Ring-opening polymerization of lactide production processes

Ring-opening polymerization of lactide production processes: first lactic acid dehydration Sodium lactate made lactide; Then lactide ring-opening polymerization of polylactic acid. Wherein the cyclization and purification of lactic acid is the preparation of lactide difficult and critical, this method can be obtained a high molecular weight lactic acid powder  but also to better meet a fiber-forming polymer and a bone fixation material requirements.
Direct polycondensation of lactic acid by direct polymerization of lactic acid refined, is the earliest and most simple way. The production process is simple, but the resulting polymer molecular weight is low and wide molecular weight distribution, the processing performance can not meet the needs of a fiber-forming polymer; but higher than the polymerization reaction under conditions of 180 ℃, resulting polymerization easily oxidized coloring matter, subject to certain restrictions apply.
As the raw material cause, poly poly-d-lactic acid (PDLA), poly-L-lactic acid (PLLA) and poly dL-lactic acid (PDLLA) of the points. Production of fiber commonly used PLLA.