monomer residues in polymer

[michelle.zhang]

Dears,
Any one can supply some information or reference amterials about monomer residues analysis in Polymer?
Thank you.
Michelle

[james little]

We have done a lot of polymer residue analyses over the years. A lot of them in support of FDA petitions. In those, I think there are specified parameters. But generally they dissolve in a mixture of ethanol/water and put in a closed container that will take the pressure generated. These are tests to simulate food-simulating solvents.

We also put in soxhlet extractors with ether or some other solvent that will swell the polymer, but not dissolve it and let it run for several hours.

Another approach is to dissolve the polymer in a solvent such as methylene chloride and then precipitate out the polymer with some alcohol solvent. This leaves the oligomers in solution.

The oligomers in the resulting samples are usually analyzed for concentration by UV/VIS calculating the amount on a reference monomer.

Or we often do LC/MS/diode array (reversed phase with post-column addition of 25 mmolar ammonium acetate in methanol to enhance ionization) in electrospray mode using the UV response to quantify components (use a response based on monomer corrected for the difference in MW of non-UV absorbing parts of the molecule). The mass spec data (low cone voltage pos ion and neg ion for MW information and higher cone voltage in positive and negative to get substructural information).

Another useful technique is proton and C13 NMR which we also use to quantify the mixture.

Good luck.

[Bill Tindall]

And I might add that there is head space analysis for volatile monomers, and the ever popular dissolve it and run down size separation column to separate monomers from polymer.

[himikavarma]

Hi. We have been carrying out monomer residues (particulary styrene monomer & vinyl chloride monomer in polymers, by GC-HS/PID and GC-HS/FID. LoQ is upto 0.01ppm. Reference materials for same are available from Accustandard (under VOCs), USA or Supelco, Germany.
Regards
Himika

[JesseG]

We test for residual monomer by GC with a FID detector. Pretty simple analysis by dissolving the polymer in solvent then injecing.

[bijelic]

we also did analysis of monomers residues but with GC/MS. shortly, we dissolve polystirene in toluene and precipated with the MeOH and we injected a part of supernatant, results were just fine. we also downloaded some methods from the net but they were, let's say a bit unusual, since they included injection of polymer itself, i am not quite sure what would something like that do to your column.

good luck