Effect of the cyclic structure content on aliphatic polycarbonate-based polyurethane

Abstract

Aliphatic polycarbonate-based polyurethanes were successfully synthesized using two aliphatic polycarbonate polyols and hexamethylene diisocyanate (HDI) with 1,4-butanediol (1,4-BD) as the chain extender. One of the aliphatic polycarbonate polyols, named PBC-diol, was prepared from dimethyl carbonate (DMC) and 1,4-BD, while the other, named PCHC-diol, was derived by reacting DMC with 1,4-cyclohexanedimethanol (CHDM). The results of the thermogravimetric analysis (TGA) indicated that the cyclic structure improved the thermal stability of the polyurethanes. In addition, the differential scanning calorimetry (DSC) curves showed that the cyclic structure increased the glass transition temperature (Tg) of the polyurethanes but slowed their crystallization. Furthermore, the mechanical properties of the polyurethanes with different cyclic structure contents were analyzed using Instron. Although the elongation at break decreased, the tensile strength increased from 32.6 to 844.0 MPa when the PBC-diol was replaced with PCHC-diol in the polyurethanes. Finally, Fourier transform infrared (FTIR) analysis was conducted to investigate the formation of hydrogen bonds. The relationship between the hydrogen bonds and cyclic structure content was also shown in this study. A series of aliphatic polycarbonate-based polyurethanes with different content of cyclic structure was synthesized. There were more hydrogen bonds between soft and hard segments formed as the content of cyclic units increased. The mechanical and thermal properties of the environment-friendly polycarbonate-based polyurethanes can be enhanced and controlled by varying the content of the cycloaliphatic structures. These polyurethanes can be considered as high potential materials that can be used in different applications in the future.