Are you planning to use dispersoids in the Water-glycol solution or solute type thickeners?

Normally for solute types, carbohydrates like starch, proteins like collagen (gelatin) may be used. Natural gums derived from Vegetative produce are also an option.

For dispersoid types, micro-particulates of talc, dolomite, graphitic flakes etc. may be used, but the resulting emulsion must be stirred continuously to maintain homogeneity during testing.

Xanthan is the classic choice for water-based products. You need to check if it is still soluble in your mixtures...  If not, then try modified celluluose - CMC being the first choice. If that is not OK, there are other more hydrophobic  versions, such as ethyl cellulose (soluble in pure ethanol, I think) and HPMC.

I would prefer to use a solute type of thickener however dispersed one is also taken into account.

I have already tried cellulose however it has exhibited very strong shear thinning behavior and as far as I know Xanthan will show it too. 

Any other ideas?

Thank you very much for your contribution.

Szymon Bernat:

I don 'know if this Polyalkylene glycols (PAG) mix  concentrations shown below would help you in your search. But you could found more information in STLE National Meeting. May 2011. Richard Butler & Dr. Govindlal Khemchandani

Typical Traditional Synthetic Fluid Formulation Using Water Soluble PAG

Component Amount (wt %)

• Polyalkylene glycol 5-15

• Phosphate ester (or fatty acid) 0-7

• Borate corrosion inhibitor 0-5

• Carboxylate corrosion inhibitor 10-20

• Triethanolamine 10-15

• Biocide 2-4

• Water 45-60

See link below:

 http://www.dow.com/ucon/osp/pdf/stle_innovations_pag_lubricants_052011.pdf

My best regards

Dear Carlos E Losada,

I think that in this case they use high molecular weight PAG that is viscous by itself. The rest of additives are mostly antiwear, dispersants and corrosion inhibitors and will not increase viscosity so much. 

My best regards

Oh, OK, yes everything I suggested will be shear thinning. That is usually an advantage. Dispersion thickeners I know less well. How about microcrystalline cellulose, like Avicel from CP Kelco? These products give a much "shorter", less shear thinning texture. 

Yes, polyalkylene glycols the best water-soluble thickeners. PAG thickeners provide Newtonian behavior W/G fluids, i.e. fluid viscosity  changes very little with shear, and independent  of shear rate....

Dear Szymon Bernat.

Ok. I understand your point. In that case the suggestions from Alan Parker seems to be worthy to try. Or in the pass some Engine Oil manufactures have been using Polysobutylene (PIB) and polyester (PE) as thickener...

Just a note:  In my experience if you add and additive (polymer) "thickener" to Engine Oil (for example), in the end the viscosity could be decrease by degradation of macromolecules of the additive in the presence of mechanical shearing device during the service of equipment.

My best regards

I've tried to do something similar and found that all water based high viscosity solute type viscosity modifiers showed extreme shear thinning.

The only thing I found that worked in a tribological contact was sugar solutions. Golden syrup for example worked amazingly and gave thick films even at low speeds.