Novel regenerated cellulose films prepared by coagulating with water: Structure and properties

Regenerated films were successfully prepared from cellulose/NaOH/urea solution by coagulating with water at temperature from 25 to 45 degrees C. The results of solid (13)C NMR, wide angle X-ray diffraction, scanning electron microscopy (SEM) and tensile testing revealed that the cellulose films possessed homogeneous structure and cellulose II crystalline, similar to that prepared previously by coagulating with 5 wt% H(2)SO(4). By changing the coagulation temperature from 25 to 45 degrees C, tensile strength of the films was in the range of 85-139 MPa. Interestingly, the RC35 film coagulated at 35 degrees C exhibited the highest tensile strength (sigma(b) = 139 MPa). The inclusion complex associated with cellulose, NaOH and urea hydrates in the cellulose solution were broken by adding water (non-solvent), leading to the self-association of cellulose to regenerate through rearrangement of the hydrogen bonds. This work provided low-cost and green pathway to prepare cellulose films, which is important in industry. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.