Theoretical and empirical investigation into polymer blend morphology in fiber spinning

A promising way of developing new fiber forming materials is by utilization of polymer blends. The morphology of polymer blends has a significant effect on the properties of the resultant fiber. Morphological studies have shown that immiscible additives remain dispersed in the matrix as suspended droplets and that the droplets are elongated into fibrils under the action of shear or extensional forces during processing. The deformability of the dispersed phase is a controlling factor in deciding the resultant morphology and thereby the fiber properties. We report the results of a study of droplet deformation in uniaxial elongational flow under non isothermal conditions. A mathematical model is developed that simulates deformation conditions in fiber spinning. To test our model, a blend of polypropylene and polystyrene was spun into fibers. The blend morphology of the fibers is accurately predicted by the proposed model.