Dispersant for Nano Particles

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christensent

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I'm working on getting absolute minimum stiction in a high pressure hydraulic off-road suspension system with u-cup seals. I've had good luck with polar boundary film additives but also want to try adding nano particles of MoS2, WS2, etc. in 70nm size (I realize larger particles are mostly snake oil but small particles might be quite helpful according to some research - understand it is very likely to do nothing just want to experiment).

But, I need a good dispersant to keep it from clumping and keep it in solution longer. I figured polyisobutylene succinimide (PIBSI) would be a great choice, especially factoring in my need for nitrile and urethane seal compatibility, but it's very hard to buy straight PIBSI. The only real options are sampling on Alibaba, which I've tried but am having long delays in shipping and I'm not confident it'll ever come.

Are there any good dispersants I can actually buy as a consumer with no business entity? I need some concentrate as I don't want to dilute my base oil more than a few percent.

I've used some consumer grade snake oil additives from the auto store before in this system (not so much as a dispersant, just in general), and they have sludged, so I'm very hesitant to use anything like that unless they're extremely known to be nothing but a highly stable dispersant.
 
christensent said:
I'm working on getting absolute minimum stiction in a high pressure hydraulic off-road suspension system with u-cup seals. I've had good luck with polar boundary film additives but also want to try adding nano particles of MoS2, WS2, etc. in 70nm size (I realize larger particles are mostly snake oil but small particles might be quite helpful according to some research - understand it is very likely to do nothing just want to experiment).

But, I need a good dispersant to keep it from clumping and keep it in solution longer. I figured polyisobutylene succinimide (PIBSI) would be a great choice, especially factoring in my need for nitrile and urethane seal compatibility, but it's very hard to buy straight PIBSI. The only real options are sampling on Alibaba, which I've tried but am having long delays in shipping and I'm not confident it'll ever come.

Are there any good dispersants I can actually buy as a consumer with no business entity? I need some concentrate as I don't want to dilute my base oil more than a few percent.

I've used some consumer grade snake oil additives from the auto store before in this system (not so much as a dispersant, just in general), and they have sludged, so I'm very hesitant to use anything like that unless they're extremely known to be nothing but a highly stable dispersant.
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If the particles are really that large then no surfactant or dispersant is going to keep them in suspension.

Plus those products are used in very small quantities, typically well below 1%. You’re not going to dilute the base oil in any way.

And I’m not sure what you’re asking in regards to a highly stable dispersant? Please explain this question. I worked with surfactants and dispersants for years in a previous career.
 
kschachn said:
If the particles are really that large then no surfactant or dispersant is going to keep them in suspension.

Plus those products are used in very small quantities, typically well below 1%. You’re not going to dilute the base oil in any way.

And I’m not sure what you’re asking in regards to a highly stable dispersant? Please explain this question. I worked with surfactants and dispersants for years in a previous career.
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By stable, I mean it must not swell or interact with my seals (worried about this with stuff like amine based dispersants), and also needs to not break down, sludge, etc. under pressure and shear seen in a hydraulic damper.

Yes I would be using a fraction of a percent of nano-particle and at most 1-2% dispersant. The concern on dilution would be if the product already is only 1% dispersant, then I'd have to run the product as my primary oil. I do not want something like that.

I do not need it to remain in suspension indefinitely as it will quickly get shaken up in application, and I know I will never achieve true indefinite dispersion. Just something to help the process, and especially help it not clump. I've had some luck with larger PTFE particles in experiments for this application and want to give it the best shot with a good dispersant.
 
I've found the smoothest operation and least stiction in motorcycle forks using Motul Factory Line Fork Oil.
I don't know the specifics of what you're putting fluid in, but for off the shelf, this is very good.
 
christensent said:
I'm working on getting absolute minimum stiction in a high pressure hydraulic off-road suspension system with u-cup seals. I've had good luck with polar boundary film additives but also want to try adding nano particles of MoS2, WS2, etc. in 70nm size (I realize larger particles are mostly snake oil but small particles might be quite helpful according to some research - understand it is very likely to do nothing just want to experiment).

But, I need a good dispersant to keep it from clumping and keep it in solution longer. I figured polyisobutylene succinimide (PIBSI) would be a great choice, especially factoring in my need for nitrile and urethane seal compatibility, but it's very hard to buy straight PIBSI. The only real options are sampling on Alibaba, which I've tried but am having long delays in shipping and I'm not confident it'll ever come.

Are there any good dispersants I can actually buy as a consumer with no business entity? I need some concentrate as I don't want to dilute my base oil more than a few percent.
Click to expand...
What is your definition of "stiction" and where would this stiction be a problem?
 
