Effects of various liquid organic solvents on solvent-induced crystallization of amorphous poly(lactic acid) film

The effects of 60 organic solvent on poly(lactic acid) (PLA) were systematically investigated using the Hansen solubility parameter (HSP). The hydrogen bonding solubility parameter accurately reflects the solubility of PLA films using HSP but it depends on hydrogen bonding, as well as dispersion and polar parameters. The PLA films immersed in organic solvent became cloudy and showed no changes in chemical structure. However, solvent-induced crystallization of the PLA films was observed. Crystalline structures do not dependent on the organic solvent but on the degree of swelling. The organic solvent-induced crystallization formed a crystallized mixture of a- and -forms. The density of the crystalline PLA films was lower than that of amorphous PLA films. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013