Biosourced Polymeric Emulsifiers for Miniemulsion Copolymerization of Myrcene and Styrene: Toward Biobased Waterborne Latex as Pickering Emulsion Stabilizer.

Biobased waterborne latexes were synthesized by miniemulsion radical copolymerization of a biosourced ß-myrcene (My) terpenic monomer and styrene (S). Biobased amphiphilic copolymers were designed to act as stabilizers of the initial monomer droplets and the polymer colloids dispersed in the water phase. Two types of hydrophilic polymer backbones were hydrophobically modified by terpene molecules to synthesize two series of amphiphilic copolymers with various degrees of substitution. The first series consists of poly(acrylic acid) modified with tetrahydrogeraniol moieties (PAA-g-THG) and the second series is based on the polysaccharide carboxymethylpullulan amino-functionalized with dihydromyrcenol moieties (CMP-g-(NH-DHM)). The produced waterborne latexes with diameters between 160 and 300 nm and were composed of polymers with varying glass transition temperatures (Tg, PMy = -60 °C, Tg, P(My-co-S) = -14 °C, Tg, PS = 105 °C) depending on the molar fraction of biobased ß-myrcene (fMy,0 = 0, 0.43, or 1). The latexes successfully stabilized dodecane-in-water and water-in-dodecane emulsions for months at all compositions. The waterborne latexes composed of low Tg poly(ß-myrcene) caused interesting different behavior during drying of the emulsions compared to polystyrene latexes.

Highly Concentrated Emulsions Containing High Loads of Pterostilbene.

Pterostilbene is a highly researched molecule due to its bioactivity. However, its hydrophobicity limits its application. For this reason, researchers have sought to encapsulate pterostilbene (namely, in oil-in-water emulsion) to increase its availability. Studies are lacking when it comes to the effects of pterostilbene and its concentration at the oil/water interface. This paper discusses the effects of oil types, storage temperature, and pterostilbene concentration on the stability of the emulsions, as well as the interactions between encapsulated pterostilbene and the oil and water phases. Results showed that pterostilbene is present at the oil/water interface, affecting the interfacial tension and consequently the droplet size. It was also shown that encapsulation efficiency is affected by the storage temperature and oil type. Finally, it was proven that, according to oil types and storage temperature, the stability of pterostilbene to light is affected.