation birefringence
(4) Development of super fiber with high level of orientation

Material design with additive
(1) All season tire using interphase transfer of plasticizer
(2) Transparent polypropylene, super-tough polypropylene by addition of nucleating agent
(3) Enhancement of glass transition temperature for glassy plastics
(4) Improvement of anti-scratch property for polypropylene and polycarbonate
(5) Control of optical retardation by using orientation correlation with additive
Material design of conductive polymers with carbon nanotubes
We are developing a conductive plastic by addition of carbon nanofillers. Advanced techniques to localize conductive fillers in polymer nanocomposites are established. Because only a tiny amount of conductive fillers is required for electro-conductivety, the cost-performance should be improved greatly.
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[2] Study on Polymer Processing
Rheology provides fundamental information on polymer processing. Based on the experiences and basic information on polymer sciences, extensive study on various processing operations such as foaming, injection-molding and extrusion are carried out considering properties of final products. The obtained results provide new ideas for material design of high-performance or functional polymers.

Extrusion coating of polyolefins
Extrusion coating is performed at considerably high temperature to enhance the adhesive property with a substrate. We are proposing a material design for extrusion coating considering the rheological change during the processing, such as shear modification and thermal degradation.

Foaming of linear polymers
Because of the weak melt elasticity, foaming of linear polymers, such as polypropylene (PP) and poly(lactic acid) PLA, is difficult in general in spite of the intensive needs in various applications such as automobile parts and food tray. We are proposing various techniques to enhance the strain-hardening in elongational viscosity, one of the most important elastic natures for foaming, such as critical gel method, blending of flexible nanofibers, and incorporation of long-chain branches. The final target of this project is to obtain foamable PP and PLA without crosslinking procedure, which enables to material recycling.

Effect of applied flow history on the rheological properties and processability
Rheological properties and thus the processability of long-chain branched polymers are sensitive to the processing history, because long-chain branches align to the flow direction under shear dominant flow. Considering the phenomenon, called "shear modification", screw geometry and material recycling have to be decided. This project deals with the unique phenomenon from the view points of molecular rheology. Further, industrial application is proposed.
Fig.1 Growth curves of uniaxial elongational viscosities at various strain rates for autoclave LDPE having different processing histories.

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[3] Rheological Characterization of Soft Materials
Rheological information is necessary for the development of soft materials, including cosmetics, foods, and biomaterials. We are developing a new method to evaluate functional soft materials and discussing the relation with the feeling of consumers. This research is indispensable for the material design in industry.
Rheological properties of cosmetic foam
Rheological properties of functional foams such as facial cream and body soap are evaluated by newly developed methods. The basic characterization of acqueous foams is also carried out to correlate with the rheological properties. As compared with user's feeling, material design of a new foam product is proposed.
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  Other Information
  Presentation at International Conferences

  Equipment in Yamaguchi Lab.

  Current members

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YAMAGUCHI Masayuki Laboratoty
School of Materials Science, JAPAN ADVANCED INSTITUTE OF SCIENCE AND TECHNOLOGY
Address: 1-1 Asahidai, Nomi, Ishikawa 923-1292 Japan
phone:+81-761-51-1621 facsimile:+81-761-51-1149 E-mail:m_yama@jaist.ac.jp