HPMC-silica suspensions

Moreover, the HPMC-silica suspensions show solid-like viscoelastic responses their dynamic storage moduli G are larger than the dynamic loss moduli G at small and linear strain ranges. On the other hand, the HPMC solution has much larger values of G than G in the frequency ranges from 0.1 to 100 rad/s due to liquid-like viscoelastic matter. 

Figure 3. Plots of v for various HPMC Silica suspensions as a Junction of (b /12 rjef Vp in the radial cell The dashed straight line has a slope of one.

Nakai et al. (175) studied the sterically stabilized silica suspension in aqueous hydroxypropyl(methyl)cellulose solution (HPMC). They confirmed, in part, the results of Otsubo (171) that both shear thinning... 

Figure 41. Shear moduli dependence on frequency for silica suspensions in 2.0% aqueous HPMC solutions (218).

An HPMC sample kindly supplied by Shin-Estu Chemical Co. was purified by the method described previously (5) and its molecular weight was determined to be 250x10 by the intrinsic viscosity measurement. PPG with the molecular weight of 725 was purchased from the Aldrich Chemical Co. and it was used without further purification. Silica suspensions were prepared by mechanically... 

HPMC chains adsorb onto the silica surface (9) and their adsorbed amounts are determined to be ca. 0.12g/g, irrespective of the silica concentration and HPMC. Figure 1 displays steady-state shear viscosities of the 5.0, 7.5, and 10.0 wt % silica suspensions dispersed in a 1.5g/100 mL HPMC solution, where the HPMC concentrations in the supernatants are 0.90, 0.60, and 0.30 g/100 mL in... 

Figure 1. Double-logarithmic plots of steady-state shear viscosities as a function of shear rate for 1,5 g/100 mL HPMC solution (open circle), 5.0 (filled triangle), 7.5 (filled circle), and 10.0 wt% (filled square) silica suspensions dispersed in a 1.5 g/100 mL HPMC solution.

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