Amine-functionalized fibrous sepiolite and graphene oxide in situ self-assembled hybrid network for reinforcement of natural rubber composite

Efficient fabrication of graphene oxide (GO) network in rubber composites is critical for enhancing its mechanical properties. Herein, the surface of fibrous sepiolite is modified with amino-silane to form amine-functionalized fibrous sepiolite (afSep), then the segregated networks of GO and afSep hybrid sheets in natural rubber (NR) latex can be self-assembled by the electrostatic attraction between the protonated amine groups of afSep and the carboxyl groups/epoxy groups of GO, thereby casting and drying at room temperature to form GO-afSep/NR composite. When the hybrid network is assembled with 0.2 phr (per hundred parts of rubber) GO and 0.4 phr afSep in un-crosslinked NR composite, the tensile strength and elongation at break improve by 33.9% and 4.8% compared with un-crosslinked GO/NR composite, respectively, which is attributed to the segregated network of the afSep fibers attached to the basal plane of GO sheets in NR composite.