A novel gas sensor from crystalline polymer-grafted carbon black: responsibility of electric resistance of composite from crystalline polymer-graftedcarbon black against solvent vapor

Crystalline polymers, such as poly(epsilon-caprolactone) (PCL), poly(ethyle ne adipate) (PEA), and polyethylene (PE), were successfully grafted onto ca rbon black surface by direct condensation of terminal groups of these polym ers with carboxyl groups on the surface using N,N'-dicyclohexylcarbodiimide as a condensing agent. The electric resistance of a composite prepared fro m these crystalline polymer-grafted carbon black drastically increased to 1 0(4)-10(5) times of initial resistance in good solvent vapor of grafted pol ymer and returned to initial resistance when it was transferred into dry ai r. However, the change of electric resistance of the composite hardly obser ved in poor solvent vapor. These results suggest that these composite can b e applied as a novel gas sensor.