Viscosity filled grades

Polyphenylene sulfide is a high temperature, stiff, fire-resistant, chemically resistant plastic, which has a very low melt viscosity and accepts fillers and reinforcing agents very well. Talc, china clay, dolomite, quartz and glass fibre filled grades are all available but volumes are very small and the situation changes very rapidly. 

Figure 9.2. Reduced viscosity of polypropylene filled with different grades of calcium carbonate as a function of volume fraction. [Adapted, by permission from Gendron R, Daigneault L E, Tatibouet J, Dumoulin M M, Adv. Polym. Technol., 15, No.2, 1996, 111-25.]...

Results given in Table VII show that the viscosity versus shear rate variation of these three Santoprene grades fits the power law over the entire range from 10 to 5200 s . Both the viscosity and the extrudate swell at constant shear rate increase with decreasing rubber particle content (or increasing hardness). Thus, these olefinic thermoplastic vulcanizates essentially behave like highly filled fluids in flow. When compared with unvulcanised rubber (see previous sections) or polypropylene - EPDM blends (32), the extrudate swell appears low and there is no Newtonian viscosity plateau. 

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