Synthesis and stabilization studies of block copolymer dispersants for water based paints used in the porcelain industry

Polymeric pigment dispersants are the block copolymers which are characterized by their stable chemical structure as they are having selective pigment affinic groups and soluble polymeric chains. Depending on the paint system, different mechanism for pigment stabilization of pigment exist. While electrical stabilization is dominant in water-based systems, steric stabilization is dominant in solvent-based systems. In water-based systems, dispersing agents must meet certain requirements, such as allowing rapid wetting of the pigment surface, as well as helping to stabilize the pigment particles and preventing the pigment particles from re-agglomerating for long periods under storage conditions. In this thesis, firstly, single-ended (PEG-Br) and double-ended (Br-PEG-Br) macroinitiators were synthesized using poly(ethylene glycol) (PEG). As a preliminary experiment, using these macroinitiators, copolymers containing poly(methyl methacrylate) (PMMA) and poly(methacrylic acid) (PMAA) blocks at their ends were synthesized by atom transfer radical polymerization (ATRP). It was investigated whether these polymers could be used as dipersants in water-based paints, especially those used in the porcelain sector and which often experience sedimentation problems. For this purpose, these polymers were added to the water-based paint called Aura Dusk (ADK) used in the industry at different ratios and their effects on the sedimentation behavior were examined. While no precipitation was observed with the addition of MPEG-b-PMMA diblock copolymer, precipitation was observed in the paint with the addition of MPEG-b-PMMA-b-PMAA and PMMA-b-PEG-b-PMMA triblock copolymers. In line with these results, MPEG-b-PMMA diblock copolymers were synthesized with three different PMMA block lengths (1:30, 1:60, 1:120). Number average molecular weights (Mn) and molecular weight distributions (PDI) of all polymers were determined by gel permeation chromatography (GPC). Aura Dusk (ADK) and Aura Passion (APS) paints were used in the application studies. When all results were examined, it was seen that the hydrophobic and hydrophilic blocks in the polymers must be present in the right ratios to ensure stabilization. The hydrophobic PMMA group adsorbs onto the pigment surface, while the hydrophilic MPEG group directs itself towards water, preventing the particles from approaching each other, thus providing steric stabilization.