Improvement of mechanical and oxygen barrier properties of cellulose films by controlling drying conditions of regenerated cellulose hydrogels |
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Authors: | Quanling Yang Shuji Fujisawa Tsuguyuki Saito Akira Isogai |
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Institution: | (1) Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan; |
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Abstract: | Mechanical, thermal and oxygen barrier properties of regenerated cellulose films prepared from aqueous cellulose/alkali/urea
solutions can be markedly improved by controlling the drying conditions of the films. By pre-pressing followed by vacuum drying
under compression, the tensile strength, Young’s modulus, coefficient of thermal expansion and oxygen permeability of the
dried films reached 263 MPa, 7.3 GPa, 10.3 ppm K−1 and 0.0007 ml μm m−2 day−1 kPa−1, respectively. Thus, films produced in this way show the highest performance of regenerated cellulose films with no orientation
of cellulose chains reported to date. These improved properties are accompanied by a clear increase in cellulose II crystallinity
from 50 to 62% during pre-pressing/press-vacuum drying process. At the same time, the film density increased from 1.45 to
1.57 g cm−3, and the moisture content under equilibrium conditions decreased from 14.1 to 9.8%. Hence, the aqueous alkali/urea solvent
system has potential applications in producing new and environmentally friendly cellulose films with high performances through
control of the drying conditions. |
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Keywords: | |
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