Effects of annealing temperature (Ta: 80-140°C) and time (ta: 3-30 h) on the crystalline phase tr... more Effects of annealing temperature (Ta: 80-140°C) and time (ta: 3-30 h) on the crystalline phase transition in poly(lactic acid) (PLA) were studied by Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). In the DSC curves, the sample annealed at Ta=80°C with time interval (ta: 10-30 h) demonstrates a peculiarly small exothermal peak (Texo) around 130°C, just prior to the melting point, corresponding to the disorder-to-order (a’-to- a) phase transition, while the sample annealed at temperature (Ta: 90-110°C) shows a double melting behavior considered as the a'- a phase transition. At Ta>110°C, the a′ -form of PLA was found to transform into the a one during the annealing process. The a’- a phase transition around 100°C (Ta: 90-110°C), determined from the two melting peaks (Tm1 and Tm2) as function of Ta at different times ta, shows a good correlation with the substantial increase in the crystallinity rate (Xc) with a maximum of 32% at Ta=120°C. Towards ...
Effects of annealing temperature (Ta: 80-140°C) and time (ta: 3-30 h) on the crystalline phase tr... more Effects of annealing temperature (Ta: 80-140°C) and time (ta: 3-30 h) on the crystalline phase transition in poly(lactic acid) (PLA) were studied by Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). In the DSC curves, the sample annealed at Ta=80°C with time interval (ta: 10-30 h) demonstrates a peculiarly small exothermal peak (Texo) around 130°C, just prior to the melting point, corresponding to the disorder-to-order (a’-to- a) phase transition, while the sample annealed at temperature (Ta: 90-110°C) shows a double melting behavior considered as the a'- a phase transition. At Ta>110°C, the a′ -form of PLA was found to transform into the a one during the annealing process. The a’- a phase transition around 100°C (Ta: 90-110°C), determined from the two melting peaks (Tm1 and Tm2) as function of Ta at different times ta, shows a good correlation with the substantial increase in the crystallinity rate (Xc) with a maximum of 32% at Ta=120°C. Towards ...
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Papers by Lina BENKRALED