Studies on thermal degradation of aliphatic polyamides by pyrolysis-glass capillary chromatography

A series of aliphatic polyamides samples (five kinds of α-aminocarboxyclic acid-type nylons and seven kinds of diamine-dicarboxyclic acid-type nylons) were pyrolysed in a vertical microfurnace-type pyrolyser at 550°C, and their high-resolution pyrograms were obtained by a glass capillary gas chromatograph directly attached to the pyrolyser. The characteristic peaks on the resulting pyrograms were identified using a mass spectrometer, which was also attached to the gas chromatograph. On the basis of the various characteristic degradation products identified, such as hydrocarbons, mononitriles, lactams, cyclopentanone hydrocarbons containing one amide group and mononitriles containing one amide group, general mechanisms for the degradation of the aliphatic polyamides were formulated.