Cross‐linking of γ‐Cyclodextrin Using Non‐toxic Polyethylene Glycol Spacer Units

Abstract

The crystalline cyclic oligosaccharide γ‐cyclodextrin (γCD) is a natural, non‐toxic and biodegradable precursor that can be used to prepare innovative polymers. We cross‐linked γCD with variable quantities of non‐toxic polyethylene glycol diglycidyl ether (PEGDGE) in aqueous NaOH to form 3D structures with tunable physicochemical properties. Mixtures with a 5 : 1 PEGDGE:γCD molar ratio produced a cross‐linked material that was soluble in water and organic solvents, underwent glass transition at −23 °C. The properties of this material were further modified by additional curing with PEGDGE or nitration reaction. Curing produced an insoluble polymeric material with excellent swelling abilities (200 % in water) and decreased glass transition temperature to −37 °C. The nitrated cross‐linked γCD was soluble in common organic solvents and underwent glass transition at +19 °C, achieving thermal stability below 190 °C. These novel γCD polymers are promising materials for applications in the pharmaceutical and food industries and environmental remediation.