
L. Fliri: Carbonyls in Cellulose
Fri, 07 Feb
|Lecture hall L2
This thesis explores the modification of man-made cellulosic fibers through oxidative and thermal treatments to create renewable alternatives for synthetic materials, focusing on the introduction of carbonyl functionalities for improved material properties.


Time & Location
07 Feb 2025, 12:00 – 15:00 EET
Lecture hall L2, Vuorimiehentie 1, 02150 Espoo, Finland
About the Event
Content of the thesis:
This thesis aimed to advance the utilization of man-made cellulosic fibers (MMCFs) for non-standard applications. More specifically, it was attempted to generate renewable alternatives for two synthetic materials that currently dominate certain areas in the fiber market: 1) for polyurethane-based Elastane fibers which are used to enhance the stretchability of textiles. 2) for polyacrylonitrile (PAN) fibers, which represent the main precursor to produce carbon fibers (CFs) with acceptable mechanical properties.
For both endeavors the introduction of carbonyl functionalities into the cellulose structure was of major interest. To increase the flexibility of MMCFs the introduction of ring-opened dialdehyde cellulose (DAC) moieties into the rigid cellulose structure was examined. To enhance the yield of cellulose-based CFs the mechanism of the thermal dehydration reactions below 300 °C was investigated in detail.
The introduction of carbonyl functionalities seemingly only represents a minor change to the chemical structure of cellulose. However, it causes major changes to the solubility and stability of the materials, which also results in significant analytical challenges and has consequences for the materials properties. To obtain a better understanding of the operative processes they were investigated with state-of-the-art analytical techniques. Consequently, some pitfalls and side reactions in DAC chemistry could be highlighted and an updated mechanistic view on the initial thermal dehydration reactions of cellulose could be achieved.
Opponent: rofessor Stephen Eichhorn, University of Bristol, United Kingdom
Supervisor: Professor Michael Hummel, Aalto University School of Chemical Engineering
Link to electronic thesis: LINK
Link to the remote defence: LINK