Dynamic Diffusion of Disperse Dye in a Polyethylene Terephthalate Film from an Infrared Spectroscopic Perspective

Abstract

The diffusion behavior of a typical disperse dye, disperse red 9 (DR 9), in the polyethylene terephthalate (PET) film at different temperatures was investigated by attenuated total reflection–Fourier transform infrared spectroscopy and 2D correlation spectroscopy (2Dcos) analyses. According to the Fickian diffusion model, the calculated diffusion coefficients of DR 9 in the PET film at different temperatures were observed to increase with temperature, which might be attributed to the increased free volume and thermal motion in the PET matrix and the rapid movement of DR 9 molecules at higher temperatures. In-detail analysis of the diffusion spectra discerned various kinds of molecular interactions, that is, intramolecular hydrogen bonding interactions of DR 9 and dipole–dipole and π–π interactions between DR 9 and PET. Among these, the dipole–dipole interactions between CO groups of DR 9 and PET occurred first and played a vital role during the diffusion process of DR 9, as deduced from the sequence order of group motions in 2Dcos analysis.

The roles of polymer relaxation phenomena, aqueous dye solubility and the physical properties of water in the mechanism of adsorption of a disperse dye on poly(ethylene terephthalate) fibres: Part 1 polymer relaxation phenomena

“…In this context, it is widely held that elevated dyeing temperatures must be employed in HT dyeing processes because of the very low diffusional behaviour of the dyes within the structurally recalcitrant PET polymer. Evidence to support this generally held view is provided by the findings 4‐10 that the increase in disperse dye diffusion within PET substrates, as expressed in terms of the diffusivity of the dye molecules, that accompanies an increase in dyeing temperature, is related to the temperature‐dependent relaxation processes that occur within the substrate, as expressed in terms of polymer chain segmental mobility and available free volume, in which fibre glass transition assumes a pivotal role.…”

Facet Engineering in Constructing Lewis Acid-Base Pairs for CO 2 Cycloaddition to High Value-Added Carbonates

“…To further study the crucial role of Lewis acidbase pairs in the ring-opening of PO and the CO 2 cycloaddition reaction, in-situ diffuse reflectance infrared Fouriertransform spectroscopy (DRIFT) was performed to study the reaction intermediates by observing bonding alterations in the catalytic reaction. As shown in Figure 4(a), after 30 min treatment with PO under a carbon dioxide atmosphere at 423 K, five new peaks at 670, 1090, 1255, 1410, 1510, and 1680 cm -1 appeared, corresponding to the vibration of C-Br, C-O, C-O-C, carbonate, and C = O, respectively [30][31][32][33][34]. Of note, the formation of C-Br demonstrated that Br atoms acted as a Lewis base sites to attack the carbon atoms in the epoxide, which played a key role in the ring-opening of the epoxide.…”

The roles of elevated temperature and carriers in the dyeing of polyester fibres using disperse dyes: Part 2. Analysis of conventional models of dye adsorption

“…47 The pronounced temperature dependency of disperse dye diffusivity (Table 5), which is generally observed for all dye/fibre systems 5 can be attributed to both the greater kinetic energy of the dye molecules and their enhanced aqueous solubility, as well as enthalpically favoured disperse dye disaggregation and increased levels of both water-induced PET fibre swelling and fibre plasticisation. However, it is also widely accepted that disperse dye diffusivity within polyester materials is primarily governed by the relaxation times of the structural relaxations taking place within the PET polymer (e.g., 140,142,143,[152][153][154][155][156][157][158][159][160][161][162][163] ); this important facet of the disperse dye/PET fibre system is discussed in Section 4.3.…”