Synthesis, Characterization and Thermolysis of Hyperbranched Homo- and Amphiphilic Co-Polymers Prepared Using an Inimer Bearing a Thermolyzable Acylal Group

Abstract

Degradable hyperbranched polymers were synthesized via self-condensing atom transfer radical copolymerization of methyl methacrylate (MMA) with a novel inimer bearing a thermolyzable acylal group. This inimer was 1-(2-bromoisobutyryloxyl)ethyl methacrylate (BIB1EMA) and was synthesized in a one-step reaction between 2-bromoisobutyric acid and vinyl methacrylate at 40% yield. The inimer was subsequently used for the preparation of three degradable hyperbranched homopolymers of MMA (monomer conversion ∼80%) with molecular weights in the range from 36 000 to 51 000 g mol–1 synthesized using initial MMA-to-inimer molar ratios between 25 and 100. The inimer was also used for the preparation of two degradable hyperbranched amphiphilic copolymers of MMA and 2-(dimethylamino)ethyl methacrylate (DMAEMA) with an MMA hydrophobic hyperbranched core and different compositions, 10 and 38 mol % DMAEMA, afforded by changing the relative loadings in the two comonomers. Both hyperbranched amphiphilic copolymers were solubl...