Cast extrusion of low gas permeability bioplastic sheets in PLA/PBS and PLA/PHB binary blends

ABSTRACT

Binary blends based on polylactic acid (PLA) and other biodegradable polyesters from renewable sources (namely, polybutylene succinate (PBS) and poly-3-hydroxybutyrate (PHB)) were prepared by reactive compounding extrusion. The achieved polymeric compounds were reprocessed by cast extrusion to manufacture the corresponding bioplastic sheets. Three different binary blends, one of which also including tocopherol, an oxygen scavenger, were investigated to ensure high-barrier of the bioplastic sheets to oxygen permeation. Physical, mechanical and chemical properties of the bioplastic sheets were, therefore, comparatively evaluated by differential scanning calorimetry, infrared spectroscopy, tensile tests and gas permeability. The experimental results showed a remarkable improvement in the oxygen barrier properties, especially on sheets manufactured in the PLA/PHB binary blend, without negatively affecting their thermo-mechanical response. Based on experimental evidences, the PLA/PHB binary blend is found to be extremely promising for the development of bio-based and biodegradable polymeric materials with low oxygen permeation, that is, for the development of suitable alternatives to conventional and highly pollutant oil-based plastics.

KEYWORDS:

• Reactive extrusion
• Cast extrusion
• polylactic acid
• bio-based polyesters
• oxygen barrier

Acknowledgments

Mrs. Federica Lovino is kindly acknowledged for her support during the development of the experimental tests.

Additional information

Notes on contributors

C. Aversa

C. Aversa is PhD Student at the University of Rome Tor Vergata. She received her master's degree in Mechanical Engineering from the University of Rome Sapienza in 2016. Since 2016 her research activity is focused on the development of biomaterials. She has co-authored several articles in the field of compostable polymers.

M. Barletta

M. Barletta is associate Professor, at the Department of Mechanical Engineering, University of Roma Tre. The research activities of Prof. Barletta are in the field of Manufacturing and Materials Engineering, focusing on design, development and implementation of innovative engineered materials and on related manufacturing technologies. Prof. Barletta has published over 200 papers on peer reviewed indexed and high impact factor international journals. In addition, Prof. Barletta has held 60 lectures, some as invited speaker, to international conferences, events or fairies. Prof. Barletta has also deposited 7 national and international patents.

M. Puopolo

M. Puopolo is Assistant Professor at the University of Roma Tre. She obtained her doctoral degree in Mechanical Engineering from the University of Rome “Sapienza” in 2016. She cooperates in the teaching activities of the classes in Manufacturing Engineering and Laboratory of Manufacturing Engineering for bachelor’s degree students in Mechanical Engineering. She has published over 29 papers in international journals. Her publication topics include compostable materials and polymeric blends.

S. Vesco

S. Vesco is Assistant Professor in Manufacturing Engineering at Department of Enterprise Engineering, University of Rome ‘Tor Vergata’. He currently teaches Laboratory of Manufacturing Engineering in Management Engineering. He spent most of research efforts in the development of advanced coating processes, especially in manufacturing and characterization of organic and inorganic coatings. She is currently collaborating in several research activities on engineered bio materials. In the last 10 years she published 41 papers on national and international journals.