ABSTRACT
Novel polylactic acid-based composites were prepared for the first time by melt-blending urethanization using bark polyflavonoids, and polymeric methyl diisocyanate. Rheological, morphological, structural, thermal, and mechanical properties were studied. Polymerization between polyflavonoids and isocyanate during the melt-blending was demonstrated by spectroscopy, confocal microscopy, and thermal analysis. Polyflavonoids improved the blend processability and affected the polylactic acid-crystallization, blend-urethanization, and flexural features. Polyphenols act as nucleating agent, and the effect was highly influenced by the polymeric methyl diisocyanate-charge, and the polyflavonoids-content. Low polymeric methyl diisocyanate-loading (10 wt%) degrades the elasticity modulus (E), while the highest polymeric (20 wt%) improved the miscibility between the polylactic acid polymer-matrix and the polyflavonoids.
GRAPHICAL ABSTRACT
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Aknowledgments
The authors thank the Basal Project PFB-27 from Technological Development Unit (UDT), Concepción University, Chile. In addition, authors also like to thanks to MSc. Joanna Tereszczuk, and Germán Osorio (Advance Microscopy Center, CMA), from Concepción University, Chile, for the technical assistance regarding confocal microscopy, and image-processing, respectively. The support of Mr. Richard Anthony Riquelme Beque in a framework of the FONDECYT Project is recognized with gratitude.