A cost-competitive, flexible and safe thermoelectric polyamide 6,6 (PA66) fabric coated with glycerol-doped PEDOT:PSS (PEDOT:PSS + GLY) for use in large area textiles as a heating element in several applications.
Poly(ethylene terephtalate), PET, can be modified with N,N-dimethylacrylamide to obtain a better incorporation of disperse dye (Disperse Blue 79). Minimal variations in the decomposition at 10% level, melting, and glass transition temperatures, show that the thermal stability of modified PET films does not change when compared to nonmodified PET. The atomic force images show nanopeaks formation on the surface due to the modification. Modified PET films show a decrease in the contact angle and then, an increase in the superficial tension measurements, when compared to the value of 37 Ϯ 1 dynes ⅐ cm Ϫ1 (nonmodified), with values liying in the range of 42-46 Ϯ 0.5 dynes ⅐ cm Ϫ1 . The data obtained by photoacoustic spectroscopy (PAS) for dyed PET films show a dye peak at 580 nm. The data analysis of the peak area show that PET films modified with N,N-dimethylacrylamide for 15 min at 85°C, dyed for 6 h at 85°C with a dye concentration of 0.333 g/L, incorporate three times more dye than the nonmodified films dyed in the same conditions. By the data obtained from PAS, it was possible to calculate the depth profile of dyeing with values around 54 m. Factorial analyses show that the dyeing time was the most important variable. The major amount of incorporated dye was obtained by the following combination of variables: temperature and time of modifier treatment were, respectively, 72.5°C and 15 min; time and temperature of dyeing were, respectively, 90°C and 195 min for a dye concentration of 0.133 g/L.
Summary: Dyeing processes using supercritical fluid present advantages over the conventional dyeing process using aqueous medium. Previous works from our group on polymeric fibers such as N,N‐dimethylacrylamide (DMAAm) modified poly(ethylene terephthalate), PET, showed higher sorption of disperse dyes in supercritical medium. Furthermore, recent studies showed that the association of UV radiation and DMAAm treatment leads to a better incorporation of dyes in modified PET soaked in aqueous medium. In this work, modified and non‐modified PET knitted fabrics (KF) were dyed in supercritical CO2 medium. Azo and anthraquinone dyes were used in order to compare the extent of incorporated dye in PET films and PET KF in supercritical CO2. The dyeing process variables were studied by factorial design and by a response surface methodology (RSM) technique. The anthraquinone dye presented a better incorporation in PET than the azo dye. The UV light exposure and the dyeing times inputs showed positive main effects in the incorporation of dyes in PET films and PET KF. From the RSM data, DMAAm and UV light modified PET KF presented 7.43 mg of incorporated azo dye by g of PET if the optimized dyeing conditions, time: 135 min and pressure: 212 bar would be used. In the respective optimized dyeing conditions for the anthraquinone dye, time 150 min and pressure 229 bar, the incorporated dye would be 22.9 mg of dye by g of PET.
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