Bio-based and Biodegradable Foams from Wheat Gluten using Up-Scalable Processes
Time: Fri 2024-10-11 10.00
Location: F3 (Flodis), Lindstedtsvägen 26 & 28, Stockholm
Video link: https://kth-se.zoom.us/j/68040338320
Language: English
Subject area: Fibre and Polymer Science
Doctoral student: Mercedes A. Bettelli , Polymera material
Opponent: Universitetslektor Anders Egede Daugaard, Technical University of Denmark, Danmark
Supervisor: Professor Mikael S. Hedenqvist, Polymera material, Wallenberg Wood Science Center; Professor Richard Olsson, Polymera material; Professor Eva Johansson,
QC 20240916
Embargo fram till 2025-10-11 godkänt av skolchef Amelie Eriksson Karlström via e-post
Abstract
In this thesis, the production of bio-based and biodegradable foams from wheat proteins (wheat gluten) is presented. Wheat gluten, a side stream from the ethanol/starch industry, was processed using both batch and continuous foaming methods. To produce the foams, glycerol, an effective protein plasticiser, was used, with two foaming agents common in food: sodium bicarbonate (SBC) and ammonium bicarbonate (ABC), to generate soft foams with both closed-and open-cell structures. ABC proved to be a better foaming agent in foam extrusion than SBC, but SBC performed well in the batch methods. Due to ABC’s low decomposition temperature, extrusion could take place at a temperature as low as 70 °C.
Three different multifunctional additives (citric acid, gallic acid and genipin) were also used to influence and improve the foam properties. The mechanical properties showed that some of the materials could be potentially useful in cushioning and sealing applications. The foams also showed a high absorption of saline (model substance for body fluid) and blood (in the form of sheep’s blood), even under mechanical pressure. Based on these results, a wheat gluten-based product was manufactured as a proof-of-concept.
The degradability of the foam in various relevant environments was studied. It was found that some foams degraded almost completely in soil after 8 weeks and in alkaline water after 5 weeks. It was also demonstrated that the foam also worked as a good fertilizer. As an alternative to direct composting when the foam is no longer used, the possibility of reusing the foam in a different form was evaluated. In this context, it was possible to produce plastic films from the foam.