The Influence of Dyes on the Thermal Stability of Polyamide Fibers

Fester, Walter

doi:10.1177/004051756403400413

Cited by 7 publications

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Thermo‐oxidative degradation of polyamide 6 and 6,6. Kinetics of the formation and inhibition of UV/VIS‐active chromophores

Karstens¹,

Rossbach

1989

Makromol. Chem.

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The thermal oxidation of polyamide 6 and 6,6 gives rise to azomethine groups (Schiff's bases) as a result of the reaction of aldehyde and ketocarbonyl groups with amino end groups. During the course of degradation, these azomethine groups react with each other in an aldol-type condensation to produce conjugated unsaturated oligoenimine structures that absorb in the UV/VIS range. During aldol condensation, the amino end groups are re-formed, allowing them to react again with the carbonyl groups which are continuously supplied by thermal oxidation (auto-oxidation) to form azomethine groups once more. The concentration and sequence length distribution of the oligoenimine structures can be correlated to the concentration profiles of the amino end groups, carboxyl end groups, and carbonyl groups, in a kinetic model. The concentrations of the individual oligo-enimine species calculated with the aid of the model, are in agreement with the figures found experimentally with UV spectroscopy. Sterically hindered phenols inhibit the formation of carbonyl groups, and thus indirectly counteract the formation of oligoenimine structures (kinetic model for the autoxidation of polymers).

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