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Novel gas sensor from polymer‐grafted carbon black: Vapor response of electric resistance of conducting composites prepared from poly(ethylene‐ block ‐ethylene oxide)‐grafted carbon black
Author(s) -
Chen Jinhua,
Tsubokawa Norio
Publication year - 2000
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/1097-4628(20000912)77:11<2437::aid-app12>3.0.co;2-f
Subject(s) - carbon black , ethylene oxide , materials science , solvent , dichloromethane , polymer chemistry , composite number , composite material , oxide , tetrahydrofuran , copolymer , ethylene , chemical engineering , polymer , chemistry , organic chemistry , catalysis , natural rubber , engineering , metallurgy
A crystalline block copolymer of poly(ethylene‐ block ‐ethylene oxide) (PE‐ b ‐PEO) was successfully grafted onto a carbon black surface by direct condensation of its terminal hydroxyl groups with carboxyl groups on the surface using N , N ′‐dicyclohexylcarbodiimide as a condensing agent. The electric resistance of the composite from PE‐ b ‐PEO (PEO content is above 50 wt %)‐grafted carbon black drastically increased to 10 4 –10 6 times of the initial resistance in a vapor of dichloromethane, chloroform, tetrahydrofuran, and carbon tetrachloride, which are good solvents for PE‐ b ‐PEO, and returned immediately to the initial resistance when the composite was transferred in dry air. However, the change of the electric resistance of these composites was less than one‐tenth in a poor solvent vapor at the same condition. The response of the electric resistance was reproducible and stable even after exposure to a good solvent vapor and dry air with 30 cycles or exposure to the vapor over 24 h. The effect of PEO content on the vapor response was also investigated. The composite from PE‐ b ‐PEO‐grafted carbon black responded to the low vapor concentration with a linear relationship between the electric resistance and the concentration of the vapor in dry air. This indicates that the composite can be applied as a novel gas sensor. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2437–2447, 2000