Ammonium Y zeolite applied as a thermochemolysis reagent for identification of polyethers and polyesters

A potential thermochemolysis reagent has been tested for the pyrolysis gas chromatographic identification of polyether, polyester and polyether- or polyester-based thermoplastic polyurethane. The main advantage of ammonium Y zeolite over liquid reagents is that it does not react prior to pyrolysis, and its reactions have no incomplete products. The procedure of the thermochemolysis is as simple as running a pyrolysis-GC/MS analysis sampling a powder mixture of roughly equal mass of polymer and ammonium Y zeolite. The GC/MS chromatograms obtained show that the products of thermochemolysis are specific to the diol and dicarboxylic units of the polymer. It was observed that ethanal or 1,4-dioxane forms from ethylene oxide components of polyethers and polyesters, tetrahydrofuran from butylene oxide units, hexanedinitrile from adipate groups, and benzodinitrile from terephthalate groups.

► Alkanedinitrile is produced from alkanedioic groups of the polymer chain by NH4Y.
► Aromatic dinitrile forms from aromatic dicarboxylic groups of the polymer chain.
► Light alkenal or small cyclic ethers are formed from alkylene oxide chain units.