Please consider attending the Preliminary Exam Seminar for Shikha Shrestha held Dec. 2, at 1:30 p.m., in ARMS 1021 "Effect of Rheological Behavior of Polymer Solution in Dry Spinning of Polymer Fibers" MATERIALS SCIENCE AND ENGINEERING SEMINAR "Effect of Rheological Behavior of Polymer Solution in Dry Spinning of Polymer Fibers" By Shikha Shrestha Purdue MSE Preliminary Exam Advisor: Professor Jeffrey P. Youngblood ABSTRACT Fiber spinning is one of the oldest polymer processing methods used for producing synthetic fibers. Depending on the specifications of polymer fibers, there are different types of spinning techniques - dry spinning, wet spinning and melt spinning. Dry spinning is one of the solution spinning methods in which the high vapor pressure polymer solution is introduced in the heating chamber, where it is converted to a solid fiber by controlled solvent evaporation in a spinline. There are many parameters that control fiber quality in dry spinning and includes rheological properties of polymer solution. They help to estimate the flow rate through the pipe and the capillaries of the spinneret and also when drawing fibers from the jet. The rheological properties of polymer solutions are affected by parameters like viscosity which increases with polymer concentration, molecular weight and decreases with temperature. Die swell is another variable influencing the rheological property and is bound to occur during the extrusion of filaments in dry spinning as a result of non-Newtonian shear flow of the spinning dope. Furthermore, for continuous and superior fibers, it is necessary to have a spinnable dope. The inferior fibers are formed due to the instability of the extrudate which is caused by capillary breakup and cohesive, brittle fracture. Hence, spinnability of polymer solution is required to form better fibers. Therefore, understanding the flow property of polymer-solvent mixture in dry spinning is necessary to obtain the ultimate continuous fibers with strong mechanical properties. Date: Wednesday, December 2, 2015 Time: 1:30 P.M. Place: ARMS 1021