Rheology melt flow

Understanding the melt rheology of rubber nanocomposites is crucial from the processing perspective. Bandyopadhyay et al. [37] have studied the melt flow behavior of rubber-silica hybrid nanocomposites in a capillary rheometer. 

One of the common problems associated with underwater pelletizers is the tendency of the die holes to freeze off. This results in nonuniform polymer melt flow, increased pressure drop, and irregular extrudate shape. A detailed engineering analysis of pelletizers is performed which accounts for the complex interaction between the fluid mechanics and heat transfer processes in a single die hole. The pelletizer model is solved numerically to obtain velocity, temperature, and pressure profiles. Effect of operating conditions, and polymer rheology on die performance is evaluated and discussed. 

A comparison is made between a 3.5 melt flow conventional polypropylene homopolymer (Profax 6523) and a 7.0 melt flow, high-melt-strength, foamable PP homopolymer in extensional flow. The importance of extensional or elongational viscosity in the foam process is demonstrated and the way in which the rheological differences permit the production of low-density foam on tandem extrusion equipment is shown. 6 refs. 

Since polymer melt flow behaviour is strongly affected by the nature of the filler type, including its morphology, surface chemistry and concentration, rheological studies can also assist in the development of formulations designed to facilitate industrial processability. 

Ballman,R.L Rademacher,L.E., Farnham,W.H. Visualization of polystyrene melt flow. Presented at 1972 August U.S.-Japan joint seminar on polymer processing and rheology, Knoxville, Tenn. See J. Appl. Polymer Symp. 20 (1973). 

The melt flow under isothermal conditions, when it is described by the rheological equation for the Newtonian or power law liquid, has been studied in detail63 66). The flow of the non-Newtonian liquid in the channels of non-round cross section for the liquid obeying the Sutterby equation have also been studied 67). In particular, the flow in the channels of rectangular and trigonal cross section was studied. In the analysis of the non-isothermal flow, attention should be paid to the analysis 68) of pseudo-plastic Bingham media. 

Instron Capillary Rheometry. Melt flow rheology was measured according to procedures first proposed by Merz and Colwell (10) and supplied by the Instron Engineering Corp. 

Melt flow rheology measurements were obtained on the MBAS polymer using an Instron capillary rheometer. The data reported were obtained using an 0.056-inch capillary, 90° included angle, with an L/D of 36. In Figure 5 the maximum shear stress (lb/in2) is plotted vs. the apparent shear rate (sec 1). The apparent viscosity (lb-sec/in2) vs. tem-... 

H. Janeschitz-Kreigl, Polymer melt rheology and flow birefringence, Springer/Ver-lag (1983). 

H. Janeschitz-Kriegl, Polymer Melt Rheology and Flow Birefringence, Springer-Verlag, Berlin 1983. 

Fig. 12.17 Scanning electron micrograph of HDPE extruded at a shear rate slightly lower than the oscillation region, showing sharkskin. [Reprinted by permission from N. Bergem, Visualization Studies of Polymer Melt Flow Anomalies in Extruders, Proceedings of the Seventh International Congress on Rheology, Gothenberg, Sweden, 1976, p. 50.]...

N. Bergem, Visualization Studies of Polymer Melt Flow Anomalies in Extrusion, Proc 7th Int. Congr. on Rheology, Gothenburg, Sweden, 1976, p. 50. 

Janeschitz-Kriegl H, "Flow-birefringence of elasto-viscous polymer systems", Adv Polym Sci, 6 (1969) 170. Janeschitz-Kriegl H, "Polymer Melt Rheology and Flow Birefringence", Springer Verlag, New York, 1983. 

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