Polymer/C.I. Pigment Red 170 hybrid latexes prepared by RAFT-mediated surfactant-free emulsion polymerization

By using organic pigment-based ink-jet inks, the digital ink-jet printing of textiles is one kind of environmentally friendly technology for cleaner dyeing. Due to the shortcomings of easy agglomeration and poor water dispersion stability of organic nanoparticles , however, the encapsulation and dispersion of organic pigment nanoparticles are also hot and difficult research problems. In this work, we report the reversible addition-fragmentation chain transfer (RAFT) polymerization technology was used to synthesize random copolymer of 2-(dimethylamino) ethyl methacrylate (DMAEMA), poly(ethylene glycol) methyl ether methacrylate (PEGA), and methyl methacrylate (MMA) or butyl acrylate (BA) with a trithiocarbonate reactive end-group. These cationic macromolecular RAFT agents (macro-RAFT) with a pH of 5 were subsequently adsorbed at the surface of size-monodisperse colloidal Pigment Red 170 particles. The absorbed macro-RAFT agents were considered to be the living points to mediate the RAFT polymerization of monomers (MMA and BA) by starved feed emulsion polymerization . TEM results shown that the resulting hybrid latexes synthesized in presence of the tri-copolymer macro-RAFT agents resulted in the formation of individually encapsulated pigment particles. In addition, the dynamic light scattering (DLS), zeta potential and stability tests found that the macro-RAFT agent participated in the growing latex stabilization which is the key to obtaining the stable and uniform core-shell hybrid latex. More importantly, the preparation of film-forming copolymer/pigment hybrid latex in this study shown that the high potential of the P(DMAEMA- co -PEGA- co -MMA or BA) macro-RAFT agent for the development of polymer-pigment hybrid latexes which has good application properties.