Crystal polymorphism of polylactide and its composites by X-ray diffraction study

Autor: Atsushi Takahara, Shuhei Nozaki, Makoto Kido, Ya Ting Hsieh, Kazutaka Kamitani, Ken Kojio
Rok vydání: 2020
Předmět:
Zdroj: Polymer Journal. 52:755-763
ISSN: 1349-0540
0032-3896
DOI: 10.1038/s41428-020-0343-8
Popis: Polylactide (PLA) exhibits various types of crystal modifications depending on the preparation conditions, including the components. To solve the open question, a reliable calculation method for crystallinity, crystal forms, and composition in neat PLA and PLA composites was developed on the basis of temperature-dependent synchrotron wide-angle X-ray diffraction results. The relative composition of amorphous, α-form, and α’-form phases of PLA and its composites filled with halloysite nanotubes during heating was successfully obtained. It was found that only 47–56% of α’-form crystals transform into α-form crystals during a 2 °C/min heating process for PLA with a molecular weight of 54,300 g/mol. The loading of halloysite nanotubes decreases the cold crystallization and starting transition (α’ crystals transform into α-form crystals) temperatures of PLA. The crystallinity and the main diffraction peak intensity as a function of temperature were also analyzed. These results suggest that the α’-to-α form transition is a solid-solid phase transition. Polylactide (PLA) exhibits various types of crystal modifications depending on the preparation conditions, including the components. To solve the open question, a reliable calculation method for crystallinity, crystal forms and composition in neat PLA and PLA composites was developed on the basis of temperature-dependent synchrotron wide-angle X-ray diffraction results. The relative composition of amorphous, α-form, and α’-form phases of PLA and its composites filled with halloysite nanotubes during heating was successfully obtained.
Databáze: OpenAIRE
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