Preparation and properties of multi-branched poly(D-lactide) derived from polyglycidol and its stereocomplex blends

Multi-branched poly(D-lactide)s (mbPDLAs) with various structures are synthesized via ring-opening polymer- ization by using polyglycidol (PG) macro-initiators. Their chemical structures and thermal properties are controlled by adjusting feed ratios of D-lactide (DLA) and PG. The materials are blended with commercial linear poly(L-lactide) (l-PLLA) to form a stereocomplex structure. Effects of mbPDLAs structures and l-PLLA/mbPDLA ratios on the blends' thermal, mechanical, and rheological properties are evaluated. Mechanical properties of the stereocomplex blends, espe- cially elongation at break and toughness, are dependent on the blend compositions, in which a 90:10 ratio exhibits the most desirable properties. The material also exhibits the lowest complex viscosity, which provides easy processing conditions. This is achieved by the incorporation of copolymers with multi-branched structures and an ability to form a much stronger stereocomplex structure.