Effect of extrusion, batch-mixing, and co-coagulation on the dispersion of CNCs in natural rubber - CNC nanocomposites

Abstract

In a bid to develop environmentally-friendly rubber materials, the use of renewable and sustainable additives that could provide suitable mechanical property enhancement is of great interest. In this study, cellulose nanocrystals (CNCs) are employed as reinforcing fillers due to their availability, sustainability, and excellent mechanical properties. Various processing methods of natural rubber (NR) – CNCs nanocomposite formulations were anticipated to provide varying levels of dispersibility and hence physical properties. The effects of batch mixing, co-coagulation, and extrusion processing methods have been investigated and compared on the dispersion of CNCs in NR. Various physical property testing methods were also employed to understand the effects of the processing on the NR-CNC vulcanizates. While co-coagulation and extrusion provided improved reinforcement of the nanocomposites attributed to the optimal dispersion of CNCs, batch mixing processed samples exhibited poor dispersion even at low CNCs loadings as observed from transmission electron microscopy and inferior composite properties.