Sodium alginate crosslinked oxidized natural rubber supramolecular network with rapid self-healing at room temperature and improved mechanical properties

Abstract

Rubbers with dynamic covalent bonds generally require external stimuli to trigger the healing process, e.g. high temperature, which caused inconvenience to utilize. In contrast, rubbers based on noncovalent supramolecular networks can be spontaneously repaired under mild conditions, but usually exhibit kPa level on the mechanical properties. In this paper, a rapid self-healing composite film with considerable mechanical properties was developed based on sodium alginate (SA) crosslinked oxidized natural rubber (oNR) supramolecular hydrogen bonding network. The NR latex was firstly modified to equip oxygen-containing polar groups and then blended with SA solution. After film-formation, regenerated SA formed a frame-like network and simultaneously participated in formation of a reversible supramolecular network via hydrogen bonding with rubber matrix. The composite film with 20 phr SA showed improved tensile strength of 6.5 MPa, meanwhile, its self-healing efficiency could reach 60% after self-healing 2 min and reach 80% after 10 min at room temperature.