Design and characterization of novel β-cyclodextrin based copolymer materials

Reported herein are the systematic design and characterization of several novel polyurethane (PU) copolymers containing a macrocyclic porogen (β-cyclodextrin; β-CD). These copolymers were synthesized from the reaction between β-CD with different types of diisocyanate linker molecules (e.g., 1,6-hexamethylene diisocyanate (HDI), 4,4′-dicyclohexylmethane diisocyanate (CDI), 4,4′-diphenylmethane diisocyanate (MDI), 1,4-phenylene diisocyanate (PDI) and 1,5-naphthalene diisocyanate (NDI)) at variable synthetic conditions. The copolymers were characterized using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), solid state 13C CP-MAS NMR, 1H/13C solution NMR spectroscopy, thermogravimetric analysis (TGA) and elemental analyses (CHN). The PU copolymers were generally insoluble in water and the optimal preparation of copolymer materials for sorption-based applications is for β-CD/linker synthetic mole ratios from 1:1 to 1:3. The practical upper limit of the crosslink density (∼1:7, β-CD/linker) depends on the steric bulk of the cross linker units.

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► A series of novel macrocycle-based polyurethanes were designed from β-CD and diisocyanate cross linkers with variable molecular structure and tunable physicochemical properties.
► Characterization of the co-monomer composition was achieved using 13C solids and 13C/1H solution NMR spectroscopy, FT-IR spectroscopy, TGA, and CHN elemental analyses.
► Optimal copolymer design was achieved based on an estimated upper limit of the β-CD:linker mole ratio (∼ 1:6) whereas an independent determination of the optimal sorption properties for the co-monomer mole ratio in the range 1:1–1:3 was concluded.
► The results reported herein are anticipated to contribute to the further development of copolymers with improved sorption capacity and molecular recognition properties for a range of sorption-based applications.