Recrystallization of L-PLA Fine Particles by Supercritical Anti-Solvent (SAS) Process

Abstract

Poly-L-lactic acid (L-PLA) particles were produced through a continuous supercritical anti-solvent (SAS) process in an effort to evaluate the possibility of controlling the microparticle size and distribution. SAS experiments were performed by studying the influences of the pressure, temperature, concentration of liquid solution, flow rate of anti-solvent and liquid solution, and nozzle diameter. SEM images of the processed materials were used to analyze the morphology, mean particle size, and particle size distribution (PSD). Upon optimization, L-PLA microparticles were successfully precipitated by the SAS process, using carbon dioxide (CO2) as the supercritical anti-solvent and methylene chloride (CH2Cl2) as the liquid solvent.