Preparation of Polyvinyl Alcohol (PVA) Solutions
Polyvinyl Alcohol (PVA, sometimes referred to as PVOH) is a water soluble polymer used widely in adhesives, paints, sealants, coatings, textiles, plastics, etc. The polymer is normally supplied in powder form and several grades are available with varying viscosity and solubility characteristics.
In the Silverson how to video, find out how a Silverson high shear mixer is able to disperse and solubilise PVA powder in hot water, reducing mixing times to a fraction of that taken by conventional methods.
PVA is soluble in hot and cold water. This should not be confused with Polyvinyl Acetate, also known as PVA (sometimes PVAc) which is insoluble in water. The Polyvinyl Alcohol powder is slowly added to cold water to avoid formation of lumps, as it becomes sticky and the tendency to form lumps increases as temperature rises. In some cases water at lower than ambient temperature may be used to reduce this risk. Once the powder is fully dispersed the mix is heated to the temperature at which the polymer becomes solubilised (ranging from 90ºC to 98ºC - this depends on the grade of PVA used). Mixing continues at this temperature until the PVA is fully solubilised. Depending on the grade of material and efficiency of the agitation system this can take some time to achieve.
Processing in this way, and with conventional agitators can give rise to a number of problems. These include difficulty incorporating the powder, agglomerates remaining in the mix and aeration problems.
With a Silverson high shear mixer, these problems can be avoided.
How to Mix PVA Solutions with Silverson High Shear Mixers
Silverson Machines’ high shear mixing technology allows the PVA powder to be effectively dispersed into hot water, Here’s how:
The vessel is charged with hot water and the mixer is started. The PVA is added to the water and is rapidly wetted out and incorporated into the liquid. The hi...
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Silverson Machines’ high shear mixing technology allows the PVA powder to be effectively dispersed into hot water, Here’s how:
The vessel is charged with hot water and the mixer is started. The PVA is added to the water and is rapidly wetted out and incorporated into the liquid. The high speed rotation of the rotor creates a powerful suction which draws ingredients into the mixer's workhead.
Centrifugal force drives the materials to the periphery of the workhead where they are subjected to intense high shear in the gap between the rotor and stator before being forced out through the holes in the stator and projected back into the mix. Any agglomerates are rapidly dispersed.
To find out more, visit the Silverson website, or contact us today to discuss your mixing requirements.
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Published by Silverson Machines on Nov 01, 2023
Silverson Machines
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East Longmeadow, MA
01028
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