Dear Behrang Izadkhah, since it is a polyester (saturated or unsaturated!), It is formed by C, O, and H. The elemental analysis show the relative percentage of each element, which means you can deduce the appropriate chain structure. NMR also gives details on the structure including the presence or absence of double bonds. My Regards

FTIR may give additional clues, esepcially if spectral library is available. Pyrolysis GC/MS may be of great help, but it requires a good amount of background knowledge to interpret.

Dear Behrang, one other thing you could do is to hydrolise the sample of your polymer and analyse the hydrolyzate by MS. You could tell what is acid and what alcohol, eg. when using different ion channels - if you had basic conditions acid should be deprotonated twice, hence it should give singals in negative ion channel (important: as they would be doubly charged the m/z value will be half of the ion mass and isotopic signals will be separated by 0.5 unit). Diol should show in positive ion channel as some sodium adduct or protonated form (if your analysis wouldn't at basic conditions).

Take into account ionisation method, etc. Also, it might be that diol and diacid are too light and they give signals in the same region as solvent additives, etc. However, analysis of oligoesters (products of partial hydrolysis) also could be of some value. Might be that you would need to play around with type and conditions of MS exepriment to get good results.

Hi;

FTIR spectroscopy combined with NMR-data .

With my best regards

Raman spectroscopy is complementary to IR spectroscopy.

Mass spectroscopy...

Thanks everybody for valuable comments

Good morning sir. Izadkhah, saturated and unsaturated polyesters are industrially synthesized using dozens of chemically different raw materials and not always only alcohols and organic acids; and not only with raw materials of C, H and O. These resins are also chemically difficult to handle. The complete analysis of polyester monomers is a series of chemical operations and the use of instrumental and non-instrumental chemical analyzes. I can advise you to consult the scientific literature in which systematic analyzes are also described, and to choose them according to your laboratory equipment. Through the analyzes in FT-IR and / or NMR it is possible to identify a part of the raw materials with a good reliability; in any case, we resort to saponification or transesterification of the polymer, and then we proceed with the various analytical techniques available to it (in these cases the GC-MS and the LC-MS are extremely useful). Often it is even more interesting to know any additives added to the polyester (stabilizers, antioxidants, inhibitors, etc.); but these are for the most part difficult to analyze (difficult to separate from the resin and for the very small quantities present). Wishes! Dr. Giovanni Lucchetti.