What do you mean by Formula molecule? Do you want to measure VA content? I suggest you to use Gel Permeation Chromatography for determination of molecular weight while FT-IR and NMR for structure and functional group

Please explain further

Thanks for both response. Actually I bought EVA from sigma,But they not provide me the formula molecule ,MW even the full structure. They said it confidential.I need all the data in order to use it for my simulation purpose. I know the VA content which is 25%VA and the rest is ethylene...Form the GPC we can find the everage MW right? How about the Molecular Formular? Isn't possible to use CHNOS equipment?Many thanks

From reading your question, do you want an answer such as ethylene-500-vinyl acetate-125? "Formula molecule" is not a common term.

What you ask will be very difficult to determine as most EVA will be a confidential mixture of several monomers, surfactants, initiators, inhibitors and co-solvents. The staging of monomer addition can also change the final properties.

It may be best to determine molecular weight and work backwards from the known VA content.

These instruments can describe the polymer but they won't tell you the full composition. A person skilled in polymer chemistry could reverse engineer a polymer with only some of these.

Differential scanning calorimetry (DSC): the glass transition temperature (Tg)

Gravimetric analysis: polymer solids content

GC-MS: solvent and co-solvent (also some information on monomers if an expert in the art)

GPC or SEC: polymer molecular weight

Light scattering: particle size

IR: functional groups of special monomers

NMR: possibly can give monomer ratios

MALDI-TOF-MS: advanced polymer characterization

Elemental analysis is unlikely to be useful.

Thank you Mr Geoffrey Burrell

I bought EVA from sigma which content of 25%VA and 75% of ethylene. I need the informations such as MW,density and the formula structure. I need to characterize the EVA sample in order to used it for my simulation.

I have been told by someone by using elemental analysis can directly find the percent of each atom in the sample, after that by dividing all component by it JMR can directly find the MW. So if this is wrong, I will not proceed to do the elemental analysis.

I will try to use GPC or SEC for MW..

Many Thansk

I think you should do all testing listed by Geoffrey Burrell.

Usually the properties of polymer will related to the structure which also related to movement of chain, molecular weight, branching, bulk functional group and e.t.c

May I know about your research? Do you use this EVA as pour point depressant?

Dear Dr Mohd Amin..

Absolutely.. my research is studying on wax deposition problem in crude oil using EVA as a PPD. Instead of doing experimental, I am also running simulation using material studio. I need the MW,EVA structure and density information in order to proceed for the simulation. I have been told MUPA has the GPC equipment. so I think I will send my EVA sample there. We know that EVA contain of VA and ethene ...The most important thing is I need to know the repeatation of x and y value in that EVA.So that I have an idea to draw full polymer structure.

Thank you

Norida

A polymer doesn't have an exact formula. So for your simulation, probably MW from GPC test is enough. and for your information polymers have a molecular weight distribution and MW from GPC is a average molecular weight for a polymer. You can calculate the repeatation of x and y value in that EVA from the fact that polymer content is 25%VA and 75% of ethylene.

Assalamualaikum Norida

Interesting ....For your information, our team also work on EVA as pour point depressant. We working on developing the material but we lack of application test since we new in this field.

Do you have any pour point tester and what is the lowest temperature?

Dear Dr MAjid Mehraban: Thanks for your reply..Really appreciate it. For Example if I got the EVA MW around 300g/mol.For EVA it content of 25% of VA and the rest is ethylene. Mean that the x and y value can be calculate as below

x=(75/100)*300

y=(25/100) *300

Am I right?. so that from the x and y calculated value I directly can find the full formular molecule for EVA...

Tq

Dr Mohd Amin:Waalaikumuslam

Great to hear someone working same as my field. You will applied the PPD crude problem too?.hmm...We do have an equipment for test the pour pour temp known as cloud point and pour point bath. I am using that equipment to find my crude PP temp. BUT to find the cloud point is difficult for crude oils since the crude is black in color.

Tq

Dear Norida Ridzuan

you must consider molecular weight of EVA and ethylene group in your calculation.

x=0.25*300/MW(EVA group)

y=0.75*300/MW(ethylene group)

polymers usually have MW more than 10,000 g/mol. if the EVA has MW around 300g/mol, it's an oligomer.

"CORRECTION"

you must consider molecular weight of VA and ethylene group in your calculation.

x=0.25*300/MW(VA group)

Salam...

Can we get your email address so we can change idea and discuss further

Tq