Efficient dispersion of TiO2 using tailor made poly(acrylic acid) − based block copolymers, and its incorporation in water based paint formulation

Abstract

Abstract 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 TiO 2 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 ( 1 H NMR). The success of the polymeric dispersant adsorption onto TiO 2 particles was confirmed by a clear change on zeta potential (ζ) values (from −1.28 mV of TiO 2 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 TiO 2 and in a common water-based paint formulation. After paint application, the successful dispersion of TiO 2 particles using the amphiphilic block copolymers of PAA 24 - b -P4VP 57 , PAA 72 - b -P4VP 82 , PAA 24 - b -PDMAEMA 16 and PAA 24 - b -PDMAEMA 24 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 TiO 2 dispersants in paint formulations.