Multicomponent fibers are among the developed synthetic fibers for using various polymers’ properties for different applications. Developing a liquid core (bi-component) fiber is an open space in current fibers, specially bi-component fibers which can result a unique performance by mixing liquid’s dynamic properties with surrounding polymer’s mechanical characteristics for novel applications. In this study a special-designed spinneret was made, using previous Newtonian fluids co-flowing and CFD simulation along with core/shell extrusion trial results. Liquid core fiber, containing polypropylene sheath and complex ester core is developed, installing the desingned spin pack to melt spinning pilot plant along with CFD analysis in micro designed geometry and processing parameters were determined. Melt spinning trials by X5 drawing ratio and 1500 m/min winding speed resulted to a liquid core fiber (LCF) 50 mm in diameter with 15 mm diameter core. Melt-spun fiber was characterized for physical, mechanical and morphological properties and compared with two solid and hollow fibers as a reference. LCF’s linear density was more than hollow fiber and less than solid fiber. Liquid core fiber had lower tensile strength than reference fibers while its elongation was the maximum. After observation of core liquid in LCF under microscope, manipulation of the core liquid was investigated and liquid exchange was performed through a developed setup as a microfluidic characterstic, promissing for drug delivery applications. Microfluidic properties in LCF was compared by hollow fiber. Fluid dynamic analysis in micro scale was performed, developing a new method for attaching a branch of fibers to a syringe pump, and controlling liquid (water) pressure along with flow rate measurement. Hollow fiber showed lower flow resistance compare to the LCF which is due to the bigger internal diameter. Also theoretical alalysis confirmed the experimental fluid dynamic results, in accordance with Hagen-Poiseuille equation. Keywords: Bi-component fibers, Melt spinning, Rheology, Microfluidics, Fluid dynamics
