Fumed silica and yellowing?

I have been trying to make a clear lip scrub using a fumed silica gellant. However, all versions yellow significantly at 45C. I have a hunch it is the fumed silica, because I read somewhere that small sized silica can contribute to some yellowing in formulas. 

Has anyone experienced yellowing of a clear product with fumed silica? 

Thank you for your help. 

Comments

  • BobzchemistBobzchemist Member, PCF student
    Does it yellow without the fumed silica? What about using precipitated silica?
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
  • Chemist77Chemist77 Member, PCF student
    @Bobzchemist Are there any fixed standards to make a choice between the two?????? Or the formulation can accommodate both depending on the final properties desired???? 
    I have used Aerosil 200 in my lip gloss (clear) with good suspension of large glitter particles and it was based on Indopol H100 among other things from Scher esters. To tell you frankly it had a good suspension effect in that anhydrous formulation. 
  • BobzchemistBobzchemist Member, PCF student
    Precipitated silica is a scrub/abrasive ingredient. Fumed silica is a suspending/thickening ingredients, that is useless as a scrub, due to it's ultra-small particle size. By trying the formula with precipitated silica, it should be possible to determine if there's a problem with silica generally, or just with the fumed version.

    Precipitated and fumed, by the way, are referring to how the silica is manufactured.
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
  • Chemist77Chemist77 Member, PCF student
    edited August 2015
    @Bobzchemist Thanks that makes everything quite comprehensible. But that raises another question, do you need to suspend precipitated silica since it is just an abrasive???
  • kotkot Member, PCF student
    Can fumed silica be used in hair serums?
  • I purchased a quantity of fumed silica a few years ago and when we moved last year I found it again, portions of the top of the bag had turned quite a shade of deep yellow while the rest remained white so that may just the nature of the beast whether it is in a formula or left on its own over time.  I need to get rid of it but need to know where...

    David
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