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

Abstract

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.

The Influence of the Hydroxyl Type on Crosslinking Process in Cyclodextrin Based Polyurethane Networks

“…A special situation may be encountered for the carbohydrates-based polyurethane crosslinked systems used for, e.g., biomedical applications [ 2 ]. In the particular case of cyclodextrins, the polyols constitute hard segments and also contribute to the phase separation phenomena [ 3 ].…”

Synthesis and Properties of Polyurethane Hydrogel Based on β‐Cyclodextrin Partial Nitrates and Poly(ethylene glycol)

“…As one can observe, in the range of the urea CO absorption band there is a low intensity peak. Therefore, there is almost no urea formation proceeding under these conditions, whereas if the reaction is carried out in DMF medium there is a significant peak of urea band along with the peak of stretching oscillation of urethane's carbonyl band on IR spectra.…”

“…The utilization of CD partial nitrate allowed carrying out PUH synthesis without isolation of the intermediate product – macrodiisocyanate. The use of freshly distilled THF as the solvent made it possible to conduct the reaction in less humid conditions than in techniques described in literature . Furthermore, a much less amount of HMDI was wasted on the side reaction of urea formation (Figure ).…”

“…For instance, the formation of CD‐based polyurethane elastomers (PU) must be conducted in highly hydrophilic media (e.g. dimethylformamide, dimethylsulfoxide) in which it is difficult to minimize the water content . The presence of water brings into action the side reaction of urea formation, which adversely affects the molecular mass of reaction products, their degree of cross‐linking and, accordingly, their properties.…”

Influences of Polyol on the Chemical, Thermal, and Mechanical Properties of Polyurethane Elastomers Crosslinked by &lt;i&gt;β&lt;/i&gt;-Cyclodextrin

“…PUEs containing β-CD may be used for many purposes, such as heat insulation, tremor insulation, and cases for commercial instruments. We recently synthesized PUEs containing β-CD by the prepolymer method [31] [32] [33].…”