Effect on Hot Melt Viscosity

Cellulose hber, obviously, increases viscosity of plastic hot melt. Furthermore, fiber from different species affects viscosity differently, even at the same particle size. For example, pine, juniper, and salt cedar (particle size 40-60 mesh), each at 50% amount w/w in HDPE, resulted in melt flow index (MFI) of 0.2,0.6, and 1.6, respectively. In other words, pine flour increased viscosity the most. Viscosity continued to increase with smaller wood flour particles (Table 3.12). 

TABLE 3.11 Effect of rice hulls and wood flour on the OIT of HDPE, fllled with Biodac of two different sizes (20-50 mesh and 100 mesh, Biodac 1 and Biodac 2, respectively) 

The composites were processed on the Brabender laboratory extruder. The OIT was measured at 190°C. The OIT values show the resistance of the material to oxidation The higher the OIT, the higher the resistance. The amount of Biodac was 28% in all cases. The amount of rice hulls and sawdust was 32% in all the cases. The amount of HDPE was 40% in all the cases. 

TABLE 3.12 MFI of HDPE filled with 50% (w/w) of various wood flour types [130] 

Wood Melt flow index for particle size, mesh  

---