Reinforcement of rubber nanocomposite thin sheets by percolation of pristine cellulose nanocrystals

Research on the use of bio-based material rather than fossil fuel-based synthetic polymers is of considerable value due to the increasing interest in biodegradable and ecofriendly products. This paper describes an in-depth analysis of the effect of cellulose nanocrystals (CNC), a promising nanomaterial filler derived from cellulosic biomass, on the mechanical properties of rubber latex thin sheets. Sheets of styrene butadiene rubber (SBR) and its bio-based alternative, natural rubber (NR) were tested and compared. Percolation of CNC was studied within the rubber matrices, where the tear strength, water permeability, and water absorption increased due to the formation of a continuous network of CNC within the polymer thin sheets. The rubber nanocomposites were resistant to tear propagation, caused by increased tortuosity along the tear path brought about by CNC dispersion and filler network formation. The CNC reinforcement yielded thin sheets that were much stronger and more durable than their non-reinforced counterparts. Additionally, the increased water uptake of the sheets could aid in the biodegradation of the polymer. Thus, CNC is found to be an excellent functional filler in rubber sheets, where its formation of a percolating network significantly improved their properties.