Yes. There are too many examples to provide, but a very common one is that the G' plateau is proportional to the molecular weight between crosslinks.

Take a specific example: The new BYK-410 & 411 for solvent based formulations. Produced by BYK Chemie.

Based on an urea polymer that show what BYK describe as being "Associativity" as seen so often in now days, but exclusively in water based systems.

They also have a water based version B-421 if I remember well that I introduced in one of my novel formulations last year.

Good seach! There ain't much in solvent based systems.

Very, very poor.

Pierre.

rheology of polymers is simply the operating conditions that must be provided to the polymer to be cured for example tc90 is the temperature of curing rubber to about 90% ML is the minimum torque which reflects minimum viscosity of the mixes and is taken as a measure of filler–filler interaggregate formation, MH is the maximum torque which reveals the cross-link density of the fully vulcanized rubber.

Oh! You again, Miss. or Mme. Abeer? Good day to you!

I think I remember exchanging a few concepts with you a few months back.

But it could be someone else, as well in another group.

Hey! One thing for sure though, is that you work in the specialty of "Vulcanized Rubber"?

I'll have a good little question directly related to this specialty if you can help me?

But the photos related to that question are in my laboratory while I'm at home presently.

I am preparing my yearly R&D reports for government grants presently and I will have time to come here and post these photos I mentioned.

Frankly, I don't feel comfortable with your assertion "rheology of polymers is simply".

But allow me to believe that you translated this phrase in English first in your mind to type it down on your computer? This is much possible while you replied someone else?

Because in my view, rheology is a science within physical chemistry.

Maybe that within the specialty where you practice, it defines itself only on this physical behavior (Cross-Linking of the rubber insaturation) but in so many other physical behaviors, rheology also exist.

Was the "Cassons Curves", the yield point of a given polymers only determined in a semi-solid or semi-liquid state on a so-called "Brabender torque" laboratory instrument?

What about the Brookfield rotational planetary viscometer?

How should I qualify a liquid that gets less viscous when it flows faster?

And on the contrary, how should I qualify a liquid that gets more and more viscous as it flows faster and faster? Ketchup or mustard maybe?

Ah nah! It just ought to be that you had a hard time to explain the rheological changes that occurs in rubber while the cross linking chemical reaction goes on! It's impossible that you are unaware of the other rheological behavior of most if not all liquids or liquid blends.

The "Big Question": What solvent would be powerful enough to partly (For the least...) solubilize or may I rather say "Coalesce" tire rubber? I have been working quite a bit on economical tire shine formulations last month.

In one instance, we wanted a little more performing formulation that would bare a certain amount of cationic emulsion. (Many micro-emulsions are clear as water).

My basic formulation was water based and baring a good amount of water soluble solvents like propylene glycol, isopropyl alcohol and of course, a non-ionic surfactant of an HLB of ~ 16 to protect the translucidity of the silicone emulsion. So that the customer has the impression to work only with thicken water.

A matter of environment in Canada...

Ok! I had 2 micro-emulsions. One who was a some ~ 30% solid amino-functional silicone (Maybe in the type the of the Dow Corning DC-531 if I remember well the grade) which was first hydrolyzed in water by a weak organic acid (As described by Dow C.) to later be micro-emulsified in water at an acidic pH because of obvious reasons! However, this type of "Alkoxy-blocked amino-functional reactive" silanol are not so much glossy. According to Dow C. and the technologists within that field.

So, I had another micro-emulsion for which there was not doubt that it was a simple polydimethyl siloxane and non-functional in any way. A silicone oil may I state?

And it was micro-dispersed by the tri-ethanol amine salt of a docecylbenzene sulfonate salt.

Pure anionic micro-emulsion! OK ! Now we're ready to describe the goof (Error) I made!

And oh! A very slight amount of tetracylcycosilioxane is present within the micro-emulsion to reduce the viscosity of the some 25,000 cst polydimethylsiloxane...

May we note that it is known that this cyclic silicone starts degrading at pH lower than some 5.XX?

This, as published at large on the Internet.

Because the 1st micro-emulsion sample I obtained for this project was the cationic one at pH ~ (4.5-5.0), I decided to use a tallow amine 40 ethoxylate ionic surfactant neutralized by lactic acid down to a pH of some 4.5. I first introduced a very slight amount of xantham gum to thicken up my water.

Then introduced the glycols(Plus PEG 400 polyethylene glycol) and the alcohol followed by the Tallow amine 40 ethoxylates and pH adjustment by the lactic acid to a pH of some ~4.0...

Stirred well to get the translucidy and than threw in the micro-emulsion in!

Do not forget that I planned this cationic formulation to introduce the cationic amino-functional micro-emulsion!!! But when time came to prepare the other one for the German anionic silicone micro-emulsion, I did not make any changes to the cationic nature of my water based mixture!

WORST! I brought down the pH to the same low value of some ~4.0!

Endangering the stability of the anionic silicone oil emulsion!

I guess that from one day to another, I was a little sleepy?...

Anyway, mixed well the formulation to reach the clarity of the mixture and applied it on the laboratory tire.

