Citrate esters as plasticizers for poly(lactic acid)

Citrate esters were used as plasticizers with poly(lactic acid) (PLA). Films were extruded using a single-screw extruder with plasticizer contents of 10, 20, and 30% by weight. All of the citrate esters investigated were found to be effective in reducing the glass transition temperature and improving the elongation at break. It was observed that the plasticizing efficiency was higher for the intermediate-molecular-weight plasticizers. Hydrolytic and enzymatic degradation tests were conducted on these films. It was found that the lower-molecular-weight citrates increased the enzymatic degradation rate of PLA and the higher-molecular-weight citrates decreased the degradation rate as compared with that of unplasticized PLA. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1507–1513, 1997