Dielectric Spectroscopy: An Efficient Tool to Study the Interfacial Adhesion and Properties of Natural Rubber/Nanocellulose‐Based Green Nanocomposites

Abstract

The twenty-first century has witnessed remarkable achievements in green technology in materials science through the development of bionanocomposites. Nanofibrillated cellulose (NFCs) and cellulose nanocrystals (CNCs) extracted from date palm tree are proven as a good raw material for green nanocomposites. The objective of this study was to investigate the behavior change for natural rubber (NR) nanocomposite filled with NFC and CNC, focusing the attention on dielectric properties. Other properties such as swelling, mechanical, and dynamic mechanical are also presented to enable a better understanding of the microstructure properties relationship. For simplification, the results obtained for only one fraction of nanofiller are presented (2.5 wt%). It was found that residual lignin and hemicelluloses surrounding NFC limit water infiltration at filler–matrix interface, increase the tensile modulus, decrease the deformation at break, and increase the storage modulus E′. In addition, the damping factor tan δ is lower for NR-NFC than for NR-CNC nanocomposites. These results suggest that interactions between the NR matrix and the NFC were stronger. Moreover, CNCs that have lower diameter than NFCs generate more interfaces. Electrical characterization permitted a better understanding of the effect of nanocellulose structure. In fact, the number of free charges trapped at the interface is more important for CNC-based nanocomposites. Therefore, the Maxwell–Wagner–Sillars polarization is more intense. The interfacial adhesion was found to be higher for NR/NFC than for NR/CNC.