| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1998: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1997: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
To prepare a novel gas sensor against various solvent vapor, the responsibility of electric resistance of inter penetrating network (IPN)-type nano-composite was investigated. In addition, the responsibility of electric resistance of composite from crystalline polymer-grafted carbon black against solute in hexane was also examined.
Crystalline polymers, such as polyethylene (PB), poly(epsilon-caprolactone) (PCL), poly(ethylene glycol) (PEG), and poly(ethylene adipate) (PEA) were successfully grafted onto carbon black surface by direct condensation of terminal hydroxyl groups of these polymers with carboxyl groups on the sufface using N,N'-dicyclohexyl-carbodiimide as a condensing agent. A uniform resistor was readily pre-pared by mixing the the polymer-grafted carbon black with crystalline polymer.
The preparation of inter penetrating network (IPN)-type nano-composite of PE-grafted carbon black with PCL was achieved by cationic ring-opening polymerization of CL in the presence of crossli
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nked PB-grafted carbon black. No responsibility of the composite against solvent vapor, however, was observed because of crosslink-ing of matrix polymer.
Although the change of electric resistance of the composite hardly observed in dry hexane, the electric resistance of a nano-composite prepared from crystalline polymer-grafted carbon black drastically increased in hexane containing good solvent of grafted polymer. For example, the electric resistance of composite from PCL-grafted carbon black increased in hexane containing chloroform, tetrahydrofuran, and alcohol, and returned to initial resistance when the composite was transferred in dry hexane.
It was found that the logarithm of electric resistance of the composite is linearly proportional to chloroform concentration in hexane. This indicates that the composite can be also applied as a novel solute sensor and a densitometer.
This is due to a slight change of gaps between carbon black particles by the change of crystalline structure based on the absorption of solute of a good solvent of grafted polymer. Less
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