Novel block copolymers of 2-vinylpyridine and eta-caprolactone: synthesis and characterization

Novel block copolymers based on 2-vinylpyridine (2VP) and -caprolactone (CL) have been synthesized via sequential anionic polymerization in tetrahydrofuran (THF). These block copolymers are expected to be promising pigment dispersing agents for TiO2 in e. g. polyester powder coatings. Initiation of CL by the living P2VP polymer occurred instantaneously and without side reactions. Intramolecular transesterification reactions were not observed either. However, part of the living chains was deactivated immediately after the addition of CL, which yielded bimodal molecular weight distributions. This could be attributed to strong aggregation of the alkoxide chain ends. Addition of LiCl to the polymerization mixture prevented aggregation and resulted in well-defined block copolymers. The block copolymers have been characterized with SEC, NMR and IR.