Effect of Crystallization Temperature on the Interactive Crystallization Behavior of Poly(L-lactide)-block-Poly(ethylene glycol) Copolymer
writer：Jingjing Yang, Yongri Liang* and Charles C. Han*
keywords：Crystalline block copolymer, Interactive Crystallization Behavior
source：期刊
specific source：Polymer, 2015, 79(19), 56-64
Issue time：2015年
Crystallization behaviors of crystallineecrystalline diblock copolymers are important in understanding the structure evaluation. In this work, we investigated effects of crystallization temperature on the interactive crystallization behavior of crystallineecrystalline diblock copolymer of poly(L-lactide)-blockpoly(ethylene glycol) copolymer (PLLA-b-PEG) with differential scanning calorimetry (DSC), polarized optical microscopy (POM), atomic force microscopy (AFM), small and wide angle X-ray scattering (SAXS/WAXS) and Fourier transform infrared (FTIR) spectroscopy techniques. SAXS results showed that during the two-step crystallization process PEG blocks should crystallize within spaces from interlamellar or interfibrillar of PLLA crystals, and the microstructure formation in PLLA-b-PEG copolymer was greatly dependent on TC,PLLA (crystallization temperature of PLLA). Moreover, crystal nucleation and crystallization rate of PEG blocks were also dependent on Tc,PLLA. On the other hand, almost reversible crystalline structure changes of PLLA crystals was induced by crystallization and melting of PEG blocks. And the extent of crystalline structure change of PLLA blocks by PEG crystallization was increased with Tc,PLLA increasing.