CHARACTERIZATION OF END-GROUPS IN NYLON-6 BY MALDI-TOF MASS-SPECTROMETRY

Four samples of Ny6, each terminated by different end groups, i.e., di amino terminated, monoamino terminated (monocapped), dicarboxyl termin ated, and amino-carboxyl terminated, were synthesized and analyzed by MALDI-TOF Mass Spectrometry, in order to accurately characterize their structure by direct identification of mass resolved chains. A self-ca librating method for the MALDI-TOF mass spectra of polymeric samples w as used in order to distinguish the end groups existing in the four sa mples of Ny6. The MALDI-TOF spectra showed the presence of protonated, sodiated, and potassiated ions that were assigned to Ny6 chains conta ining the expecteted end groups. Furthermore, the MALDI-TOF spectra ma de possible the simultaneous detection of the cyclic oligomers of Ny6 present in these samples, thus achieving the full structural character ization of the molecular species present in these polyamides. (C) 1996 John Wiley & Sons, Inc.