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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: Polymer dynamics

CPP 21.12: Vortrag

Dienstag, 17. März 2015, 12:30–12:45, C 264

Water enhanced dynamics of cellulose paper — •Björn Kuttich, Ann-Kathrin Grefe, and Bernd Stühn — Experimental Condensed Matter Physics, TU Darmstadt, Germany

With over 50 weight percent cellulose represents the main part of plant cells. In terms of soft matter physics it is a rather complex and important biopolymer. Corresponding to its biological application cellulose is insoluble in water, but due to the monomers hydroxy groups it has a hygroscopic tendency. In industrial applications cellulose is the major component of paper, where water uptake can become important during manufacturing or processing.

While hydration effects on crystalline cellulose are already investigated the dynamics in cellulose papers, where highly oriented cellulose fibres are used, are less understood. In this work we therefore focus on a systematic variation of the hydration level of cellulose paper with different porosities. By using a hydration chamber for the humidification process, in which the relative air humidity can precisely be tuned, a water content in the sample between a few weight percent of water up to almost 20 percent can be realised. While our investigations by dielectric spectroscopy show only minor influences of the papers porosity, accelerated dynamics due to the presence of water become apparent. In contrast to the acceleration also the suppression of a local relaxation mode, which is not observed for crystalline cellulose, is found. To monitor water uptake of the sample and its characteristic time scale, all measurements are accompanied by time resolved weighing experiments, which reveal an uniform hydration process.