Crystallization of triethyl-citrate-plasticized poly(lactic acid) induced by chitin nanocrystals |
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Authors: | Shikha Singh Maria Lluisa Maspoch Kristiina Oksman |
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Affiliation: | 1. Division of Materials Science, Luleå University of Technology, SE-97 187 Luleå, Sweden;2. Centre Català del Plàstic (CCP), Universitat Politècnica de Catalunya Barcelona Tech (EEBE-UPC), C/Colom, 114 Terrassa, 08222 Spain |
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Abstract: | The aim of this study was to gain a better understanding of the crystallization behavior of triethyl-citrate-plasticized poly(lactic acid) (PLA–TEC) in the presence of chitin nanocrystals (ChNCs). The isothermal crystallization behavior of PLA–TEC was studied by polarized optical microscopy, scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction (XRD). Interestingly, the addition of just 1 wt % ChNCs in PLA–TEC increased the crystallization rate in the temperature range of 135–125 °C. The microscopy studies confirmed the presence of at least three distinct types of spherulites: negative, neutral, and ring banded. The ChNCs also increased the degree of crystallinity up to 32%, even at a fast cooling rate of 25 °C min−1. The XRD studies further revealed the nucleation effect induced by the addition of ChNCs and thus explained the faster crystallization rate. To conclude, the addition of a small amount (1 wt %) of ChNC to plasticized PLA significantly affected its nucleation, crystal size, and crystallization speed; therefore, the proposed route can be considered suitable for improving the crystallization behavior of PLA. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47936. |
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Keywords: | chitin nanocrystals isothermal crystallization microstructure plasticizer poly(lactic acid) |
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