Die swell of 0.5 wt% MW 4×106 g/mol PEO solution laden without and with 2.34 wt% 10-20nm silica nanoparticles

#### Daniel D. Joseph, University of Minnesota, August 2005

Below are experimental pictures and movies for die swell of Die swell of 0.5 wt% MW 4×106 g/mol PEO solution laden with and with 2.34 wt% 10-20nm silica nanoparticles. Seeding the PEO solutions with the silica nanoparticles greatly increases the swell ratio to a value slightly less than three at the maximum extrusion velocity Uf = 217.7 cm/s.

(a)

Uf = 31.86 cm/s            Uf = 67.90 cm/s            Uf = 137.2 cm/s            Uf = 217.7 cm/s

(b)

Uf = 31.86 cm/s            Uf = 67.90 cm/s            Uf = 137.2 cm/s            Uf = 217.7 cm/s

Figure 00000. Die swell of a 0.5 wt% aqueous 4M solution with and without nanoparticles; the initial volume and the suction speed are the same in the two cases. (a) Without particles. There is no die swell for low fluid speeds and very weak die swell for high speeds. (b) The 4M/2.34% solution. The die swell is much strong and it becomes stronger with the increase of fluid speed.