An optimized melt spinning process to increase the productivity of nanofiber materials

The main disadvantage of the current electrospinning and related processes for producing nanofibers is low throughput rate, which is a challenge for quite some time. Traditional approach of studying the influence of one factor at time on nanofiber diameter does not give a complete picture of the process, where many interacting process parameters are being neglected. This paper reports a melt spinning process to increase the production rate of nanofiber materials. An additional attachment was fixed below the filament extruder of a melt spinning line. This attachment with controlled heated airflow arrangement stretches the filament coming out of the extruder by the process of sequential drawing which result in the formation of nanofiber materials. A die with segmented cross-section was used during melt extrusion process. A Box and Behnken factorial design of experiment was conducted to study the influence of multiple parameters on fiber/filament diameters. These parameters were distance of the first drawing zone from the die, airflow, and air temperature. The selected parameters were varied at three levels, -1, 0, and +1, respectively. The current setup produces fibers with diameter ranging from 820 to 1145nm, smallest diameter was 820nm. Among the selected parameters, the interaction effect of the air temperature and distance of the first drawing zone from the die was a dominant factor on the extrusion of nanofibers. These results show that in a multivariable process, interaction effect of the parameters played a major role in determining fiber diameter and it cannot be neglected.