Crystallization Behavior of Stereo Diblock Poly(Lactide)s with Relatively Short Poly( D ‐Lactide) Segment from Partially Melted State

Stereo diblock poly(lactide)s (SDB‐PLAs) composed of relatively short poly(D‐lactide) (PDLA) and relatively long poly(L‐lactide) (PLLA) segments were synthesized, and the effects of incorporated short PDLA segments on crystallization behavior of SDB‐PLAs were investigated after melting at 200 °C, at which only homo‐crystallites were melted and stereocomplex (SC) crystallites remained un‐melted. During heating of melt‐quenched samples, SC crystallites and homo‐crystallites were contained and formed for D‐lactyl unit contents above 2.3% and below 28.8%, respectively, whereas after slow cooling from 200 °C, SC crystallites and homo‐crystallites were contained and formed for D‐lactyl unit contents above 0.9% and below 16.6%, respectively. By manipulating the overall molecular weight and the molecular weight of the PDLA segment, the SDB‐PLAs can attain accelerated crystallization and higher crystallinity compared to those of PLLAs.