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Post-extrusion heat-treatment as a facile method to enhance the mechanical properties of extruded xylan-based polymeric materials

AKKUS, Merve
Özkan, Necati
Bakir, Ufuk
Hemicelluloses are among the most abundant renewable polymers in nature, and their processing into biodegradable polymeric materials via extrusion was recently reported as a novel alternative technique for solvent casting. A simple heat-treatment step conducted after the extrusion of corn cob xylans was found to enhance the mechanical properties of strips by altering their moisture absorption behavior. Depending on the heat-treatment temperature, which varied between 60 degrees C and 150 degrees C, xylan- based strips with an ultimate tensile strength greater than 120 MPa, elongation at break of around 30% and elastic modulus of approximately 1.2 GPa were obtained. The equilibrium moisture content of the strips decreased with increasing heat-treatment temperature. Considering that water acts as a plasticizer for hemicellulose based materials, the changes in the mechanical properties were found to be associated with the changes in the equilibrium moisture contents of the strips.