Cellulose Nanocrystals (CNC) are explored to stabilize oil/water emulsions for their ability to adsorb at the oil/water interface. In this work, the role of electrostatic forces in the CNC ability to stabilize oil/water emulsions is explored using canola oil/water and hexadecane/water as model systems. Canola oil/water and Hexadecane/ water (20/80, v/v) emulsions were stabilized with the addition of CNCs using ultrasonication. Emulsion droplet sizes range from 1 to 4 μm as measured by optical microscopy. It is found that CNC can stabilize oil/water emulsions regardless of their charge density. However, reducing the surface charge density, by adding salts and varying pH, can reduce the amount of CNC's required to form a stable emulsion. Just by adding 3 mM Na⁺ or 1 mM or less Ca⁺² to a CNC suspension, the amount of CNC reduced by 30% to stabilized 2 mL of Canola oil. On the other hand, adding salt increases the emulsion volume. The addition of 100 mM Na⁺ or the reduction of pH below 2 leads to the aggregation of CNC; emulsions formed under these conditions showed gel-like behavior. This work shows the potential of nanocellulose crystal in stabilizing food and industrial emulsions. This is of interest for applications where biodegradability, biocompatibility, and food grade requirements are needed.

The usage of renewable resources has become a hot topic upon the rising global awareness against fossil feedstock consumption. Lignin, the 2^nd most abundant natural polymer on Earth, is an aromatic biomacromolecule that holds a tremendous potential for the synthesis of biobased materials. The production of monomers and polymers from lignin has been investigated for years and keeps on expanding, as proven by the flourishing literature. However, the sustainability of the synthetic reactions has not been systematically analyzed. Herein, green chemistry plays a vital role in this area and provides several tools to design eco-friendly production methods. This critical review first describes the preeminent approaches for the synthesis of biobased monomers and polymers from lignin-derived compounds. In the second part, the “greenness” aspects of the 175 key monomer synthetic methods and 32 polymerization methods are evaluated based on selected criteria, including waste generation, atom efficiency, energy efficiency, usage of safer solvents, and biocatalytic methodology. The accessible green metrics, such as environmental factor (E factor) and atom economy are calculated to measure the greenness and to provide a quantitative base for strategic decisions. Furthermore, this study provides insights for the improvement opportunities and lights up the room for further developments. This review, aiming at scientists, industries and investors, strives to provide a critical outlook for the existing synthetic methods and motivates researchers to call for the integration of sustainability factors.