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Sodium Polyacrylate



Sodium polyacrylate dispersants like Allied Colloids 311 and Darvan #7 are used as an alternative to sodium silicate in casting bodies used in ceramics. Advantages are:

-a lower minimum viscosity can be achieved and maintained longer
-faster casting rate at minimum viscosity
-flatter over-deflocculation curve
-higher green strength allowing removal from mold at higher water content
-.05 to .2% required which is less than sodium silicate
-best absorption and penetration into plaster
-little or no efflorescence on molds (build up of fuzzy salt deposits) because the sodium ion is tied up in the organic deflocculant and will not exchange places with the calcium ion in the plaster as with soda ash and sodium silicate.
-less silica remains in the pore structure of the plaster.

This material is also used as a binder in ceramic bodies and to control specific gravity in glazes and engobes.

Related Information


Oxide Analysis Formula
Typecodes Additives for Ceramic Glazes
Materials that are added to glazes to impart physical working properties and usually burn away during firing. In industry all glazes, inks and engobes have additives, they are considered essential to control of cohesion, adhesion, suspension, dry hardness, surface leveling, rheology, speed-of-drying, etc. Among potters, it is common for glazes to have zero additives.
Typecodes Additives for Ceramic Bodies
Materials that are added to bodies to impart physical working properties and usually burn away during firing. Binders enable bodies with very low or zero clay content to have plasticity and dry hardness, they can give powders flow properties during pressing and impart rheological properties to clay slurries. Among potters however, it is common for bodies to have zero additives.
Articles Binders for Ceramic Bodies
An overview of the major types of organic and inorganic binders used in various different ceramic industries.
By Tony Hansen
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