University of Oulu

Patel, M. K., Hansson, F., Pitkänen, O., Geng, S., & Oksman, K. (2022). Biopolymer blends of poly(Lactic acid) and poly(Hydroxybutyrate) and their functionalization with glycerol triacetate and chitin nanocrystals for food packaging applications. ACS Applied Polymer Materials, 4(9), 6592–6601.

Biopolymer blends of poly(lactic acid) and poly(hydroxybutyrate) and their functionalization with glycerol triacetate and chitin nanocrystals for food packaging applications

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Author: Patel, Mitul Kumar1; Hansson, Freja1; Pitkänen, Olli2;
Organizations: 1Division of Materials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-97 187 Luleå, Sweden
2Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, 90570 Oulu, Finland
3Mechanical & Industrial Engineering (MIE), University of Toronto, Toronto, Ontario M5S 3G8, Canada
4Wallenberg Wood Science Center (WWSC); Luleå University of Technology, SE 97187 Luleå, Sweden
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 13.8 MB)
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Language: English
Published: American Chemical Society, 2022
Publish Date: 2022-10-17


Polylactic acid (PLA) is a biopolymer that has potential for use in food packaging applications; however, its low crystallinity and poor gas barrier properties limit its use. This study aimed to increase the understanding of the structure property relation of biopolymer blends and their nanocomposites. The crystallinity of the final materials and their effect on barrier properties was studied. Two strategies were performed: first, different concentrations of poly(hydroxybutyrate) (PHB; 10, 25, and 50 wt %) were compounded with PLA to facilitate the PHB spherulite development, and then, for further increase of the overall crystallinity, glycerol triacetate (GTA) functionalized chitin nanocrystals (ChNCs) were added. The PLA:PHB blend with 25 wt % PHB showed the formation of many very small PHB spherulites with the highest PHB crystallinity among the examined compositions and was selected as the matrix for the ChNC nanocomposites. Then, ChNCs with different concentrations (0.5, 1, and 2 wt %) were added to the 75:25 PLA:PHB blend using the liquid-assisted extrusion process in the presence of GTA. The addition of the ChNCs resulted in an improvement in the crystallization rate and degree of PHB crystallinity as well as mechanical properties. The nanocomposite with the highest crystallinity resulted in greatly decreased oxygen (O) and carbon dioxide (CO2) permeability and increased the overall mechanical properties compared to the blend with GTA. This study shows that the addition ChNCs in PLA:PHB can be a possible way to reach suitable gas barrier properties for food packaging films.

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Series: ACS applied polymer materials
ISSN: 2637-6105
ISSN-E: 2637-6105
ISSN-L: 2637-6105
Volume: 4
Issue: 9
Pages: 6592 - 6601
DOI: 10.1021/acsapm.2c00967
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: We are grateful for the funding provided by the Bio4Energy National Strategic Research Program and Horizon 2020 BBI project NewPack Grant No. 792261. Kempe Stiftelserna and Wallenberg Wood Science Center (WWSC) are acknowledged. We also express our gratitude to Laurens De Brauwer and Dr. Rakesh Nair (BBEPP, Belgium) for supplying the PHB and ChNCs used in the experiments, as well as to Niina Halonen, Topias Järvinen, and Krisztian Kordas (University of Oulu, Finland) for collaboration in barrier properties characterization.
EU Grant Number: (792261) NEWPACK - Development of new Competitive and Sustainable Bio-Based Plastics
Copyright information: © 2022 The Authors. Published by American Chemical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (