• If you are citizen of an European Union member nation, you may not use this service unless you are at least 16 years old.

  • You already know Dokkio is an AI-powered assistant to organize & manage your digital files & messages. Very soon, Dokkio will support Outlook as well as One Drive. Check it out today!


How to make the gel

This version was saved 13 years, 2 months ago View current version     Page history
Saved by Nancie Ravenel
on July 16, 2010 at 12:41:41 pm


TDS-237_Neutralizing_Carbopol_Pemulen_in_Aqueous_Hydroalcoholic_Systems--PC.pdf from Noveon includes a chart of indicating the amount of base needed to neutralize 1 part Pemulen to a pH of 7.

The master recipe Shelburne has typically used for the gel is

100 mL de-ionized water

10mL  base

1 g. Pemulen TR2

At Shelburne, we have used two alkaline compounds to make up the gel: triethanolamine (TEA) and a solution of 2% Tris(hydroxymethyl)aminomethane (TRIS) in deionized water.  Making the gel up with TEA using this recipe results in a gel with a pH of about 7.5-8, but measure the pH to make sure.


When this gel proves to produce an emulsion that is too aggressive for cleaning, the gel recipe is modified replacing some of the TEA with the solution of 2% TRIS, a weaker base than TEA.  This often results in a less aggressive emulsion cleaner even though the pH remains at 7.5-8.


The first step in preparing the gel is to mix the water and the base together.  Then Pemulen powder is added slowly with constant stirring.  While we initially had used a magnetic stirrer to create the gel, Laura Brill found that stirring the Pemulen powder into the water by hand using a miniature balloon wisk created a smoother gel from the beginning.  


In the course of preparing the gel, we have found that the pH of the gel falls about half a unit over night. This may be a result of the the manual method of preparation not allowing the polymer to quickly unfurl.




Comments (0)

You don't have permission to comment on this page.