Abstract: An integrated process for the manufacture of lactide from a solution of lactic acid in de-ionized water comprising the sequential steps:A. Dehydrating the aqueous lactic acid in at least two stages to effect condensation polymerization of the lactic acid and the formation of oligomers in which the average number of monomer units is 8-25, the dehydration stages being conducted in equipment fabricated from low ferrous materials;B. Thermally cracking the oligomers in the presence of depolymerization catalyst to form lactide vapor of which the average residence time within the cracking zone is less than 15 seconds;C. Condensing the lactide vapor and fractionally distilling the condensate to remove concentrated lactide as a liquid sidestream; andD. Subjecting the concentrated lactide sidestream to melt crystallization to separate purified lactide having an Acidity Potential less than 6.

Abstract: A poly(lactic acid) composition having improved physical properties comprises a homogeneous solid solution of (a) a polymer having a number average molecular weight of 3,000-200,000 and selected from the group consisting of (1) poly(lactic acid), (2) copolymers of lactic acid containing at least 50 mole % lactic acid units, and (3) mixtures thereof; and (b) a plasticizer comprising an epoxidized oil selected from the group consisting of (1) epoxidized soybean oil; and (2) epoxidized linseed oil.