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Meral Akkoyun, Christian Carrot, Benoit Blottiere
On the use of an internal mixer to study the impregnation of carbon fillers by organic liquids

Appl. Rheol. 24:1 (2014) 13487 (8 pages)

Impregnation of organic liquid electrolytes in conductive powders is of major importance in the field of energy storage devices such as batteries or super-capacitors. Impregnation during mixing and processing operations becomes usual for practical reasons and requires a better understanding of the changes of the rheological behavior of the mix. In this paper, the impregnation of propylene carbonate (PC) and dimethyl sulfoxide (DMSO) in activated carbon (AC) and carbon black (CB) was studied by using an internal mixer. Monitoring of the torque of the filler/liquid blend as a function of the amount of liquid fed in the mixing chamber, enables to detect the transition from the solid friction of the dry powder to the lubricated liquid (or viscous) behaviour of the concentrated paste of wetted powder. The results were compared with data obtained by conventional nitrogen adsorption porosimetry combined with the knowledge of the molecular diameter of the liquids. A characteristic change was observed as soon as the liquid completely fills the porosity of the filler. Both tested liquids (DMSO and PC) impregnate more carbon black and the take-up rate is slightly higher for DMSO in comparison to PC because, as a polar liquid, DMSO has a better interaction with both fillers.

Cite this publication as follows:
Akkoyun M, Carrot C, Blottiere B: On the use of an internal mixer to study the impregnation of carbon fillers by organic liquids, Appl. Rheol. 24 (2014) 13487.

Christian Carrot
37th Meeting of the French Group of Rheology (GFR)

Appl. Rheol. 13:1 (2003) 29-30

Cite this publication as follows:
Carrot C: 37th Meeting of the French Group of Rheology (GFR), Appl. Rheol. 13 (2003) 29.

S. Brouillet-Fourmann, C. Carrot, N. Mignard,F. Prochazka
On the Use of an Internal Mixer For the Rheological Characterizattion of Maize Starch

Appl. Rheol. 12:4 (2002) 192-199

The rheological behaviour of hydrated maize starch is investigated by means of a Haake internal mixer equipped with a sealed chamber. Results were obtained at temperatures between 89 and 115°C with water content between 25 and 30%. Through a proper calibration torque measurements and rotation speeds are converted to shear stress and shear rate data and this leads to the plot of a flow curve in the 10 - 1000 s-1 range. The data are compared with results of capillary rheometer and show that the mixer enables a reproducible plastification of the maize starch. The viscosity of the maize starch in the high shear rate range can be described by an apparent power law taking into account the moisture and temperature effects. On a larger range of shear rate, a Carreau law is preferred but the dependence on the temperature can only be described with shift factors that require a moisture dependent activation energy. Finally, this later discrepancy can be avoided by using a reference temperature to fulfil the iso-free volume condition by taking a constant temperature difference towards the glass transition of the samples. The glass transition is calculated by the Couschman and Karasz equation.

Cite this publication as follows:
Brouillet-Fourmann S, Carrot C, Mignard N, Prochazka F: On the Use of an Internal Mixer For the Rheological Characterizattion of Maize Starch, Appl. Rheol. 12 (2002) 192.


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