| 초록 |
The rheological properties of polyvinyl alcohol and polyacrylonitrile blend solutions dissolved in N-methyl-2-pyrrolidone were investigated in terms of blend composition and measuring temperature. Intrinsic viscosity suggested that solubility of the PVA/PAN blend solutions was reduced with increasing temperature. Over the range of 30 to 90 oC, the dynamic viscosity of the concentrated solutions was increased with increasing temperature. Further, the solution gave longer relaxation time, higher storage modulus and lower value of loss tangent at higher temperature. At low temperature, viscosity of blend solutions was only a little higher than pure PVA and PAN while storage modulus of pure PVA exhibited the highest value of all samples over the entire range of measurement. Temperature sweep measurement revealed the presence of critical temperature at which the viscosity of the concentrated solutions increased abruptly. Storage modulus and loss tangent of solutions showed same behavior. |
