Melt-electrospinning of thermoplastic polymers: An experimental and theoretical analysis

Over the past decade, there have been significant advancements in the area of electrospinning. A variety of polymers are being electrospun to form fibers on the nanoscale believed to have mechanical properties superior to those commercially available. Past research has focused on forming these fibers from a polymer solution but ever increasing demands for a cheaper, more environmentally friendly and safer alternative increases the demand to understand the feasibility of electrospinning from a polymer melt where very little research has been performed.; The effects of various melt-electrospinning parameters, including electric field strength, flow rate, and processing temperature on the morphology and fiber diameter of polypropylene of different tacticities and molecular weights and poly(ethylene terephthalate) were experimentally studied. It was shown that molecular weight was the predominant factor in determining the obtainable fiber diameter of the collected fibers. Observations prove that the tacticity also significantly influences the fiber diameter. Atactic polymers having molecular chains incapable of a high degree of orientation tend to produce larger diameter fibers than isotactic polymers capable of a high degree of orientation, despite the effect of molecular weights.; In addition, a model based on experimental and polymeric parameters and observations has been developed in an attempt to predict the diameter of the fibers that are being produced through the melt-electrospinning process. The model has been tested over all electric field strengths used in experimentation and has proven accurate for atactic polypropylene at small electric field strengths. By understanding the effects of each processing parameter on a specific response such as fiber diameter and being able to theoretically predict the fiber diameter being produced, the efficiency of the electrospinning process has been enhanced and it makes it a much more attractive alternative from many commercial applications were nonwoven materials are currently used.