Synthesis of Cross-Linked Vegetable Oil Nanoparticles

Vegetable oils are one of the most promising renewable feedstocks, and the synthesis of vegetable oil-based polymers via a simple and efficient green route was desirable. The inclusion of sulfur into biobased polymer materials can utilize abundant elemental sulfur derived from the byproducts of the oil industry. However, there are few studies aiming to obtain nanoparticles derived from vegetable oil and sulfur. Here, we proposed a facile method to conduct the vulcanization of soybean oil (SO) in a miniemulsion below 100 °C to prepare cross-linked but water-dispersible nanoparticles (poly(sulfur-cross-linked soybean oil) (PSSO)). PSSO nanoparticles with a gel content in the range of 0–80% and particle size in the range of 40–220 nm could be prepared. PSSO exhibited a low glass transition temperature (−38 °C) and could form a uniform and transparent film (Rq = 1.5 nm) at room temperature. The mechanical strength of the coating could be further increased (Derjaguin–Müller–Toporov (DMT) modulus of up to 2.8 GPa) after a simple heat treatment. Overall, this research provided a facile and green strategy for the effective utilization of vegetable oil and sulfur to produce water-dispersible polymer nanoparticles.