MolaKule said:
What is your definition of "stiction" and where would this stiction be a problem?
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In this case, stiction is the breakaway-friction induced by the back-to-back urethane u-cup seals on the piston (completely separating the upper and lower chamber of the hydraulic cylinder damper), which are operating at about 350PSI steady state (it is an air spring so it sits at this pressure even with no motion). This friction effectively locks out the suspension until force is high enough to break the piston free and is a significant contributor to ride quality on the suspension.
 
christensent said:
In this case, stiction is the breakaway-friction induced by the back-to-back urethane u-cup seals on the piston (completely separating the upper and lower chamber of the hydraulic cylinder damper), which are operating at about 350PSI steady state (it is an air spring so it sits at this pressure even with no motion). This friction effectively locks out the suspension until force is high enough to break the piston free and is a significant contributor to ride quality on the suspension.
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I am having trouble visualizing your system, but most hydraulic fluids have dispersants, friction modifiers, and anti-wear chemistry that should be sufficient.

I don't see any advantages adding nanoparticle FMs.
 
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So is this for a mountain bike or dirt bike or something along those lines?

You’ll likely not be able to keep the particles in suspension as mentioned above. I’m not sure if adding any particle type material would benefit you in reducing stiction.

Do you have a test rig or anything to evaluate how your fluid is performing?

High end shock fluids are often a low viscosity PAO hydraulic fluid. You can get more exotic and look at things like esters or alkylbenzenes which may affect your seals but also have different damping and frictional effects.
 
Why the reluctance to state the actual vehicle?
This is like asking what fluid for my transmission and when asked what transmission in what car, the reply is "an automatic". 🤷‍♂️

Off the shelf fluids are as good as you will get to overcome "stiction" unless maybe you go to NASA for some magic potion. If there was some additive that made things better, you'd be reading about it on the motorcycle and 4 wheeler forums.
 
MolaKule said:
@christensent

Suspension fluids (a special hydraulic fluid) such as

https://amsoilcontent.com/ams/lit/databulletins/g1663.pdf

have dispersants, friction modifiers, seal swell chemistry, anti-corrosion, and anti-wear chemistry in a complete formulation.

@Pablo
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That is the base oil I am using. It is quite good on friction, but I can easily make it perform much better on my test rig by adding things like CAT hydraulic additive (stiction eliminator) which is basically just 3-hydroxy-2,2-bis(hydroxymethyl)propyl oleate according to MSDS.

Since I've had good luck with PTFE in this system, was interested in trying adding more nano particles too (again, totally aware nano particles may be worthless in this system, but I doubt it can hurt and it has seemed to help before).

Perhaps the base oil already has plenty of dispersants. I just today thinking about this realized that the oleate I'm adding may act as a decent dispersant anyways!
 
CleanSump said:
Why the reluctance to state the actual vehicle?
This is like asking what fluid for my transmission and when asked what transmission in what car, the reply is "an automatic". 🤷‍♂️

Off the shelf fluids are as good as you will get to overcome "stiction" unless maybe you go to NASA for some magic potion. If there was some additive that made things better, you'd be reading about it on the motorcycle and 4 wheeler forums.
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I work on super custom suspension things and usually don't mention the "what" as I usually find it to act as a distraction. It shouldn't matter, the topic is how to reduce stiction on a urethane U-cup piston seal in a hydraulic cylinder. It's a home-made custom application.

As mentioned above, just adding a CAT additive has already far outperformed any off-the-shelf suspension oil I have tried (have experimented with half a dozen or so products on a test setup). I'm not going to claim I outperform every off-the-shelf fluid, can't try them all.
 
christensent said:
That is the base oil I am using. It is quite good on friction, but I can easily make it perform much better on my test rig by adding things like CAT hydraulic additive (stiction eliminator) which is basically just 3-hydroxy-2,2-bis(hydroxymethyl)propyl oleate according to MSDS.

Since I've had good luck with PTFE in this system, was interested in trying adding more nano particles too (again, totally aware nano particles may be worthless in this system, but I doubt it can hurt and it has seemed to help before).

Perhaps the base oil already has plenty of dispersants. I just today thinking about this realized that the oleate I'm adding may act as a decent dispersant anyways!
Click to expand...
Yes that fluid looks to be a common pentaerythritol ester acting as a friction modifier.

This is likely a much easier and more straightforward path than adding solid lubricants to another fluid. Actually a high quality synthetic compressor oil likely would be great in this application as many are blends of esters and pao.
 
@christensent

"Perhaps the base oil already has plenty of dispersants. I just today thinking about this realized that the oleate I'm adding may act as a decent dispersant anyways!"

The CAT component is an ester similar to TMP.

I recommend you contact a formulator familiar with suspension fluids and lubricant chemistry since no one is going to formulate a fluid for you over the internet, especially if there is IP involved.

Since you have been given various helpful comments, we will close this thread.
 
kschachn said:
This reluctance to give actual information is somehow common to these mystery threads that get posted from time to time. The OP says it would be a "distraction" when in reality it would be just the opposite, and by not stating particulars this causes the distraction.
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Ok, if it is of any help, it is a custom homemade dual-chamber air strut on a modified Jeep Wrangler utilizing back-to-back u-cup piston seals.
 
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