Novel CNC/silica hybrid as potential reinforcing filler for natural rubber compounds

This work describes the development of a low-density, renewable, and high reinforcing filler for natural rubber (NR) compounds. The cellulose nanocrystal (CNC)-based hybrid filler was synthesized by decorating the surface of CNCs with silica using a simple and efficient coprecipitation method. The properties of the prepared hybrid were investigated by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, nitrogen physisorption measurements, and Thermogravimetric analysis. Then, the prepared hybrid was incorporated in NR using two different approaches, namely, dry mixing and coprecipitation. The dynamic and tensile mechanical properties of the hybrid/NR compounds were evaluated indicating that: the coprecipitation method was found much more effective for homogeneous dispersion and the CNC/silica hybrid provided quite higher reinforcement to NR than reference silica; however, much lower density of the final compounds was obtained.