Preparing hydrophilic styrenic block copolymers: coupling polyetherdiamine with carboxylated polystyrene-block-polybutadiene

摘要

Styrenic block copolymers such as polystyrene-block-polybutadiene (SB) have been widely used as thermoplastic elastomers. Nevertheless the lack of polarity and hydrophilicity has prevented them from being used in certain applications such as stabilizers for dispersions and emulsions, compatibilizers for polymer blends, and modifiers for surface characteristics. An effective method of increasing their hydrophilicity was to incorporate polyoxyalkylene into the hydrophobic backbones utilizing the hydrophilic and mobile nature of polyoxyalkylene. Although a hydrophilic polyoxyalkylene segment could be formed in-situ by polymerizing ethylene oxide or propylene oxide onto the living end of SB block copolymers anionically, a well-conducted anionic polymerization of such alkylene oxides usually required very stringent reaction conditions. Therefore it has been attempted in this work to make a hydrophilic, polyoxyalkylene-containing, SB copolymer by coupling a carboxylated SB (SB-COOH) with a commercially available polyetherdiamine (Jeffamine ED2003). This polymer was characterized and the its hydrophilicity was evaluated. Furthermore, rheological and dynamic mechanical studies were made to examine the effect of the hydrophilic polyoxyethylene-co-polyoxypropylene segment on the domain structure of the polymer.