| 초록 |
Poly olefin(POK) fiber is one of the high-performance engineering materials. POK fibers are prepared by spinning of aqueous POK solutions in complex metal salts. It is recognized that the spinning dope of POK is physically unstable. Consequently it is prerequisite to understand the effects of thermal history on the rheological properties of the spinning dope to design the spinning process. The effects of concentration, shear rate, and temperature on the physical state of the solution systems were examined by rheological responses. Bingham behavior was observed at 30 and 90 oC. The heterogeneity of the solution at 30 oC disappeared when reheated to 50oC. On the otherhand, the zero yield stress at 50oC verified that there was no heterogeneity in the solution. With increasing temperature from 50 to 90oC, however, the viscosity of the solution was increased and Bingham behavior got more noticeable. The solution produced an irreversible heterogeneity at temperature higher than 70oC. |
