×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Hydrophillic coating on silicone

Hydrophillic coating on silicone

Hydrophillic coating on silicone

(OP)
I have a large number of silicone mouldings which are absorbing too much water.  The problem was due to using a silicone filled with precipitated silica rather than fumed silica.  Precipitated silica absorbs up to 8% water whereas the fumed silica absorbs only 1.5%.  I have tried drying the mouldings and painting with activated Silicone oil to reduce absorbtion but this did not work.  Does anybody know of a coating or process which could reduce the water absorbtion

RE: Hydrophillic coating on silicone

(OP)
I have been advised that I might try impregnating the surface with a hydrophillic wax as this might occupy the water absorbtion sites.  Does anybody know about these.

RE: Hydrophillic coating on silicone

Um.  I think you mean you want a hydrophobic coating, i.e. a coating which repels, or does not absorb, water.

Silicone oil is one of the most water-repellent substances around, but probably acts as a semi-solvent to your cured silicone rubber.

RE: Hydrophillic coating on silicone

(OP)
Yes.  I do need a hydrophobic surface.  My advice was to use a surficant which would attach its hydrophillic side to the silica filler and therefore present a hydrophobic surface.  I am not happy with the results so far and I prefer the silicone oil solution.  I have only tried one type of silicone oil.  Are there many different oils and might one have significantly improved results over another.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources