Cloud point with non ionic surfactants.

EliEli Member, PCF student
edited June 2014 in Formulating
Hello, 

I have a problem with a detergence formula that has a non ionic surfactant and an optical brightener. The problem is that when we are heating the solution until 40ºC to solve the optical brightener (solid) the transmittance worsen with the temperature. I have read about the cloud point, specially with non ionic surfactants. Any idea how to prove that this is the phenomenon that the solution is going through? I tried to raised the temperature a lot to see if phases separate but nothing happens. And if this would be the case, how can i change the could point of a solution ? THanks !

Comments

  • Chemist77Chemist77 Member, PCF student
    Is it not possible to pre-dissolve this optical brightener and then incorporate it in the formula? Secondly why dont you try heating this surfactant separately just to check if it is clouding out of the surfactant, just for confirmation. Last but not the least with higher salinity we can tweak the cloud point but again I am not sure if this would be standard for 100 outof 100 cases. It may vary from one situation to another, better to optimize the processing for best results.
  • EliEli Member, PCF student
    Thanks @milliachemist! This process doesn't happen in the final formula but in the dispersion phase with a premix base. We don't want to store the slurry (microbial problems) of the optical brightener but the final powder solved in a premix soap base with the optical+surfactant+ Pdiol. To this premix solution it will be added the rest of the raw materials. Correct me if I am wrong but if the optical particles are supposed to stay inside the micelles how can I pre-dissolve it without the surfactant? l heated the surfactant separately but it doesn't seem to show any change at all.. The only worsening effect of the transmittance is when it is in solution with the optical. Another hypothesis was that the optical in powder would have calcium or magnesium that will affect the solubility in the premix base, because cleaning it before with EDTA sometimes it works. Only sometimes... I can't figure out what else could be worsening the solubility and transmittance.
  • Chemist77Chemist77 Member, PCF student
    Well what I understand is that probably the OB is the one giving problems, is it not possible to ask your supplier for more elaboration on this. You might be advised for another brightener and that suits your current recipe. If there was a problem with your surfactant it would show but when you mix everything then only you are having trouble. EDTA might be a help as you pointed out but still I suggest you check with your supplier for perfect solution.
  • Chemist77Chemist77 Member, PCF student
    Eli can you please tell me which surfactant you hv used in your formula?????
  • EliEli Member, PCF student
    Thanks @milliachemist. The surfactant is polypxyethylene C12-C15 ether. I found it's cloud point at 1% around 48 and 52 C. But I don't know how much it changes when it is in pdiol instead of water.
  • Chemist77Chemist77 Member, PCF student
    Eli think you need to do some knock out trials to determine which of the ingredients is affecting the H bonding of your surfactant and throwing it back into the solution. Anything apart from high temperature of course, that affects the H bonding is going to hurt the surfactant solution.
    I hope you can have some better inputs on this but this is the best I could think of.
  • EliEli Member, PCF student
    Thanks a lot @milliachemist. I am waiting for the supplier answer but I will start the trials. !
Sign In or Register to comment.