Honeycomb Organization of Chitin Nanocrystals (ChNCs) in Nanocomposite Films of UV-Cured Waterborne Acrylated Epoxidized Soybean Oil Emulsified with ChNCs.

Stable biobased waterborne Pickering dispersions of acrylated epoxidized soybean oil (AESO) were developed using chitin nanocrystals (ChNCs) as sole emulsifier without any additives. Thin AESO-ChNC nanocomposite films were produced by UV-curing thin-coated layers of the AESO emulsion after water evaporation. The kinetics of photopolymerization were assessed by monitoring the consumption of the AESO acrylate groups by infrared spectroscopy (Fourier transform infrared (FTIR)). The curing was faster in the presence of ChNCs, with a disappearance of the induction period observed for neat AESO. The coating of AESO droplets with a thin layer of ChNCs was confirmed by scanning electron microscopy (SEM) observation. SEM and transmission electron microscopy (TEM) images revealed the honeycomb organization of ChNCs inside the cured AESO-ChNC films. The mechanical, thermal, and optical properties of the nanocomposite films were studied by dynamic mechanical analysis (DMA), tensile testing, differential scanning calorimetry (DSC), and transmittance measurement, as a function of ChNC content. The inclusion of ChNCs is strongly beneficial to increase the stiffness and strength of the cured films, without compromising its optical transparency. The ability of ChNCs to act as an emulsifier for AESO in replacement of synthetic surfactants and their strong reinforcing effect in UV-cured films offer new opportunities to produce waterborne stable dispersions from AESO for application in biobased coatings and adhesives.

Chitin nanocrystals as Pickering stabilizer for O/W emulsions: Effect of the oil chemical structure on the emulsion properties.

Chitin nanocrystals (ChNCs) produced by hydrochloric acid hydrolysis of chitin were used as stabilizing agent for oil-in-water (O/W) emulsification of soybean oil (SO), acrylated soybean oil (ASO), and epoxidized soybean oil (ESO). The emulsion stability, droplet size, and rheology of the emulsion were found to be significantly affected by the oil chemical structure. Strong interaction between ChNCs and the oil droplets enhanced the stabilizing efficiency of ChNCs through a Pickering effect, resulting in emulsions with low droplet size and long-term stability. The use of ChNCs as stabilizer for O/W emulsions in replacement of synthetic surfactants opens new avenues to produce emulsions for a wide variety of applications, including cosmetic products, coating, inks and adhesives.