The doctoral dissertation in the field of Sustainable Technologies will be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus and online.
What is the topic of your doctoral research? Why is it important to study the topic?
All-cellulose composites (ACCs) can be characterised as biocomposites, or single-polymer composites made entirely out of cellulose. Irrespective of the method used to produce ACCs, their reinforcement and matrix are formed using different sources of cellulose. Various solvent systems and technologies have been developed to create ACC materials in forms such as films, sheets, laminates and aerogels. This dissertation focuses on wood fibre textile-based ACC laminates produced using the aqueous NaOH-urea solvent system.
What are the key findings or observations of your doctoral research?
In this study, wood fibre textiles were transformed into ACCs using a one-step method in which fibres were partly dissolved, dried and resolidified to form a matrix around the non-soluble textile network. Lyocell-Spinnovafabrics containing a mixture of regenerated fibres and mechanically refined and spun wood fibres were employed as base of ACC fabrication.
In addition, differently constructed ACCs were formed and their properties were analysed using various methods, including mechanical tests (tensile, impact and flexural strength), thermal analyses (TGA, DSC and DMA), water absorbance, contact angle, micro-computed tomography (micro-CT) and scanning electron microscopy (SEM) imaging.
How can the results of your doctoral research be utilised in practice?
Based on these findings, this dissertation elucidates the potential of ACCs derived from cellulose-based woven and nonwoven textiles to challenge traditional bio composite materials in terms of mechanical strength, elongation and thermostability. The successful integration of textile materials with the NaOH-urea solvent system shows the potential of textile-based ACCs for diverse industrial applications where enhanced material strength and moisture management are essential.
Consequently, this study not only provides new insights into the identified knowledge gaps but also lays down a foundation for future research and development in sustainable composite materials, aligning with the industry’s need for high-performance, environmentally friendly alternatives.
The doctoral dissertation of Eija-Katriina Uusi-Tarkka, MSc, entitled Processing and properties of wood fibre textile all-cellulose composites be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus and online. The opponent will be Associate Professor Mikko Kanerva, University of Tampere, and the custos will be Professor Henrik Heräjärvi, University of Eastern Finland. Language of the public defence is English.
