Topologically linked branch polymers from mono-amino-cyclodextrins and polyethylene glycol dicarboxylic acid

Abstract

Topologically linked branch polymers were prepared by condensation of mono-6-deoxy-mono-6-amino cyclodextrin (NH2αCD, NH 2βSCD, and NH2γCD) with polyethylene glycol dicarboxylic acid (PEGdiCOOH). Some NH2CD molecules and PEGdiCOOH chains form inclusion complexes prior to condensation reaction. Since these complexes act as multifunctional monomers, the condensation product contains topologically linked branch polymers, in which CD rings act both as a topological cross link and as a capping site to prevent dethreading of CD molecules from PEG chains. The formation of a dumbbell shape molecule of CD-PEG-CD was confirmed by NMR analysis. The production of topologically linked branch polymers was confirmed by the multi-modality of size exclusion chromatogram (SEC). The curve resolution of the chromatogram allowed us to estimate the fractions of topologically linked polymers in the products and of the CD molecules threaded on PEG to form topological link. These fractions increase in order of γCD < αCD < βCD. © 2008 The Society of Polymer Science.