Investigation of the Effect of Filler Concentration on the Flow Characteristics of Filled Polyethylene Melts

Abstract

All polymer slurries that have a high concentration of filler are shear thinning. Shear thinning is an important characteristic of polymers, filled and unfilled, because it leads to being able to increase the throughput, shear rate in a die or mold without having to use substantially more power to increase the flow rate. With a perfect pseudoplastic fluid, n = 0, there would be no increase in energy as the flow rate is increased. This is of course not allowed by the second law of thermodynamics. Newtonian fluid based slurries show an increase in shear thinning as the concentration of "filler" increases above the percolation threshold. As the maximum packing factor is approached they approach a perfect pseudoplastic fluid. At times the shear thinning characteristics of a filled polymer does not increase substantially as the filler is increased in the same manner as the Newtonian fluid based slurry. Therefore, it is important to investigate the physics that controls shear thinning so that flow in extrusion and injection flow models can be more predictive when dealing with filled polymer systems.

Development of Hot‐Melt Extrusion Method to Produce Hydroxyapatite/Polycaprolactone Composite Filaments

“…An upper limit for melt viscosity of 10 000 Pa s has been suggested in the literature as a threshold for screw-type extruders, not to generate excessive torque and to avoid damaging the extruder. [36] This upper viscosity limit was confirmed for the produced filaments. The highlighted data points in Figure 4 show that all filaments were prepared under conditions that do not exceed 10 000 Pa s. Moreover, when the HME processing conditions were changed resulting in higher viscosities, the extruder torque drew near 2 Nm, engaging the fail-safe and stopping the machine.…”

“…This could be due to HAp hindering the melt flow by increasing the momentum dissipation inside the melt and preventing the polymer strands from easily slipping on each other, as was observed in similar systems. [ 33,34 ]…”

Effect of interaction from the reaction of carboxyl/epoxy hyperbranched polyesters on properties of feedstocks for metal injection molding

“…The result might due to the reaction between the carboxyl group and epoxy group in CTHP-m and ETHP-m, respectively. Therefore, CTHP-m and ETHP-m was more tightly packed through reaction so that some binder between powders released as shown in figure 7, and the close combination of powders reduced the contact area between the powder and the binder [36], thereby reducing the flow friction of powders in binder, and the flowability of feedstock increased. In our previous study [37], the interaction between powders improved the fluidity of the feedstock.…”

Modeling the thermodynamics and kinematics of spherical particle dispersion in polymer melts: Model derivation and simulation analysis

“…The dispersion and particle size distribution (PSD) are shown in Figure 2. [24,25] The transmission electron micrographs (TEMs) show that the final dispersion consists of primary particles that can be approximated as spheres,…”

“…% TiO 2 in LDPE concentrate masterbatch. [24,25] Particle size distributions were calculated with a commercial image analysis application.…”