Low-Temperature Crystal Nucleation of Enantiomeric Poly (lactic acids)*

We employed the commercial chip-calorimeter Flash DSC 1 to investigate the crystal nucleation behaviors of diblock copolymers and blends of half-half enantiomeric poly (lactic acids) at 35°C. The results show that crystal nucleation below the glass transition temperature can accelerates the crystallization rates at higher temperatures. For instance, the crystallization rate of 140°C increases by two orders of magnitude for the diblock copolymer. Such an accelerate can be attributed to the special interactions of stereo-complex crystals, because homo-crystal does not show such effect.