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Simultaneous diffusion of a disperse dye and a solvent in PET film analyzed by rutherford backscattering spectrometry
Author(s) -
Stinson Roberta M.,
Obendorf S. K.
Publication year - 1996
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19961219)62:12<2121::aid-app14>3.0.co;2-8
Subject(s) - solvent , crystallinity , diffusion , materials science , rutherford backscattering spectrometry , aqueous solution , analytical chemistry (journal) , glass transition , polymer chemistry , disperse dye , polystyrene , dyeing , chemistry , polymer , composite material , chromatography , thin film , organic chemistry , nanotechnology , physics , thermodynamics
Poly(ethylene terephthalate) (PET) is a difficult fiber to dye from an aqueous dyebath due to its high degree of crystallinity and lack of polar groups. One method used to increase the dyeing rate of the fibers is the addition of an organic solvent, called a dye carrier, to the aqueous bath. This study utilized Rutherford backscattering spectrometry and neutron activation analysis to examine both simultaneous diffusion and individual diffusion characteristics of a disperse dye and dye carrier into PET film. The dye exhibited Fickian diffusion above and below glass transition temperature ( T g ) of the PET film both in the presence and absence of solvent. The presence of carrier in the dyebath was found to increase the diffusion coefficient of the dye at each temperature condition; increasing from 10 −14 to 10 −11 cm 2 /s below T g (65°C) and 10 −12 to 10 −10 cm 2 /s above T g (90°C). Bromobenzene exhibited case II diffusion below T g of the film, which indicates that the solvent is swelling the near surface regions of the film. This increase in void volume resulted in an increased dye uptake when films dyed inthe presence of carrier were compared with those dyed without carrier. In fact, the penetration depth of the dye was found to be equivalent to that of the swollen region of the film (∼ 600 nm) after 15 s. Above T g , the bromobenzene exhibited Fickian diffusion. The coupling of the increased thermal motion of the polymer at the higher temperature and the solvent effect increased dye uptake when compared either with dye uptake at the lower temperature or with uptake when no solvent was present. The application of the dye and solvent simultaneously did not affect the diffusion mechanism of either species, leading to the conclusion that there was no competition for specific sites between these two species in the PET film. Similar results were obtained for chlorobenzene when used as the dye carrier. © 1996 John Wiley & Sons, Inc.