DubaiAmateurRocketry
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how to determine average mw of a polymer ?
I just received a KG of HTPB with MW 2300-2800.
a 500 is a big difference that can cause different mechanical properties if i cured it with 1:1 2200 or 1:1 2700 with MDI. If i do not know the mw of
my HTPB.
How shall i determine the average mw of my HTPB then ?
[Edited on 4-10-2013 by DubaiAmateurRocketry]
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bfesser
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"KG" (wrong) = kg
MW = molecular weight (every chemist knows this)
HTPB = <a href="https://en.wikipedia.org/wiki/Hydroxyl-terminated_polybutadiene" target="_blank">Hydroxyl-terminated polybutadiene</a>
<img src="../scipics/_wiki.png" />
MDI = <a href="https://en.wikipedia.org/wiki/Methylene_diphenyl_diisocyanate" target="_blank">Methylene diphenyl diisocyanate</a> <img
src="../scipics/_wiki.png" />
What equipment and instrumentation do you have at your disposal? If I recall correctly, you can use something as simple as the viscosity of a
solution to get a crude figure, or something as complex as a multi-instrumental analysis. (I'm out at the moment, but will refer to my polymer texts
when I get home.)
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DubaiAmateurRocketry
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Quote: Originally posted by bfesser  | "KG" (wrong) = kg
MW = molecular weight (every chemist knows this)
HTPB = <a href="https://en.wikipedia.org/wiki/Hydroxyl-terminated_polybutadiene" target="_blank">Hydroxyl-terminated polybutadiene</a>
<img src="../scipics/_wiki.png" />
MDI = <a href="https://en.wikipedia.org/wiki/Methylene_diphenyl_diisocyanate" target="_blank">Methylene diphenyl diisocyanate</a> <img
src="../scipics/_wiki.png" />
What equipment and instrumentation do you have at your disposal? If I recall correctly, you can use something as simple as the viscosity of a
solution to get a crude figure, or something as complex as a multi-instrumental analysis. (I'm out at the moment, but will refer to my polymer texts
when I get home.) |
Thank you very much, i would like to know both ways to figure out the mw.
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Dany
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See
http://en.wikipedia.org/wiki/Gel_permeation_chromatography
Dany.
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BobD1001
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Mind PMing me the source for the HTPB? I am a model rocket enthusiast, and make my own composite propellants. I have been using PBAN, however HTPB is
supposedly significantly easier to work with, and a much faster cure rate without the need for a heating chamber.
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DubaiAmateurRocketry
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| Quote: Originally posted by BobD1001 | | Mind PMing me the source for the HTPB? I am a model rocket enthusiast, and make my own composite propellants. I have been using PBAN, however HTPB is
supposedly significantly easier to work with, and a much faster cure rate without the need for a heating chamber. |
This is the company
http://www.qilong-chem.com/en/product/html/?99.html
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bfesser
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New suggestion:
http://www.qilong-chem.com/en/page/contact/contact.php
Ask for Certificate of Analysis.
Next time, give all relevant details when asking a question; it makes all our lives easier.
[Edited on 4.10.13 by bfesser]
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bfesser
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Thread Moved
4-10-2013 at 09:44 |
PHILOU Zrealone
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Osmometry, differential tonometry also comes to mind to mesure average MW of a polymer.
Eblioscopy and cryoscopy would be too unsensitive because the weakest point is precise temperature measurements and temperature difference will be
very small due to large MW.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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