Effect of Structural Flexibility of Hydrogen Bonds on Dynamic mechanical Properties of Crosslinked Polymers

Abstract

Polymers crosslinked with reversible dynamic bonds such as hydrogen bonds show dynamic mechanical functionalities such as self-recovering ability. Here, we aimed to elucidate the effects of the structural flexibility of multiplexed hydrogen bonds (H-bonds) upon the mechanical properties of reversibly crosslinked polymers. We synthesized polybutadiene modified with vicinal diol (VDO), which was flexible and had multiple stable H-bonding modes, and urazole, which was rigid and showed only one binding mode. The mechanical properties of these two polymers were compared.According to the results of the rheological measurements, tensile tests, and cyclic tensile tests, the H-bonds between flexible VDO groups dissociated and reassociated more easily compared to those between rigid urazole groups, contributing to superior dynamic properties such as extensibility and self-recovery ability.