Synthesis of acrylic copolymers consisting of multiple amine pendants for dispersing pigment.

A class of acrylic copolymers with narrow molecular weight distribution from butyl methacrylate and glycidyl methacrylate comonomers via atom transfer radical polymerization was synthesized. Various types of polarities including hydroxyl-amines, glycols, and carboxylic acids were then grafted onto the oxirane side groups. The resultant comb-like copolymers with different polar pendants were tested for homogenizing a representative Yellow pigment in 1,6-hexanediol diacrylate medium. Specifically, the polyacrylates with 1,3-diamine pendants (7-10 multiplicity on each polymer strain) enabled to homogeneously disperse the pigment than the analogous copolymers with hydroxyl or carboxylic acid groups. Ultimately, the pigment dispersion with an average size of ca. 20 nm in diameter, high transmittance and low viscosity was achieved. Furthermore, the pigment dispersion was allowed to UV-cure into a film, and for the first time, the primary structures of the pigment particles (ca. 50 nm in diameter) were observed by transmission electronic microscope.