On PVT and Rheological Measurements of Polymer Melts

Abstract

Abstract The relation between PVT and rheological measurements of several polymer melts including polyethylenes, polypropylene, polystyrene, poly(methyl methacrylate), and polycarbonate has been taken into investigation. Pressure-temperature dependent viscosities, determined on rotational and backpressure-modified capillary rheometers, were fitted through the Carreau-Yasuda model. PVT data was analyzed by the help of the Simha-Somcynsky equation of state (SS EOS). The thermodynamical parameters of the SS EOS were connected to constant-stress viscosity (experimental) and zero-shear viscosity (extrapolated). The Doolittle relationship was modified into the form of <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:mrow> <m:mi>η</m:mi> <m:mtext> </m:mtext> <m:mo>=</m:mo> <m:mtext> </m:mtext> <m:mi>exp</m:mi> <m:mrow> <m:mo>(</m:mo> <m:mrow> <m:msub> <m:mi>C</m:mi> <m:mn>1</m:mn> </m:msub> <m:mtext> </m:mtext> <m:mi>ln</m:mi> <m:mrow> <m:mo>(</m:mo> <m:mrow> <m:mfrac> <m:msup> <m:mi>h</m:mi> <m:mo>′</m:mo> </m:msup> <m:mi>h</m:mi> </m:mfrac> </m:mrow> <m:mo>)</m:mo> </m:mrow> </m:mrow> <m:mo>)</m:mo> </m:mrow> </m:mrow> </m:math>. The relation was employed and tested for the data evaluation. It proved to be a good tool for linearization of PVT and rheological data.