Mid Sweden University

The demands for alternatives to fossil-based materials for the packaging and building sector is rapidly increasing as new regulations and laws are set. The usage of such materials in low- density applications is increasingly questioned since only a small amount is recycled and a large part ends up in the environment where it has a very long decomposition time and contributes to the emergence of microplastics in our marine eco systems. Alternatives to fossil- based low-density materials has been demonstrated using e.g., starch [1] and cellulose [2] as raw materials. However, challenges remain regarding the process parameters and properties such as strength and water integrity. To fulfil these properties requested by the specification owners, understanding is needed regarding which tools that are available for incorporating wet-integrity and hydrophobicity without causing the wet foam to collapse during the foaming or drying process. It is also of highest importance to have an early understanding of how such materials can be recycled and/or bio-degraded to fit a circular economy. In this study two different cross-linkers and two different types of hydrophobisers are used to obtain a wet stable and a water repelling low-density material. The wet foams are characterized by measuring the foamability and foam stability and the dry foams are characterized in terms of structure, porosity and degradability. Two demonstrators have been produced based on the most promising material composition and the up-scaling processes of the developed foaming technology to both batch-wise and continuous fabrication of composite foams is underway. Finally, a biodegradation study was conducted and evaluated.

[1] S. Chaireh, P. Ngasatool, and K. Kaewtatip, “Novel composite foam made from starch and water hyacinth with beeswax coating for food packaging applications,” Int. J. Biol. Macromol., vol. 165, pp. 1382–1391, 2020

[2] C. Qin, M. Yao, Y. Liu, Y. Yang, Y. Zong, and H. Zhao, “MFC/NFC-based foam/aerogel for production of porous materials: Preparation, properties and applications,” Materials (Basel)., vol. 13, no. 23, pp. 1–21, 2020