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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Focus Session: Interactions Between Water and Cellulose II
CPP 37.2: Talk
Thursday, March 20, 2025, 16:45–17:00, H34
Exploring Hygroexpansion of Cellulose Based Fibers via µCT — •Maximilian Fuchs1,2, Raimund Teubler2,3, Alexandra Serebrennikova1,2, and Karin Zojer1,2 — 1Institute for Solid State Physics, Graz University of Technology, Austria — 2Christian Doppler Laboratory for Mass Transport through Paper — 3Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Austria
Understanding the swelling of cellulose-lignin-based fibers is crucial for describing the processes involved in the uptake of water or other volatile organic compounds in paper. Microcomputed tomography (µCT) promises to monitor the hygroexpansion on a paper sheet level. However, extracting and analyzing individual fibers from the interwoven fiber network in these µCT images is challenging. We present a new approach to identify, extract, and analyze hollow fibers by focusing on the fiber lumen as the structural backbone. Using this approach, we quantify changes in fiber shape as the paper sheet absorbs water and another polar solvent, dimethyl sulfoxide (DMSO), from the vapor phase. We continue to observe these changes long after saturation, when no further mass is absorbed in the fibers. With both water and DMSO, the fiber wall thickness continues to increase even after reaching saturation. Furthermore, when exposed to water, the fibers tend to become rounder during swelling, suggesting fiber decollapse. In contrast, the data for DMSO indicates that the outermost fiber layer gets damaged, leading to unrestricted swelling once saturation is exceeded.
Keywords: fibers; microcomputed tomography; paper; swelling; water