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Synthalen W400 - low or high pH for increasing viscosity?
I took @chemicalmatt ‘s advice and got me some Synthalen W400 mainly for its suspension properties.
Matt, I know you recommended W600 but I ended up with a sample of W400 instead. Seems to not be much difference from what I’ve read, hopefully it works just as good.I am seeing contradictory information in the instructions provided with the W400. One graph shows viscosity increasing above pH of 6 while another shows the opposite.Can any one with experience working with this material tell me any of the following:
1. How does it behave with pH+viscosity?
2. What % do you usually use it at?
3. OK to drop in after surfactants and water have been mixed together?Thank you!
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2 Replies
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@GeorgeBenson the viscosity will peak at pH 6.5 - 7.0, the yield value (suspension factor) will be at maximum in that range too. This is a 30% solution so depending on what surfactants or electrolytes you have in the formula, and final viscosity, start at 4.00% (1.20% solids) and see what happens. It works best to add to water first, then add your surfactants, any alkali you may be using, then adjust pH at end. If you have a high pH surfactant system (decyl glucoside comes to mind) you may drop in later, but that is not advised. Also, like all acrylic rheology modifiers, go easy on the amphoteric surfactants. These are Zwitterions. 10% CAPB (30% soln.) will be fine.
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@chemicalmatt Thanks a lot! This is great information.
I am using a little CAPB but less than 10%. Out of curiosity why are amphoterics incompatible with acrylic rheology modifiers?
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