Abstract: An improved apparatus and process for flash-spinning plexifilamentary film-fibrils are provided in which a static mixing device is provided in the conduit through which the polymer and spin agent are provided to the spin orifice of the flash spinning apparatus. Preferably, the flash-spinning apparatus includes a chamber immediately upstream of the spinning orifice and the static mixing device is disposed within the chamber. Plexifilamentary webs produced according to the invention have been found to have more densely spaced film-fibrils, more tie points and fewer holes. Bonded plexifilamentary sheets made from such webs have a more uniform thickness and a slightly higher tensile strength than sheets produced without the use of static mixers.