Filler Increases the Dynamic Viscosity

Filler Increases the Dynamic Viscosity Table 17.6 and 17.7 show examples of dynamic viscosity of rice hulls- and wood flour-lilled HDPE, respectively. 

One can see that the consistency index increases from 12,300 Pa.s for the neat HDPE (MFl 0.48) to 163,700 Pa.s for the 70% filled material (20-80 mesh ground rice hulls), and from 44,000 Pa.s for the neat HDPE (MFl 0.3) to 150,000,000 Pa.s for the 70% filled plastic (120-mesh wood flour). Overall, the viscosity increases by 

11-13 times on transition from neat HDPE to rice hulls-fllled HDPE and by 3400 times on that to wood flour-filled HDPE). The sharp increase of viscosity in the last case is a result, among other factors, of a sharp drop in the power-law index, from 

Wood flour from maple, 120 mesh, vacuum dried. The coupling agent was maleated polyethylene containing 1% (w/w) grafted maleic anhydride (Epolene G-2608, Eastman Chemicals). The lubricant was alkene bis fatty amid (Glycolube WP-2002, Lonza Inc.) [4]. 

TABLE 17.8 Effect of fillers in HDPE (MEI 0.50 g/10 min) on the apparent viscosity, consistency index (apparent viscosity at the shear rate of 1 s ) and povrer-law index, determined in the capiiiary rheometer (at 170°C) and the paraiiei piate rheometer (at 177°C) 

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