solo
International Hazard
Posts: 3967
Registered: 9-12-2002
Location: Estados Unidos de La Republica Mexicana
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Mood: ....getting old and drowning in a sea of knowledge
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thixotropic ....properties of gel
Used in the test tubes doctors use to draw blood in which after a spin in the centrifuge the gel separated the serum from the red blood cells......gel
a thixotropic material....what uses can this be in chemistry......your opinion? It seems dentist exploit this properties in their use of filling
materials
PS Gel is a gel like material, composed of an acrylic polymer and inert fillers which provides thixotropic properties. PS Gel is a water insoluble and
chemically inert material with respect to constituents of blood- components.ยจ
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A study of the "thixotropic" property of elastomeric impression materials.
Chai J, Pang IC.
Int J Prosthodont. 1994 Mar-Apr;7(2):155-8.
Abstract
Shear-thinning, the decrease in the apparent viscosity of an impression material under a shear load, is a characteristic of many elastomeric
impression materials and improves handling properties. However, it is unknown whether the subsequent viscosity of such material continues to be lower.
This study compared the apparent viscosities of five elastomeric impression materials under two conditions. One group of the materials was manually
spatulated and injected through an impression syringe before being tested; the other group of materials was manually spatulated only. It was found
that the viscosities of these materials were not affected by the shear load applied during syringing.
Def. Thixotropy is the property of some non-newtonian pseudoplastic fluids to show a time-dependent
change in viscosity; the longer the fluid undergoes shear stress, the lower its viscosity.
http://en.wikipedia.org/wiki/Thixotropy
[Edited on 8-1-2008 by solo]
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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Mario.
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Registered: 13-1-2008
Location: Depends when.
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Mood: disoriented
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I know of no use in chemistry, but in painting and printing industry, the Tixo paste and tixotropic inks are used for quite a time. PLUS... some tixo
paints for hand painting make as good surface finish as if spray-painted - a can of such paint costs much, much more than any ordinary paint.
Obviously, you would want to use "tixo" in a place when you want certain particles preven from separating when not stirred for a time, but you want it
to be viscous liquid when stirred.
Sour cream is tixotropic too. I have no clue what use in chemistry that might find. 
Glad to find a place with fellow mad scientists... oops! Mad science is forbidden under the antiterrorist act. Let's talk about Pasteurization of milk
instead!
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