2007 Fiscal Year Final Research Report Summary
Invention of Electromagnetic-wave Absorbing Composites Utilizing Bicontinuous Polymer Structure and Percolation of Nano-carbons
| Project/Area Number |
18350119
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Polymer/Textile materials
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| Research Institution | Kyoto Institute of Technology |
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Principal Investigator |
TAKAHASHI Masaoki Kyoto Institute of Technology, Graduate School of Science and Technology, Professor (50115870)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Katsufumi Kyoto Institute of Technology, Graduate School of Science and Technology, Associate Professor (50207081)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Nano-carbon / Percolation / Bicontinuous structure / Polymer blend / Electromagnetic-wave absorbance / Electrical conductivity / Dielectric property / Composite |
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| Research Abstract |
The objective of the present study is to invent electromagnetic-wave absorbing composites which show superior absorptive power in GHz band Network of nano-carbon particles is formed, utilizing phase separated structure of polymer blends and preferred strand length of cross-linked network. Electrical conductivity and electromagnetic-wave absorbance are extremely enhanced by formation of the network. More than 95% absorbance of electromagnetic-wave in GHz band is achieved for the following composites at concentration slightly higher than (or equal to) each threshold.
1) Aggregated clusters of acetylene black (AB) takes various shapes, resulting in non-fractal structure near the threshold. By long time annealing in poly (methyl methacrylate), the threshold becomes as low as 22vo1%.
2) Dispersion control of AB can be made utilizing silicon rubber with average network strand length comparable with diameter of AB.
3) In bicontiuous structure of high density polyethylene (HDPE)/polyjappylene (PP) blend, selective location of vapor grown carbon fibers (VGCF) in HDPE phase results in decrease of threshold and enhancement of electrical conductivity compared with those in HDPE or PP.
4) With addition of very small amount of HDPE to PMMA matrix, HDPE chains adsorb onto rough surface of VGCF ends, contributing to connectivity of VGCF and thus to enhancement of electrical conductivity and electromagnetic wave absorbance.
The apparent dielectric constant and loss factor increased with time during the electrical orientation process of VGCF suspended in reactive silicone.
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