PMMA‐grafted dextran glycopolymers by atom transfer radical polymerization

Abstract

The four‐step synthesis of amphiphilic glycopolymers associating dextran as backbone and poly(methyl methacrylate) (PMMA) as grafts is reported, using the “grafting from” strategy. In the first step, the dextran OH functions were partially acetylated. The second step consisted in linking initiator groups by reaction of 2‐bromoisobutyryl bromide (BiBB) with the unprotected OH functions. Third, the atom transfer radical polymerization (ATRP) of methyl methacrylate was carried out in DMSO from the resulting dextran derivative used as a macroinitiator. Finally, the cleavage of the acetate groups led to the expected glycopolymers. Careful attention was given both to the copolymer structure and the control of polymerization. PMMA grafts were analyzed by SEC‐MALLS after their deliberate cleavage from the backbone to evidence a controlled polymerization. Moreover, the mildness of the final deprotection conditions was proved to ensure acetate cleavage without either degrading dextran backbone and PMMA grafts or cleaving grafts from dextran backbone. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7606–7620, 2008

Controlled synthesis of new amphiphilic glycopolymers with liquid crystal grafts

“…The synthesis of DexAc τAc Br τBr macroinitiators has been realized within two steps as previously described . Briefly, native dextran has been first hydrophobized by a partial acetylation and then by an introduction of ATRP initiator groups.…”

“…The acetylation yield ( τ Ac ) and initiator groups yield ( τ Br ) were defined by the number of acetate and initiator groups per 100 initial OH functions of dextran, respectively. τ Ac and τ Br were estimated from 1 H NMR spectra in DMSO‐ d 6 using eqs and , respectively . A acetyl H is the area of acetyl protons (around 2 ppm) and A 4.4→5.7 corresponds globally to four protons per glucosidic unit, whatever the acetylation yield.…”

Novel Glycopolymer Brushes via ATRP: 1. Synthesis and Characterization

“…The molar masses obtained from SEC analysis using refractive index detection relative to PMMA standards are just apparent ones 7, 57. It is known that the hydrodynamic volume of branched polymers decreases and therefore branched polymers elute later during SEC analysis as compared to their linear analogues 57–59. In order to obtain a more accurate estimation of the true molar mass and dispersity of the glycopolymer brushes, SEC analysis with a MALLS detector was performed in N , N ‐dimethylacetamide.…”

Modification of Polysaccharides Through Controlled/Living Radical Polymerization Grafting—Towards the Generation of High Performance Hybrids

“…Another widespread approach to obviate these solubility issues consists in partially converting the abundant hydroxyl functions located on the polysaccharide precursors into alkoxyl or acetate groups. Acetylated dextran30 and starch31 backbones have been described as starting materials for the generation of polysaccharide‐ g ‐PMMA copolymers. Cellulose ether and ester derivatives, i.e., HPC, cellulose diacetate (CDA), methyl or ethyl cellulose (MC, EC) have also been extensively investigated as precursors for the preparation of a large range of hybrid graft copolymers by ATRP 32–40.…”