Ernst Eckstein

Design of new pigment dispersants by controlled radical polymerization

Abstract Polymeric pigment dispersants are essential for the formulation of high solids and waterborne coatings. New technologies for controlled polymerization play an important role for the development of improved pigment dispersants. In the last years, big progress has been made especially on nitroxide-mediated controlled free radical polymerization, as well as on atom transfer radical polymerization (ATRP). Both techniques overcome limitations of classical polymerization methods and provide an efficient route to functional copolymers with exact control of molecular weight distribution and molecular architecture. New developed nitroxide polymerization regulators as well as ATRP were used for the synthesis of acrylic block copolymers, which are a promising class of dispersants, especially for difficult to disperse organic pigaments. On the example of selected pigments, it was investigated how structural parameters like chemical composition, block length and molecular weight influence the dispersant performance. Special attention will be given to the rheological behavior of pigment concentrates.