Greetings fellow researchers,
I am trying to adjust the pH of waterborne polyurethane that I bought for a research project. The problem is, no matter how much I tried, the pH only move a little bit. In pristine condition, its pH is 8.40. I want to lower it down to 7 or if possible, to 6.
Several things that I tried include 5% HCl, 5% citric acid, diluted HCl with pH ranging from 4 to 2.8. But, none of it seems to work. Research from google suggest that it might be a buffer effect. However, I am not sure. Even if it is, how can I adjust it?
Thanks.
It depends on how PUD is stabiliezed. In your situation probably polymer contains carboxylic groups turned into salt form with some kind of amine. Then it is in general bad idea to lower a pH because of high risk of destabilization of dispersion. I would suggest to look for sulfonate stabilized PUD. They are usually close to neutral and could maintain stability even in slightly acidic conditions.
Maybe you could try cationic PUD which already will have a pH value below
Dear Dr. Igors Sivacovs ,
Thank you so much for your suggestion. I will try that as soon as possible.
Best regards.
- Badges
- Science topic