Synthesis of polymeric dispersants from renewable DCO fatty acid and their multifunctional behavior in waterborne flat paint

Copolymers containing 50% dehydrated castor oil fatty acids (DCOFA) derived from renewable resources, were synthesized via free radical solvents less polymerization with maleic anhydride, styrene, and butyl acrylate. The copolymer was crosslinked further with polyethylene glycol 400 (PEG 400) to increase its molecular weight. The copolymers with and without crosslinking were then neutralized with sodium hydroxide to prepare polymeric dispersants DFCD1 and DFCD2 respectively in aqueous medium. It was observed via surface-tension measurement that both DFCD1 and DFCD2 transfer to the air–water interface before forming any aggregates, and the ease of forming the aggregates is in the order of DFCD1 > DFCD2. The efficacy of these dispersants was examined in the dispersion of the titanium dioxide pigment and conventional extenders like calcite, talc, and china clay using flow point and zeta potential measurements. The results reveal that DFCD2 improved the dispersing ability for the pigment and extenders studied. The performance of these polymeric dispersants was also studied and compared in waterborne flat paint as a rheology modifier and pigment-dispersing agent. The paint rheology profile and dE data indicate the superior performance of the paint containing dispersant DFCD2. When used in combination with conventional styrene-acrylic latex, DFCD1 and DFCD2 reduced the minimum film-forming temperature (MFFT) of the polymer latex.