Dyeing behaviour and light fastness of poly(ethylene terephthalate) films: A correlation with the morphological structure

Abstract

Dedicated to Professor Dr. Josef Schurz on the occasion of his 60th birthdayIsotropic poly(ethy1ene terephthalate) films, when thermally treated above 18OoC, showed an inversion in dyeing behaviour as well as in light fastness. Similar results were found with anisotropic samples thermally treated above 150°C. The morphological characterization of the films showed the inversion points to occur always a t a crystallinity index of about 0.5, but with larger crystallite dimensions in the anisotropic samples. The phenomenon is interpreted assuming that dye diffusion can be explained by replacing the usual "free volume" model by the "pore" model. Farbeverhalten und Lichtechtheit von Polyethylenterephthalat-Filmen: Korrelation mit der morphologischen StrukturIsotrope Polyethylenterephthalat-Filme zeigten nach Temperung oberhalb 180°C eine Umkehr des Farbeverhaltens und der Lichtechtheit. Ahnliche Ergebnisse wurden mit anisotropen Filmen bei thermischer Behandlung oberhalb 150°C erhalten. Die morphologische Untersuchung der Filme zeigte, daB die Umkehr immer bei einem Kristallinitatsindex von etwa 0,5 auftritt, wobei in den anisotropen Proben jedoch gro5ere Kristallite vorliegen. Die Erscheinung wird mit der Annahme interpretiert, daB die Farbstoffdiffusion durch den Wechsel vom ublichen Freien-Volumen-Model1 zu einem Poren-Model1 bestimmt wird. noeeaenue npu xpatuenuu u ceemocmo6xocmb nomwmunexmepe$mcamrmx nnenox: Ecoppemyuu c mp$onozuuecsoii cmpyxmypoii k l 3 0~p o n a~e nonHaTHaeHTepe$lTanaTHne nneHw I I O K~~~I B~I O T mmepcmo B noseaemm npH HpameHm H B cBeTo-CTO~KOCTH nocne OTmHra BHUe 180 "C. r f o~o 6~1 a e pe3yJIbTaTbI ~H J I H nonyYeHbI npH TepMUYeCKOfi o 6 p a 6 0~~~ IHH-3OTpOnHhIX nJIeAOK BbIlIIe 150°C. B pe3yJlbTaTe MOp$lOnOI'HYeCKHX HCCJIeJ(0BaAHfi YCTaHOBJIeHO, YTO HHBepCHfi Bceraa meeT Memo npH cTenem KPHCTaJInHYHOCTH O K O~O 0,5, npmeM B ~H U~O T~O~H~I X o 6 p a a~a x 06HapyXeHH 6onee Kpynme HpucTaanmn. FIsneaue 06%ficafie~cfi TeM npeanonomeauem, YTO a~$ l $ l y 3~~1 Kpacmem onpege-nfieTcfi nepexoaom OT Moaeaw C B O~O~H O~O o6%ema H n o p m r o i Mogenil.

Thermal cis‐trans isomerization and photofading of some azo dyes in poly(ethylene terephthalate) matrices: A kinetic study

“…When considering PET films under T,, the occurrence of a rotational mechanism can be ruled out, since no gauche-trans isomerization of this polymer has been observed under T,. 6 Thus, the cis-trans thermal isomerization of dye associated with a rotational change of the polymer cannot happen. In PET films only translational mechanisms are likely involved.…”