The day after: It was so ugly! The gloss was uneven on the tire.

Very glossy here but matte over there...

Anyway, my boss had my other cheap formulation to satisfy his customers? Good!...

So, I went to wash my laboratory experimental tire in the company's garage.

Brought it back in my laboratory and prepared my daily report.

The day after...

The day after, my boss comes in the lab and asks me: "Pierre, have you seen the super glossy streaks on the tire over there"?...

We tried to get rid of what appeared to be as drips of the erroneous formulation I applied the day before, but never been able to rid the tire of these tracks of dry drips of that formula!

And they are still on that tire! As dry as the tire can feel!

It just does not go away.

Even if I try to wipe them off with methylene chloride, (Or toluene) the most powerful solvent we can dream about. That remains there and are super hooper dooper glossy.

They are nagging me! Please help! This tire is torturing me!

I see them in my soup, have nightmare about them and just can't figure out how they remain there for ever glossy! The silicone seems to be adsorbed onto the surface because the tracks of these glossy drips show a higher hydrophobicity than the surrounding rubber surface.

Do you know of any solvent that can partly dissolve or "Coalesce" vulcanized rubber?

I already tried the most potent ones I think, tetraline and decahydronaphtalene!

Tomorrow if I have time, I'll post the photos of these glossy steaks that the drips of that erroneous formulation done to this tire. Now time for the nightmare glossy tire drip torture.

Bye now!

I'm so very sorry but the day passed away so swiftly and some workers in production told me about the holiday next Monday. Forgot to upload these photos from my laboratory computer.

I was so absorbed in the resaction of my yearly R&D reports.

I thought of thephotos while I was already on the road, coming home.

Posting the photos will go to next week. Maybe tuesday or so.

Anyhow, I guess that peoples on this website do not consider this phenomenon as much interesting.

It's only goal is to bring work and money to workers.Nothing "Glorious".

And it may well be complex enough to dumpt that project this year.

A liquid organic solvent strong enough to play the role of a coalescent toward vulcanized rubber; -Never been seen or so very rarely seen. I ain't much confident into this.

And my boss looks as if he's got quite a large list of project for next year.

One is attacking and stripping metalic magwheel with either an alkali alkoholate or alkoxylate at some (100-120) centigrades! This guy's going a bit "Zaza"?

Anyhow, if anybody would have any suggestion about a poorly volatile or non-volatile powerful diluant that attack partially vulcanized rubber, please let me know.

Be back later one.

Good holiday!

Pierre.

Yes

Oh? India? It's been a few gnerations that this nation got pretty much specialised in rubber technology.

However, I see on your description that it isn't much of your "Specialty" as such.

Anyhow, I'm home and the photos of the phenomenon I mentioned are on my laboratory computer.

And the "Etched" glossy strips of the automobile tire are also in my lab while I'm home for the weekend.

Coming here this weekend made me realise that I cannot post a photo to better describe the case!

I think that I will pass a comment to the website that we should be able to add photos or documents for better understanding of a given challenge. I even wonder if there is any facilty on this website to transfer a file (Document of photos & screen captures) for everyone to know the facts.

Else, I'll have to post the photo somewhere else.

Dunno yet.

Pierre.

Follow this link it could be useful and satisfies all your needs,questions download the pdf file and read it carfully ..........good luck

http://www.wernerblank.com/pdfiles/rheology.pdf

First; thank for the "Rheology.pdf file Mme. Abeer. It was one with the best structure I've ever seen!

This confirms that I had only an impression that you meant that rheology applies solely to the semi-liquids.

I shall state that all of what is mentioned in the Rheology PDF file, was already known to me.

And in some cases, with much more deepness. It is an oversight more than anything else.

Still, a well structure presentation to an administrator who wonders what we're working on.

For instance, they do not explain how to test the "Thix Index" on a Brookfield viscometer.

One number which come the division of a 10 fold dial reading because of the logarithm relation?

Pretty uneasy to obtain reproductivity anyhow, for some thixotropic values.

It works well for certain ranges of thixotropy but not all!

The other interesting thing in this document was the mention about the Tg determination by viscosity.

Though, he didn't elaborate much. If one can operate in a diluted solution.

I'll have to carry a few searches on this...

In any events, I thank you because as I went to the homepage, I discovered a lot of things that man has done within its career! Have you seen all the patents he was involved with? Looks like a good man!

Anyway! I have found a way to share my files easily without the need of this website.

I stored files on a FTP server. I can either request a password or offer the file freely.

I'm still home without my tire photos but have some technical archives on my puter here.

I have the Alox-2211Y I talked about. Even though it is not much of your specialty and belong to another very different question I asked somewhere else, I want to see if it'll work...

I took good note that you sent me the rheology.pdf by an HTML link, & I think I'll do the same!

Too bad I don't have the photos on my puter here at home.

Let see if my HTML link will work:=>http://www.4shared.com/document/HfzdB6KB/Alox-2211Y.html

Scroll down that webpage a little until the link for downloading the PDF file shows up.

Click on the command download and wait for a while until the website says the file is ready to be downloaded. Otherwise, it would not be free.

I'll try that myself.

Pierre.