Synthesis of amphiphilic poly(methyl metha-crylate)-block-poly(methacrylic acid) diblock copolymers by atom transfer radical polymerization

摘要

Atom transfer radical polymerization (ATRP) of l-(butoxy)ethyl methacrylate (BEMA) was carried out using CuBr/2,2'-bipyridyl complex as catalyst and 2-bromo-2-methyl-propionic acid ester as initiator.The number average molecular weight of the obtained polymers increased with monomer conversion,and molecular weight distributions were unimodal throughout the reaction and shifted toward higher molecular weights.Using poly(methyl methacrylate) (PMMA) with a bromine atom at the chain end,which was prepared by ATRP,as the macro-initiator,a diblock copolymer PMMA-block-poly [l-(butoxy)ethyl methacrylate] (PMMA-b-PBEMA) has been synthesized by means of ATRP of BEMA.The amphiphilic diblock copolymer PMMA-block-poly(methacrylic acid) can be further obtained very easily by hydrolysis of PMMA-b-PBEMA under mild acidic conditions.The molecular weight and the structure of the above-mentioned polymers were characterized with gel permeation chromatography,infrared spectroscopy and nuclear magnetic resonance.