The Effect of Mixed Filler Sizes on the Fiber Diameter and Pore Size of Electrospun Butyl Rubber Formulations

Electrospinning of thermosetting elastomers is a method for developing nonwoven membranes with a microporous structure, for use in dynamic applications (i.e. stretchable).  These membranes have potential for chemical protective clothing applications.  The most challenging concerns are the ability to control pore sizes, fiber diameter, permeability, and physical properties.  This work investigates the effect on fiber diameters and mechanical properties as a ratio of two different carbon black particulate sizes and percent loading.  Carbon black N110 and N990 are incorporated at various percents of total carbon black loading in a butyl rubber formulation. Resulting fibers are characterized for fiber diameter, pore size, and mechanical properties.  The effect of stretch on pore size is also examined using mercury intrusion.  The understanding of the effects of filler size and concentration on the electrospinning process will lead to the successful tailoring of nonwoven membranes with desired fiber diameter and pore size.