POLY(2-HYDROXYALKANOIC ACID) AND METHOD OF ITS MANUFACTURE

摘要

The invention relates to a method for manufacturing poly(2-hydroxyalkanoic acid). This method comprises the steps of a) mixing a cyclic diester of a 2-hydroxyalkanoic acid and a polymerization catalyst, b) polymerizing the cyclic diester to form poly(2-hydroxyalkanoic acid) in liquid phase, c) adding a phosphoric acid ester as a catalyst deactivating agent to the liquid phase, d) applying a devolatilisation step to the liquid phase, and e) allowing the poly(2-hydroxyalkanoic acid) to solidify. According to the invention, the catalyst deactivating agent is added after the devolatilisation step is applied. The invented method results in an improved melt stability of the manufactured polymer.