A novel dispersant for preparation of high loading and photosensitive carbon black dispersion

High loading of stable carbon black (CB) dispersion in organic solvent, PGMEA, was prepared by a ball-milling process when using poly(styrene-EHA-HEMA)-block-poly(styrene-EHA-HEMA-DMAEMA) (P(SEH)-b-P(SEHD)) as a dispersant. The P(SEH)-b-P(SEHD) containing P(SEH) as a steric chain and P(SEHD) as an anchoring chain was prepared by TEMPO-mediated polymerization. The tertiary amine group of DMAEMA in P(SEHD) chain could be adsorbed onto CB by the interaction with the carboxylic acid group on surface of CB and the P(SEH) chain could provide sufficiently steric repulsion force to avoid the aggregation of CB. In addition, a photosensitive dispersant, P(SEH)-b-P(SEHD)(C=C), containing the methacrylate double bond side group was also synthesized and was used to prepare stable CB dispersion in PGMEA. The effects of the molecular weight between steric and anchoring chains, the content of tertiary amine, and the amount of methacrylate double bond in the dispersant on the particle size of CB were investigated. Furthermore, the influences of various surface properties of CB, such as specific surface area, content of carboxylic acid group, and size of primary particle, on the particle size of CB in dispersion were also discussed. Finally, the photosensitivity of P(SEH)-b-P(SEHD)(C=C)/CB composite was monitored by a photodifferential scanning calorimeter. (C) 2008 Wiley Periodicals, Inc.