Fabricated coordinate and ionic bonds in chemically cross-linked ethylene acrylic elastomer for high-performing elastomers

Covalent bond cross-link networks endow rubber with unique resiliency enabling it to be widely used as a series of irreplaceable materials in modern life. However, the balance between rigidity and toughness, which is highly desired with the growing demand for high-performance rubber, remains a significant challenge for covalent bond networks. In this study, magnesium oxide (MgO) was filled in an ethylene acrylic elastomer (AEM) to construct both ionic cluster and coordinate bonds within the framework of a covalent cross-link network, which significantly improved the properties of AEM. The MgO-filled AEM was measured through Fourier transform infrared spectroscopy and thermogravimetric analysis, using a universal testing machine, dynamic mechanical thermal analyzer, and rubber process analyzer. As the multi-bond network was successfully constructed, the tensile strength was enhanced by almost 10 times, and unexpected dynamic properties were exhibited with a higher elastic modulus (rigidity) attributed to ionic clusters and a higher loss factor (toughness) attributed to the coordinate bonds. With the efficient enhancement of the mechanical properties, the improved toughness can dissipate energy to preserve the integrity of rubber under the application of an external mechanical force.