Poly(Ethylene Glycol)/β-Cyclodextrin Pseudorotaxane Complexes as Sustainable Dispersing and Retarding Materials in a Cement-Based Mortar

Pseudorotaxane complexes between β-CD and mPEG derivatives bearing a carboxylic acid function (mPEG–COOH) were synthesized and investigated for their dispersing properties in a cement-based mortar. The formation of mPEG–COOH derivatives and their pseudorotaxanes was investigated by 1D nuclear magnetic resonance, diffusion ordered spectroscopy, and thermogravimetric analysis experiments. Mortar tests clearly indicate that mPEG–COOH@β-CD-interpenetrated supramolecules show excellent dispersing abilities. In addition, the supramolecular complexes show a retarding effect, analogously to other known β-CD-based superplasticizers in which the β-CD is covalently grafted on a polymeric backbone.