| Abstract: | Poly(L ‐lactic acid) (PLLA)/gelatin blend membranes were prepared by solution casting method and using dimethyl sulfoxide (DMSO) as a cosolvent. Scanning electron microscopy measurement indicated that when the amounts of gelatin in PLLA/gelatin blend membranes are less than 5%, the sizes of phase separation of gelatin are in range of several hundred nanometers. These benefit in retaining the strength of PLLA membranes. X‐ray diffraction analysis revealed that the semicrystalline PLLA became amorphous and the melt temperature of crystalline PLLA changes from 56 to 38°C after it was processed in DMSO solvent. When the content of gelatin is less than 5%, the films not only retain a good mechanical property but also improve the hydrophilicity of PLLA. The molecular motion of PLLA in blend films were also investigated by solid state 13C CP/MAS NMR. On the basis of the result of relaxation times, it was found that the molecular motion of PLLA100 and PLLA/gelatin blends increased when compared with that of original PLLA. It was further verified that semicrystalline PLLA became amorphous. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 269–276, 2006 |
