Vegetable Oils Acting as Encapsulated Bioactives and Costabilizers in Miniemulsion Polymerization Reactions

Abstract

Vegetable oils with different chemical structures are successfully encapsulated and applied as costabilizers in miniemulsion polymerization reactions. The results are compared to hexadecane, a well-known costabilizer used for this type of polymerization. The great advantage of using vegetable oils is that besides acting as costabilizers, they are also encapsulated, increasing the application of the nanoparticles. Results show that kinetics tend to be slower with argan oil, due to the higher concentration of double bonds present in the oil. When coconut oil and jojoba oil are used, the kinetic rate kept nearly the same. The different types of costabilizers do not affect the average size of the particle, and are able to keep the miniemulsion stable throughout the reaction. DSC analysis shows a decrease in the glass transition temperature when the vegetable oils are used. However, after a long period of storage, the Tg of the polymers increases. STEM images show the formation of nanoparticles for hexadecane and the vegetable oils. However, the nanocapsule morphology appeares only when coconut oil, jojoba oil, and hexadecane are used, while for argan oil no phase separation can be detected in the polymer particle. Practical Applications: Miniemulsion polymerization reactions allow the production of polymeric nanoparticles in only one step with high encapsulation efficiency. To obtain a stable miniemulsion, it is necessary the addition of a costabilizer. The vegetable oils are chosen because besides acting as costabilizers the vegetable oils can increase the application of the nanoparticles since they have important characteristics and functionalities.

Synthesis of PMMA Nanoparticles Loaded with Geopropolis Extract from the Brazilian Stingless Bee Melipona quadrifasciata Lepeletier, 1836 by Miniemulsion Polymerization

“…[ 35 ] When incorporating coconut oil as a co‐stabilizer in the mini‐emulsion polymerization of MMA, Bigon et al also showed a reduction in the average weighted molecular weight ( M w ) from 20.05 × 10 5 g mol –1 to 18.56 × 10 5 g mol –1 and an increase in the polydispersity from 1.619 to 1.822, compared to the experiments in which hexadecane was used as a co‐stabilizer. [ 38 ] Bathfield et al also observed a reduction in the polymer molecular weight when incorporating triglycerides as co‐stabilizers in the vinyl acetate miniemulsion polymerization in comparison to the experiments in which only hexadecane was used as co‐stabilizer. [ 36 ]…”

“…Shorter polymer chains need less energy to promote their mobility, which reduces the glass transition temperature. [ 38 ] Other important fact that contributes to the reduction of T g is the plasticizer effect promoted by propolis compounds due to their lipophilic characteristic.…”

Vegetable Oil as a Continuous Phase in Inverse Emulsions: ARGET ATRP for Synthesis of Water-Soluble Polymers

“…Vegetable oils can effectively replace the organic solvents as the continuous phase in the inverse emulsion. − Plant-based oils exemplify a perfectly renewable resource, as they are not miscible with water; therefore, they can be exploited to prepare new polymer products in dispersed systems. , Vegetable oils comprise triacylglycerols composed of three fatty acids bound to a glycerol backbone, whose structure depends on the plant source. − Triglycerides bear several reactive sites, including double bonds and ester groups, opening up opportunities to customize new structures . In addition, vegetable oils were successfully applied as emulsion costabilizers . Interestingly, the industry frequently implements emulsion systems based on vegetable oils, specifically in designing cutting fluids , and diesel engine fuels …”

“…45 In addition, vegetable oils were successfully applied as emulsion costabilizers. 46 Interestingly, the industry frequently implements emulsion systems based on vegetable oils, specifically in designing cutting fluids 43,47 and diesel engine fuels. 48 In this contribution, several types of vegetable oils − rapeseed and sunflower oil, extra-virgin olive oil, and extravirgin avocado oil, were used for the first time as a continuous phase in the polymerization of 2-hydroxyethyl acrylate (HEA) via ARGET ATRP in an inverse emulsion.…”

ZnO and quercetin encapsulated nanoparticles for sun protection obtained by miniemulsion polymerization using alternative co-stabilizers

“…Miniemulsion polymerization is an in situ encapsulation technique, where polymer synthesis and encapsulation of the component of interest are performed in a single step [7]. Some authors have evaluated the use of alternative co-stabilizers, such as andiroba oil [8,9]; jojoba oil [8]; clove oil [10]; sunflower seed oil and linoleic acid [11]; linseed oil [9]; argan oil and coconut oil [12], being encapsulated as compounds of interest besides stabilizing the miniemulsion.…”