roducing the yarn from nanofibres is considered as one of the great potentials in electrospinning. These yarns can be used in various fields of medical applications and filtration. Different polymers can be used in nanofiber yarn production. Many researches have been carried out on PAN nanofiber yarn production. These yarns had low mechanical properties without further heat setting. The aim of this research is to improve mechanical properties of PAN nanofiber yarns by blending with Nylon66 nanofibers.To produce Nylon66 nanofiber yarn with enhanced tenacity, three remarkable parameters are investigated. These parameters include solvent, molecular weight of polymer and polymer solution concentration. -cl 10% solution produce nanofiber yarn with 120.2 MPa tenacity. As a result, -cl 10% solution was selected to produce hybrid yarns with PAN nanofibers. The same diameter of fibers is an important factor in hybrid yarns. To fullfil this, PAN 10.5% solution with the same viscosity and nanofiber dimater with -cl 10% was selected. Hybrid yarns of PAN/ -cl were electrospun in different ratios. This hybrid yarn had nearly the same mechanical properties in comparison with PAN yarns. Auto-cl 12% was another solution with the same viscosity and nanofiber diameter with PAN 10.5%. This hybrid yarn was electrospun in different ratios too. PAN/Auto-cl 60:40 showed improved mechanical properties in comparision with PAN yarns. 14% is the other solution with the same nanofiber diameter with PAN 10.5% which was used to PAN/ hybrid yarn production. Tenacity and modulus of PAN/ 40:60 increased in compare with PAN yarns. Also, elastic recovery and moisture regain of PAN/Auto-cl hybrid yarn was investigated. Elastic recovery of PAN/Auto-cl 60:40 increased in compare with PAN yarns. In addition, hybrid yarn moisture regain increased by increasing the Nylon66 percentage.
