Abstract
Storage and loss shear moduli of aqueous dispersions of microparticulated cellulose with different sizes (1.1μ m, 1.8μ m, 3.2μ m, 6.5μ m) increased with increasing temperature. Although the dispersions are not true gels, they showed a plateau in the frequency dependence of storage and loss moduli. The storage modulus of dispersions of microparticulated cellulose as a function of concentration increased by a power law with an exponent of three. Flow curves of dispersions showed hysteresis; shear stress observed during the increase in shear rate is larger than that observed during the decrease in shear rate. The hysteresis was more pronounced at higher temperatures. The storage modulus was separated into entropic and energetic contributions, and the entropic contribution was found to be positive for the temperature range from 5 to 70°C and to increase with increasing temperature. It is suggested that a tenuous network is formed in the dispersion, which becomes more solid-like at higher temperatures.
Published Version
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