Vliv keramických nanoprášků na reologii termoplastických suspenzí

Effect of ceramic nanopowders on rheology of thermoplastic suspensions

článek v časopise - ostatní, Jost

en

Rheological behaviour of thermoplastic polymer melts containing 20 to 50 vol.% of ceramic nanopowders was studied. For the preparation of thermoplastic polymer suspensions three ZrO2 powders with specific surface areas from 6.5 to 123 m2 g-1 were used. Using a capillary rheometer, viscous behaviour was examined in the temperature range from 100 to 150 degC and in the shear rate range from 100 to 1000 s-1. The viscosity of suspensions increased with increasing specific surface area of ceramic powder. The suspensions were of pseudoplastic nature, which was described by the power law. The power law exponent and the activation energy of viscous flow of suspensions decreased almost linearly with increasing specific surface area of the powder. The maximum volume fraction of the powder in the suspension also decreased with increasing specific surface area of the powder. The causes of the changes in viscous behaviour of the suspensions in dependence on the specific surface area of powders were discussed.

Bylo studováno reologické chování termoplastických polymerních suspenzí s obsahem 20 až 50 obj.% keramického prášku. Pro přípravu termoplastických polymerních suspenzí byly použity tři ZrO2 prášky s měrným povrchem od 6,5 do 123 m2 g-1. Viskózní chování bylo zjišťováno pomocí kapilárního reometru v rozsahu teplot 100-150 degC a smykových rychlostí 100-1000 s-1. Viskozita suspenzí rostla se zvyšujícím se měrným povrchem keramického prášku. Suspenze vykazovaly pseudoplastický charakter, který byl popsán mocninným zákonem. Exponent mocninného zákona i aktivační energie viskózního toku suspenzí klesaly téměř lineárně s rostoucím měrným povrchem prášku. Také maximální objemový zlomek prášku v suspenzi klesal s rostoucím měrným povrchem prášku. Byly diskutovány příčiny změn reologického chování suspenzí v závislosti na měrném povrchu prášků.

Rheological behaviour of thermoplastic polymer melts containing 20 to 50 vol.% of ceramic nanopowders was studied. For the preparation of thermoplastic polymer suspensions three ZrO2 powders with specific surface areas from 6.5 to 123 m2 g-1 were used. Using a capillary rheometer, viscous behaviour was examined in the temperature range from 100 to 150 degC and in the shear rate range from 100 to 1000 s-1. The viscosity of suspensions increased with increasing specific surface area of ceramic powder. The suspensions were of pseudoplastic nature, which was described by the power law. The power law exponent and the activation energy of viscous flow of suspensions decreased almost linearly with increasing specific surface area of the powder. The maximum volume fraction of the powder in the suspension also decreased with increasing specific surface area of the powder. The causes of the changes in viscous behaviour of the suspensions in dependence on the specific surface area of powders were discussed.

mixing, ZrO2, thermoplastic suspension, rheology

2005

01.01.2005

Elsevier Science

0272-8842

Ceramics International

31

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5