Preparation and Properties of Carboxylated Styrene-Butadiene/Carboxylated Cellulose Nanocrystal Composites with Self-healing Properties

The self-healing properties of rubber products can be given by the introduction of dynamic crosslinking bonds. In this work, carboxylated cellulose nanocrystals (CCA) and zinc oxide (ZnO) were selected as fillers. Carboxylated styrene-butadiene rubber (XSBR) composites (X/C/Z) with dual dynamic crosslinking networks were constructed by constructing ionic bonds between Zn2+ of ZnO and the carboxyl groups of XSBR and CCA, as well as hydrogen bonds between the carboxyl groups of CCA and XSBR. The Fourier transform infrared spectroscopy (FTIR) results confirmed the existence of dual dynamic crosslinking networks in X/C/Z composites. Compared with XSBR/CCA and XSBR/ZnO composites, the dual dynamic crosslinking networks and the synergistic reinforcement of CCA and ZnO endow X/C/Z composites with more excellent physical and mechanical properties. Fixed the CCA content at 5 wt%, the crosslinking density of X/C/Z composites increased with the increase of ZnO content. The tensile strength of the composites also showed an increasing trend, while the elongation at break gradually decreased. Meanwhile, the increase of ZnO content provided more Zn2+ that can complex with the carboxyl groups of XSBR and CCA to form ionic bonds. As a result, the self-healing ability of the composites were enhanced greatly. In this study, using ZnO and CCA as reinforcing/cross-linking fillers, carboxylated styrene-butadiene rubber self-healing composites with excellent properties were prepared by a simple and convenient method, which provided a way for the development of self-healing composites. [GRAPHICS] .