The effect of sorbitan monooleate as surfactant in preparation of polyblend polylactic acid and polycaprolactone microspheres

Polyblend of polylactic acid (PLA) and polycaprolactone (PCL) microspheres with polymodal size distribution were synthesized through an emulsification-solvent evaporation method in water-in-oil (W/O) emulsions. Sorbitan monooleate was used as emulsion stabilizer and size controller in preparation of the microspheres. The effect of sorbitan monooleate addition in preparation on the size of the microspheres was studied by varying the volumes of sorbitan monooleate, the stirring speeds of emulsion formation, and dispersion times. The microspheres were characterized using Fourier Transform Infrared (FT-IR) and Particle Size Analyzer (PSA). The results show that there is no chemical interaction between PLA and PCL. This phenomenon can be seen from the FT-IR spectrum, which shows both PLA and PCL component. The particle size of microspheres decreased with the increasing volume of surfactant, emulsion stirring speed, and dispersion time. The size of microspheres obtained ranges from 0.4 μm to 10 m. Physical forms of microspheres were observed using optical microscope. The result shows that some microspheres are spherical and others are in aggregates form.