Browsing by Author "Zille, Andrea"
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- Curcumin Nanoparticles as a Pigment of Polyamide Textiles: Influence of Conditions in the Exhaust Dyeing and Evaluation of Wastewater ToxicityPublication . Moraes, Katharina S.; Oliveira, Aline de; Ferreira, Bruna T. M.; Bona, Evandro; Carneiro, Jaqueline; Peron, Ana Paula; Fernandes, Marta; Zille, Andrea; Leimann, Fernanda V.; Aguiar, Catia R. Lange de; Silva, Márcia G. da; Ferreira, Alexandre J. S.; Vila, Nívea T.; Gonçalves, Odinei HessThe growing demand for eco-friendly and sustainable solutions in textile dyeing has attracted interest in natural dyes, since the synthetic counterparts may be potentially damaging to the environment and require the use of additives to efficiently bind them to the fibers. Curcumin, a natural dye derived from Curcuma longa L. rhizomes, has attracted attention due to its notable biological activity and vibrant yellow-orange hue; however, its direct application remains limited by challenges related to dye fixation and color fastness. This study aimed to evaluate the use of curcumin nanoparticles in the dyeing of polyamide 6.6, as well as to assess the toxicity level of the effluent generated during the exhaust dyeing process. Colloidally stable nanoparticles with average sizes of 454 and 419 nm were obtained with PVP (polyvinylpyrrolidone) and Poloxamer 407 as the polymeric stabilizer, respectively. A factorial 24-1 experimental design was implemented, showing a reduction in color intensity at higher dyeing temperatures, while acidic conditions enhanced dye uptake, leading to improved color depth. Two formulations were selected for a more detailed characterization. Regarding the wash currently used by the textile field, the scores found demonstrated that color did not change during washing. Excellent ratings were found in the rubbing and perspiration fastness and the ultraviolet protection factor for the textiles dyed with PVP and Poloxamer 407 stabilizers. The wastewater of the dyeing process under selected experimental conditions was evaluated with respect to the phytotoxicity, genotoxicity, and cytotoxicity in in vivo models. Based on the results, the wastewater samples analyzed may be environmentally safe.
- Mechanical and optical properties assessment of an innovative PDMS/beeswax composite for a wide range of applicationsPublication . Ariati, Ronaldo; Souza, Andrews; Souza, Maria S.; Zille, Andrea; Soares, Delfim; Lima, Rui A.; Ribeiro, J.E.Polydimethylsiloxane (PDMS) is an elastomer that has received primary attention from researchers due to its excellent physical, chemical, and thermal properties, together with biocompatibility and high flexibility properties. Another material that has been receiving attention is beeswax because it is a natural raw material, extremely ductile, and biodegradable, with peculiar hydrophobic properties. These materials are applied in hydrophobic coatings, clear films for foods, and films with controllable transparency. However, there is no study with a wide range of mechanical, optical, and wettability tests, and with various proportions of beeswax reported to date. Thus, we report an experimental study of these properties of pure PDMS with the addition of beeswax and manufactured in a multifunctional vacuum chamber. In this study, we report in a tensile test a 37% increase in deformation of a sample containing 1% beeswax (BW1%) when compared to pure PDMS (BW0%). The Shore A hardness test revealed a 27% increase in the BW8% sample compared to BW0%. In the optical test, the samples were subjected to a temperature of 80 ◦C and the BW1% sample increased 30% in transmittance when compared to room temperature making it as transparent as BW0% in the visible region. The thermogravimetric analysis showed thermal stability of the BW8% composite up to a temperature of 200 ◦C. The dynamic mechanical analysis test revealed a 100% increase in the storage modulus of the BW8% composite. Finally, in the wettability test, the composite BW8% presented a contact angle with water of 145◦. As a result of this wide range of tests, it is possible to increase the hydrophobic properties of PDMS with beeswax and the composite has great potential for application in smart devices, food and medicines packaging films, and films with controllable transparency, water-repellent surfaces, and anti-corrosive coatings.