Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Poster: New Instruments and Methods

CPP 15.3: Poster

Dienstag, 27. März 2012, 18:15–20:15, Poster A

A novel Dilatometer to investigate the influence of pressure, cooling rate and shear rate on the specific Volume of polymers. — •Sibylle Jilg, Reinhard Forstner, and Wolfgang Stadlbauer — Transfercenter für Kunststofftechnik GmbH, Franz-Fritsch-Straße 11, 4600 Wels, Austria

These novel pvT-Dilatometer (Pirouette-pvT-Apparatus) was designed to measure the specific volume of polymers under processing conditions as found in injection moulding. So it is possible to investigate the specific volume as a function of temperature (up to 300°C), pressure (up to 1000 bar), cooling rate (up to 100°C/s) and shear rate (up to 180 1/s). The Pirouette is a combination of a traditional piston-die dilatometer and a Couette rheometer. This dilatometer can be used in several operating modes. Isobaric heating, isobaric cooling and isothermal experiments are possible. In this investigation measurements were performed with isotactic Homo-Polypropylenes in the isobaric cooling mode to show the dependency of the transition temperature from pressure, cooling rate and shear flow. It can be found that increasing pressure shifts the transition temperature to higher temperatures and higher cooling rates shifts the transition temperature to lower values. Higher shear temperatures shift the transition temperature to higher temperatures and higher pressures enhance the effect of shear. The specific volume after cooling to room temperature is mainly depending on cooling rate.