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formulating with PVA
Whats the best way to solubilize PVA for a peel-off gel?
adding straight to water and heating to 80C?
or predispersing with Alcohol add adding below 30C? -
12 Replies
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My experience is to straight add to water and heat. Later you can add the alcohol and which is also very effective in de-aerating the PVA/water solution. Make sure you choose the right viscosity PVA, to start with you can check with SEKISUI. They have different grades, guess I used Selvol FA and the product came out pretty darn good.
Hope that helps. -
I add whole PVA and then heated up to 80.. but solving take about 1 hour.
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some times when I solve PVA in water, it becomes opaque. does any body know?
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I’m sorry, @nasrins, but I don’t see a question I can answer. What specifically do you want to know?
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why sometimes solubilize PVA in water becomes opaque and sometimes becomes clear?in same conditions
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If your PVA quality is consistent and from a reputed company then all I could think of is either a problem with water source or the utensils used to prepare the dispersion. Beats me for any other reason.
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This is a good time to point out some ways of thinking logically about troubleshooting.
Guiding principle: A batch made exactly the same way with exactly the same materials in the same place will turn out with the same properties and characteristics as the other batches made exactly the same way with exactly the same materials in the same place.This also means that when we see variability in a finished batch, that there MUST be a variability in either the raw materials, the processing, or the environment. Nothing happens magically.Problem: Variability in finished productSymptom: CloudinessThe way to isolate what’s going wrong is to start eliminating variables. For example, are you using pure water? How do you know it’s pure? And so on. -
what do you mean pure water? distilled water means…
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Great to see this thread getting so many information shared overnight;)
In my experience…I have seen that when I dissolve PVA in water and heat upto 80C, its hard to determine when to stop mixing…Again, I am more concerned when the formula moves to production.
So I did try to Pre-disperse PVA in Alcohol and that help using less energy and more clarity…….My only concern now is that PVA was not completely solubilized in Alcohol…Any comments?Milliachemist, what grade might have better solubility and better peeling? Any idea?
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@Chemwizard IIRC correctly it was Selvol Ultalux FA. You can find further information on their website mentioned below. I liked the end results though the final choice depends on the viscosity you are looking for. Since these are partially hydrolyzed grades you have to heat and hold for at least 30 minutes and thats what I did too.
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Truly pure water is hard to achieve - H2O by itself is somewhat corrosive.
Your water doesn’t need to be pure - just consistent, so that the pH, electrolyte level, TOC, etc. are kept constant and removed as variables in your search for what’s gong wrong. -
The important factor in dissoving PVA in water is formation hydrogen bond. with increasing temprature some bonds are breaked and solubilzing decreased, so its better to disperse PVA in cold water and then heating it slowy.
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