Poly(l-lactic acid) short fibers prepared by solvent evaporation using sodium tripolyphosphate

A porous material consisting of biodegradable polymer fibers may be one of the best candidates for implants used in the regeneration of damaged tissue, because it has a continuous pore structure that would allow ingrowth of nutriments, tissues, blood vessels or cells. In the present work, short fibers of biodegradable poly(l-lactic acid) (PLLA) were successfully prepared by the dropwise addition of PLLA dissolved in methylene chloride to a poly(vinyl alcohol) (PVA) solution containing sodium tripolyphosphate with stirring. It was suggested that droplets of the PLLA solution form spheres coated with PVA, which are then deformed into fibrous shapes due to stirring. The length of fibers was 200-800 μm and was controlled by the stirring rate, the PLLA concentration of the droplets and the PVA concentration. A PLLA porous block could be easily prepared by sintering the PLLA fibers at 173 °C for 10 min. The material had a continuous pore structure with the average pore size of approximately 40 μm and porosity of about 80%.