화학공학소재연구정보센터
Polymer, Vol.51, No.12, 2748-2754, 2010
Effects of carbon nanotubes on rheological behavior in cellulose solution dissolved at low temperature
Multi-walled carbon nanotubes (MWNTs) were dispersed, for the first time, in cellulose solution in 9.5 wt% NaOH/4.5 wt% thiourea aqueous system pre-cooled to -5 degrees C. Dynamic light scattering and transmission electron microscopy results revealed a relatively strong interaction existed between MWNTs and the cellulose macromolecules, leading to a good dispersion of MWNTs in the cellulose solution. Their theological behaviors, especially the sol gel transition were investigated by using the advanced theological expanded system on the basis of Winter and Chambon theory. The gel point and gel concentration of the cellulose/MWNTs solution system were determined, indicating a regularly theological behavior. The data of loss tangent and relaxation exponent (n) indicated an enhancement in the viscoelasticity of the MWNTs/cellulose system. The results from scaling law before and beyond the sol gel transition in the MWNTs/cellulose system confirmed that the cluster formation and alteration of the gelation structure occurred at the gel point. Interestingly, the n values calculated by both the Winter and Chambon theory and scaling law were coincident only at relatively low temperature. The predicted gel strength values of the MWNTs/cellulose system were significantly larger than the pure cellulose solution, suggesting a relatively high strength, supported by the mechanical strength of the cellulose/MWNTs material. (c) 2010 Elsevier Ltd. All rights reserved.