Styrene-tert-Butyl Methacrylate and Styrene-Methacrylic Acid Block Copolymers:Synthesis and Characterization

摘要

Sequential living anionic polymerization techniques were used for synthesis ofblock copolymers of styrene and tert-butyl methacrylate. Cumylpotassium and naphthalene-potassium complexes served as initiators for diblock and triblock copolymers, respectively. The synthetic procedure and apparatus are described in detail. The copolymers as well as their polystyrene blocks had unimodal distribution of molecular weights. Their polydispersity Mw/Mn was typically less than 1. 1. Procedures were also developed for fluorescence labeling of the copolymers at the methacrylate end of the molecule by dansyl or anthryl moieties and at the beginning or end of the polystyrene block by naphthyl moieties. In the next synthetic step, the tert-butyl ester groups were hydrolyzed off, leaving block copolymers of styrene and methacrylic acid. The copolymers were characterized by gel permeation chromatography, light scattering, viscometry, proton NMR, thermogravimetric analysis, and differential scanning calorimetry.