In this work, new amphiphilic diblock copolymers of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and poly(4-vinylpyridine) (P4VP) as anchoring blocks, and poly(acrylic acid) (PAA) as outer block, have been synthetized and evaluated as tailor-made polymeric dispersants of TiO2 particles in aqueous solution. The amphiphilic block copolymers with molecular weight up to 20,000 g/mol were synthetized by atom transfer radical polymerization (ATRP), and the stabilizing effect of the different block segment ratios was studied. These diblock copolymers were fully characterized by size exclusion chromatography (SEC), and nuclear magnetic resonance analysis (1H NMR). The success of the polymeric dispersant adsorption onto TiO2 particles was confirmed by a clear change on zeta potential (ζ) values (from −1.28 mV of TiO2 particles to values higher than 25 mV for the block copolymers dispersions) and by an increase of the hydrodynamic diameter determined by dynamic light scattering (DLS). The influence of different block segment lengths in the obtained copolymers was evaluated in aqueous dispersions of TiO2 and in a common water-based paint formulation. After paint application, the successful dispersion of TiO2 particles using the amphiphilic block copolymers of PAA24–b-P4VP57, PAA72–b-P4VP82, PAA24–b-PDMAEMA16 and PAA24–b-PDMAEMA24 was confirmed by an increase in the gloss (43.8, 41.8, 39.5 and 37.7 g u., respectively), when compared to the commercial reference, Additol VXW 6200 (36.6 g u.). Such features are particularly relevant for the development of polymeric stabilizers to be used as TiO2 dispersants in paint formulations.
Volume 104, March 2017, Pages 34–42