"This is the peer reviewed version of the following article: Hortós, M. , Anakabe, J. , Arrillaga, A. , Espino, S. and Bou, J. J. (2019), Effect of the annealing procedure and the molecular weight on the crystalline phase morphology and thermal properties of polylactide. Polym. Int., 68: 1767-1775, which has been published in final form at https://doi.org/10.1002/pi.5887. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived ...
"This is the peer reviewed version of the following article: Hortós, M. , Anakabe, J. , Arrillaga, A. , Espino, S. and Bou, J. J. (2019), Effect of the annealing procedure and the molecular weight on the crystalline phase morphology and thermal properties of polylactide. Polym. Int., 68: 1767-1775, which has been published in final form at https://doi.org/10.1002/pi.5887. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions."
The thermomechanical properties of poly(lactide) (PLA) are strongly related to its semicrystalline microstructure and morphology. Thermal annealing is a strategy to improve the crystallinity of PLA. However, the different techniques and specimen types needed for each kind of characterization could lead to misleading conclusions. In this work, annealed samples of three PLA grades with different molecular weights were studied by DSC, wide angle X-ray scattering and polarized optical microscopy (POM) and the results are related to their thermomechanical and impact properties. Special focus is put on the POM results obtained by different approaches and the suitability of each of them to be related to the thermomechanical properties. By annealing medium molecular weight PLA specimens at 140 °C an important increase of the heat distortion temperature was obtained, which was not related to the spherulite size but to the combination of high crystallinity degree together with high a/a' crystal type ratio. However, the impact properties of annealed PLA decreased with increase in the annealing temperature according to an increment in crystallinity and in the a/a' crystal ratio.
Citation
Hortós, M. [et al.]. Effect of the annealing procedure and the molecular weight on the crystalline phase morphology and thermal properties of polylactide. "Polymer international", 1 Gener 2019, vol. 68, núm. 10, p. 1767-1775.
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