Synthesis of Bimodal Methacrylic Acid Oligomers by Template Polymerization

Abstract

A multivinyl template monomer with 20.4 methacryloyl groups was synthesized with β-cyclodextrin by esterification of hydroxyl groups with methacrylic anhydride. Copper-mediated atom transfer radical polymerization of the template monomer was carried out with methyl 2-bromopropionate, 2,2‘-dipyridyl, and CuBr as an initiator, a ligand, and a catalyst, respectively. The effects of solvent and polymerization temperature on the degree of polymerization in the template monomer were investigated by kinetic analysis of conversion and the molecular weight of methacrylic acid oligomers obtained by hydrolysis of the polymerized products by GPC. Poly(methacrylate) oligomers with 7 and 14 degrees of polymerization were synthesized along the rims of the template monomer-3 by ATRP in a methanol/water mixture (water 10 vol %) at 50 °C. The observed propagation rate constant, k obs, of the methacryloyl group in the methanol/water mixture (water 10 vol %) at 50 °C was 11.3 × 10 -5 /s.