PHOTOCHEMICAL CROSS-LINKING OF NYLON-6,6 INDUCED BY 2-SUBSTITUTED ANTHRAQUINONES

The photochemical crosslinking of nylon-6,6 in fibre and film form is successfully carried out for the first time using novel 2-acryloxy and acrylamido substituted anthraquinone initiators without the necessity for the incorporation of a vinyl or acrylic, based crosslinking agent. High degrees of photocrosslinking are observed, as measured by the percentage insolubility in formic acid, depending on the structure of the initiator. The 2-acrylamidoanthraquinone is shown to be the most effective crosslinking initiator, being more effective than the conventional 2-substituted thioxanthione initators. The initiators may be incorporated in the melt by solution casting or by solvent swelling and, from initial spectroscopic studies in solution and film, are shown to undergo photoreduction via hydrogen atom abstraction to give active semiquinone radicals. The latter are implicated in the crosslinking reaction with the acrylic substituted groups in the anthraquinones possibly playing an additional role in enhancing the crosslinking.