Hi,
I am trying to build 10%w,v cylindrical PVA gel (PVA powder 99+% HYDROLYZED, Sigma-Aldrich 363146). I prepared 100 ml one successfully with stirring on the hotplate for 45 min and I applied 2 "freezing - thawing" cycles. It became a hard and good gel with white color at the end. I also tried 1 liter one with the same procedure but it is still fluidal (not hard like the previous one) with transparent color. The concentration, preparation procedures and the materials are totally the same. Should I stir more for the largest one? Does it mean the mixture is not homogeneous and the PVA didn't dissolve?
Thanks
Gizem, may be the solution was not good, or the freezing was too slow - the second sample was big. Can You use chemical methods? Like addition of boric acid, or partial oxidation with periodates? Tomek
Thank you for the answer. Because the phantom should be water equivalent or close to it, I should use only distilled water to solve the PVA powder. I use the gel(s) for medical purposes. Maybe I try to stir the mixture more than 45 min on the hotplate around 80 -90 degrees.
When You dissolve polymers it is always good to leave them overnight, so the polymer chains are in the equilibrium with solvent. Try to dissolve it in warm water and leave it overnight before freezing. Tomek
Hi,
You need to stir longer than 45 mins. For example, stir for 3 hours at 80 Celsius degrees and apply 3 freeze/ thawing cycles.
Hi , I want to prepare PVA-KOH,PVA-NaOH and PVA-Na2SO4 gel electrolyte. I tried to prepared it by heating and stirring both PVA and KOH / Na2SO4 ,but at the end PVA got agglomerated and there is no any adhesion in solution ??
you need to prepare pva in 70-80 c , or it may be expired so that it not dissolve
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