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Journal Articles Polymer Year : 2001

Partial or total silylation of dextran with hexamethyldisilazane

Abstract

The silylation reaction of dextran with 1,1,1,3,3,3-hexamethyldisilazane (HMDS) in DMSO was studied as the ®rst step of the synthesis of new amphiphilic polyester-grafted dextrans. According to the experimental conditions, i.e. dextran molar weight, medium temperature and reaction time, HMDS/OH ratio, addition of a catalyst and co-solvent, partially or totally silylated dextrans were recovered. The highest silylation yields were obtained with the lowest molecular weight dextrans. The increase in temperature medium and/or reaction time, the presence of catalyst or co-solvent favored the protection yield. Whatever the dextran used, complete silylation of the polysaccharide chain could be achieved by adequate selection of the experimental conditions. The thermal properties of resulting silylated polysaccharides were investigated by temperature modulated DSC. It was observed that T g values of partially silylated dextran were maintained between 120 and 140 8C, independently of the dextran molecular weight. Interestingly, DMSO proved to behave as an ef®cient plasticizer of (partially) silylated dextrans. The partially silylated dextrans were ef®ciently used as multifunctional macroinitiators for the controlled ring-opening polymerization (ROP) of lactone. The ROP was then promoted from the remaining hydroxyl groups in the presence of tin or aluminium activator. After polymerization and ultimate deprotection of the silylated dextran backbone, amphiphilic polyester-grafted dextrans were readily recovered. q

Dates and versions

hal-02945698 , version 1 (22-09-2020)

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Cécile Nouvel, Isabelle Ydens, Philippe Degée, Philippe Dubois, Edith Dellacherie, et al.. Partial or total silylation of dextran with hexamethyldisilazane. Polymer, 2001, 43 (6), pp.1735-1743. ⟨10.1016/S0032-3861(01)00778-9⟩. ⟨hal-02945698⟩
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