Porous poly(L-lactic acid)/poly(ethylene glycol) blend films

Poly(L-lactic acid) (PLLA: M(w) = 19.4 X 10(4))/ poly(ethylene glycol) (PEG: M(w) = 400) blend films were formed by use of a solvent-cast technique. The properties and structures of these blend films were investigated. The Young's modulus of the PLLA decreased from 1220 to 417 MPa with the addition of PEG 5 wt %, but the elongation at break increased from 19 to 126%. The melting point of PLLA linearly decreased with increases in the PEG content (i.e., pure PLLA: 172.5degreesC, PLLA/PEG = 60/40 wt %: 159.6degreesC). The PEG 20 wt % blend film had a porous structure. The pore diameter was 3-5 mum. The alkali hydrolysis rate of this blend film was accelerated due to its porous structure. (C) 2004 Wiley Periodicals, Inc.