Controlled grafting of acetylated starch by atom transfer radical polymerization of MMA

Graft copolymers of acetylated starch oligomer (AS) and poly(methyl methacrylate) (PMMA) were polymerized by atom transfer radical polymerization (ATRP). AS was converted to an ATRP macroinitiator by converting a part of the hydroxyl groups of AS to 2-bromoisobutyryl groups. Macroinitiators with varying degrees of substitution for the 2-bromoisobutyryl group were prepared. The polymerizations were conducted using CuBr/BiPy catalyst system, either in bulk or in 1:1 v/v THF solution. They proceeded with first-order kinetics and the molecular weights of the polymers increased linearly with conversion. Graft copolymers with different graft densities and graft lengths were prepared in a controlled manner. The hydrophobicity of these copolymers was studied by contact angle measurements.