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Viscosity Modifiers II #5131335 06/11/19 11:57 AM
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MolaKule Offline OP
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There are three (3) key features of polymer viscosity modifiers, specifically VII VM's:


Name those three key features:

1)

2)

3)


This question is open to ALL.


"You ... sadist," said Mr Cummings, "you try to make people think." Ezra Pound (1885-1972)
Re: Viscosity Modifiers II [Re: MolaKule] #5132150 06/12/19 09:25 AM
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They help reduce a lubricants viscosity change at high AND low temps



Re: Viscosity Modifiers II [Re: MolaKule] #5132180 06/12/19 10:04 AM
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MolaKule Offline OP
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Originally Posted by 53 Stude
They help reduce a lubricants viscosity change at high AND low temps

They do modify the rate of change in viscosity verses temperature.

I'll give a Hint to help things along. Please identify the other two features:
Originally Posted by MolaKule
There are three (3) key features of polymer viscosity modifiers, specifically VII VM's:


Name those three key features:

1) thickening efficiency

2)

3)


This question is open to ALL.


Last edited by MolaKule; 06/12/19 10:21 AM.

"You ... sadist," said Mr Cummings, "you try to make people think." Ezra Pound (1885-1972)
Re: Viscosity Modifiers II [Re: MolaKule] #5132279 06/12/19 12:20 PM
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CR94 Offline
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They should be cost-effective.
They should be free of characteristics that would make it difficult to meet other requirements.
They should be as nearly shear-stable as possible.


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Re: Viscosity Modifiers II [Re: MolaKule] #5132288 06/12/19 12:31 PM
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rollinpete Offline
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improved viscosity index,
enhanced thickening efficiency,
and appropriate shear stability.

So viscosity modifiers help keep the oil at it's original viscosity through out it's career as a lubricant?


Pete.

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Currently under the influence of oil shocked2

Re: Viscosity Modifiers II [Re: MolaKule] #5134143 06/14/19 03:20 PM
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MolaKule Offline OP
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Thanks to all who responded and since this question was open to ALL, I thought there might be more responses.

Congratulations to rollinpete who supplied all three answers.

Thickening efficiency, the viscosity-temperature relationship, and shear stability are all Key features of Viscosity Index Improvers.

No one VI Improver can deliver optimum performance in all three areas, which is why new VII's have been developed which enhance overall polymer performance.

For example, the PAMA-OCP VII chemically "grafts" PAMA molecules onto the OCP backbones to improve the performance in all three areas.


Last edited by MolaKule; 06/14/19 04:17 PM.

"You ... sadist," said Mr Cummings, "you try to make people think." Ezra Pound (1885-1972)
Re: Viscosity Modifiers II [Re: MolaKule] #5137596 06/18/19 02:27 PM
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What about shear thinning?


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Re: Viscosity Modifiers II [Re: DriveHard] #5137889 06/18/19 08:38 PM
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MolaKule Offline OP
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Originally Posted by DriveHard
What about shear thinning?


Thickening efficiency, the viscosity-temperature relationship, and shear stability are all Key features of Viscosity Index Improvers.


"You ... sadist," said Mr Cummings, "you try to make people think." Ezra Pound (1885-1972)
Re: Viscosity Modifiers II [Re: MolaKule] #5173476 07/29/19 04:54 AM
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I was under impression that too much vm is bad and it shears or burns or makes sludge or something ...
Sounds like they are as bad as I thought !?

Re: Viscosity Modifiers II [Re: OilUzer] #5174344 07/29/19 09:38 PM
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Originally Posted by OilUzer
I was under impression that too much vm is bad and it shears or burns or makes sludge or something ...
Sounds like they are as bad as I thought !?


Why would a formulator put too much VII in a formulation?

You only insert as much VII as is necessary to achieve your viscosity target.

If you can't achieve a viscosity target using the prescribed amount of VII then you need to change the viscosities of the base oil mix to get there.

Last edited by MolaKule; 07/30/19 12:05 AM.

"You ... sadist," said Mr Cummings, "you try to make people think." Ezra Pound (1885-1972)
Re: Viscosity Modifiers II [Re: MolaKule] #5174476 07/30/19 02:38 AM
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Originally Posted by MolaKule
Originally Posted by OilUzer
I was under impression that too much vm is bad and it shears or burns or makes sludge or something ...
Sounds like they are as bad as I thought !?


Why would a formulator put too much VII in a formulation?

You only insert as much VII as is necessary to achieve your viscosity target.

If you can't achieve a viscosity target using the prescribed amount of VII then you need to change the viscosities of the base oil mix to get there.


Thanks for your reply.

I didn't word it correctly. By too much vm I meant if the gap is wider like in case of 5Wx30 vs. 10Wx30 ... 5Wx30 must use more vm compared to 10Wx30 and that's not desirable (i.e. relatively "too much vm") and IF you can live with 10W cold temp rating, best is to use lower vii oil ...
However after your reply, I recalled that SonOfJoe also saying that VMs aren't bad or as bad as people think or something to that effect.

Re: Viscosity Modifiers II [Re: OilUzer] #5174480 07/30/19 03:16 AM
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Originally Posted by OilUzer
I was under impression that too much vm is bad and it shears or burns or makes sludge or something ...
Sounds like they are as bad as I thought !?


Correction:
Meant to say Sounds like they are not as bad as I thought.

Re: Viscosity Modifiers II [Re: OilUzer] #5175177 07/30/19 08:25 PM
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MolaKule Offline OP
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Originally Posted by OilUzer
Originally Posted by MolaKule
Originally Posted by OilUzer
I was under impression that too much vm is bad and it shears or burns or makes sludge or something ...
Sounds like they are as bad as I thought !?


Why would a formulator put too much VII in a formulation?

You only insert as much VII as is necessary to achieve your viscosity target.

If you can't achieve a viscosity target using the prescribed amount of VII then you need to change the viscosities of the base oil mix to get there.


Thanks for your reply.

I didn't word it correctly. By too much vm I meant if the gap is wider like in case of 5Wx30 vs. 10Wx30 ... 5Wx30 must use more vm compared to 10Wx30 and that's not desirable (i.e. relatively "too much vm") and IF you can live with 10W cold temp rating, best is to use lower vii oil ...
However after your reply, I recalled that SonOfJoe also saying that VMs aren't bad or as bad as people think or something to that effect.


I believe Solarent made that statement:

Viscosity Improvers are not bad

Anyway, after re-reading your original post I think I may see what you were pointing to.

VII's in engine oils are, in chem-speak, polymers. And polymers are subject to degradation and oxidation as any other additive component. The rate of degradation is highly dependent on molecular weight and the polymer's molecular structure, and engine condition and operation.

Another reason for not using any more VII than necessary is the cost, since VII's are more expensive than base oils, so it is desirable to use as little VII as possible to achieve the 100C kinematic viscosity.


Last edited by MolaKule; 07/30/19 08:26 PM.

"You ... sadist," said Mr Cummings, "you try to make people think." Ezra Pound (1885-1972)
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