Influence of β-cyclodextrin on morphologies and chemical, thermal, and mechanical properties of non-chain extended polyurethane elastomers

A series of polyurethane elastomers (PUEs) were synthesized from an aromatic diisocyanate (4,4′-diphenylmethane diisocyanate (MDI)), a polyether polyol (polytetramethylene glycol; molecular weight: 1000 Da (PTMG1000)), and using β-cyclodextrin (β-CD) as the cross-linker. In this study, we investigated the effects of the addition of β-CD on the morphologies and chemical, thermal, and mechanical properties. The introduction of β-CD in the main chain of PUEs was verified using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and swelling test. The morphology was analyzed through SEM and confocal laser scanning microscopy (CLSM). The results show that the PUEs containing β-CD units exhibited an incompatible microstructure that was improved by the addition of β-CD. The tensile strength of PUEs decreased with the addition of β-CD; however, the elasticity was maintained for <5 % β-CD content. The dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were used to prove the existence of a chemically cross-linked structure and evaluate the thermal stability of PUEs having different β-CD content.