Characterization of oligomers in poly(ethylene terephthalate) by matrix-assisted laser desorption/ionization mass spectrometry.

Matrix-assisted laser desorption/ionization mass spectrometry was used for the characterization of extracted and synthesized oligo(ethylene terephthalate)s. Generally, cyclic oligomers [GT]n could be found in technical yarns and tiles, whereas our synthesized model oligomers mainly consisted of linear chains H-[GT]n-G. In addition, some other distributions could be identified as H-[GH]n-OH and H-[GGT]1-[GT]n-7/-G linear oligomers and H-[GGT]1-[GT]n-1 cyclic oligomers, where G is an ethylene glycol unit, GG is a diethylene glycol unit, caused by impurities of ethylene glycol, and T is a terephthalic acid unit. NMR and IR investigations were carried out to verify these results.