| Autores |
Trujillo-Cayado, Luis A. , SANTOS GARCÍA, JENIFER, Carmen Alfaro, Ma , Calero, Nuria , Munoz, Jose |
| Abstract |
Finding alternatives to traditional organic solvents is one area in green chemistry that has generated great interest in recent years. This work provides new possibilities for the preparation of ecological oil-in-water (O/IN) emulsions. Model emulsions that may be used as matrices for agrochemical formulations have been investigated. Specifically, this paper deals with O/W emulsions formulated with a mixture of green solvents and a polyoxyethylene glycerol ester as emulsifier. First, an optimum ratio of solvents was found, after which the droplet size distribution, physical stability, and flow properties of emulsions obtained using two rotor-stator devices (toothed geometry vs emulsor screen) and two high-pressure homogenizers (high pressure valve homogenizer, HPVH, vs microfluidizer) were compared using several processing variables. Considering its low Turbiscan stability index and the absence of coalescence, 75/25 (N,N-dimethyldecanamide/a-pinene) was the optimum ratio of biosolvents. All samples showed droplet sizes with submicrometer diameters (both volumetric and Sauter means). However, both high-pressure homogenizers yielded smaller droplet sizes than rotor-stators. The combined use of multiple light scattering, rheology, and laser diffraction allowed the destabilization processes of emulsions to be monitored. The results obtained demonstrated that the emulsions prepared with a Y-shaped microfluidizer at 15000 psi (103.4 MPa) and 1-pass exhibited the highest physical stability. |
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