Study on synthesis of poly(N-isopropylacrylamide) grafted carbon black and temperature-dependence conductivity of grafted carbon black/epoxy composites

Abstract

Carbon black nanoparticle grafted with poly(N-isopropylacrylamide) (CB-g-PNIPAAm) was synthesized by surface-initiated atom transfer radical polymerization (SI-ATRP). The temperature-responsive behavior of CB-g-PNIPAAm was proved by temperature-variable 1H NMR. A temperature-dependent conductive composite was prepared by blending CB-g-PNIPAAm with epoxy resin. The relationship between temperature and resistivity of the composite was studied: the composite exhibited a negative temperature coefficient (NTC) phenomenon. Possible mechanism for the NTC phenomenon was suggested. The results showed that resultant composites can be used in intelligent temperature-switching. © 2008 Wiley Periodicals, Inc.