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Keywords = self-colored polyurethane

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18 pages, 7383 KB  
Article
Color and Chemical Stability of 3D-Printed and Thermoformed Polyurethane-Based Aligners
by Luka Šimunović, Sara Čekalović Agović, Antun Jakob Marić, Ivana Bačić, Eva Klarić, Flavio Uribe and Senka Meštrović
Polymers 2024, 16(8), 1067; https://doi.org/10.3390/polym16081067 - 11 Apr 2024
Cited by 33 | Viewed by 6801
Abstract
The significant rise in the use of clear aligners for orthodontic treatment is attributed to their aesthetic appeal, enhancing patient appearance and self-confidence. The aim of this study is to evaluate the aligners’ response to common staining agents (coffee, black tea, Coca-Cola, and [...] Read more.
The significant rise in the use of clear aligners for orthodontic treatment is attributed to their aesthetic appeal, enhancing patient appearance and self-confidence. The aim of this study is to evaluate the aligners’ response to common staining agents (coffee, black tea, Coca-Cola, and Red Bull) in color and chemical stability. Polyurethane-based thermoformed and 3D-printed aligners from four brands were exposed to common beverages to assess color change using a VITA Easyshade compact colorimeter after 24 h, 48 h, 72 h, and 7 days, as well as chemical stability using ATR-FTIR spectroscopy. The brand, beverage, and manufacturing method significantly influence color stability. ATR-FTIR analysis revealed compositional differences, with variations in response to beverage exposure affecting the integrity of polymer bonds. Color change analysis showed coffee as the most potent staining agent, particularly affecting Tera Harz TC85 aligners, while ClearCorrect aligners exhibited the least susceptibility. 3D-printed aligners showed a greater color change compared to thermoformed ones. Aligners with a PETG outer layer are more resistant to stains and chemical alterations than those made of polyurethane. Additionally, 3D-printed polyurethane aligners stain more than thermoformed ones. Therefore, PETG-layered aligners are a more reliable choice for maintaining the aesthetic integrity of aligners. Full article
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20 pages, 5872 KB  
Article
Design and Performance of Novel Self-Cleaning g-C3N4/PMMA/PUR Membranes
by Ladislav Svoboda, Nadia Licciardello, Richard Dvorský, Jiří Bednář, Jiří Henych and Gianaurelio Cuniberti
Polymers 2020, 12(4), 850; https://doi.org/10.3390/polym12040850 - 7 Apr 2020
Cited by 23 | Viewed by 5602
Abstract
In the majority of photocatalytic applications, the photocatalyst is dispersed as a suspension of nanoparticles. The suspension provides a higher surface for the photocatalytic reaction in respect to immobilized photocatalysts. However, this implies that recovery of the particles by filtration or centrifugation is [...] Read more.
In the majority of photocatalytic applications, the photocatalyst is dispersed as a suspension of nanoparticles. The suspension provides a higher surface for the photocatalytic reaction in respect to immobilized photocatalysts. However, this implies that recovery of the particles by filtration or centrifugation is needed to collect and regenerate the photocatalyst. This complicates the regeneration process and, at the same time, leads to material loss and potential toxicity. In this work, a new nanofibrous membrane, g-C3N4/PMMA/PUR, was prepared by the fixation of exfoliated g-C3N4 to polyurethane nanofibers using thin layers of poly(methyl methacrylate) (PMMA). The optimal amount of PMMA was determined by measuring the adsorption and photocatalytic properties of g-C3N4/PMMA/PUR membranes (with a different PMMA content) in an aqueous solution of methylene blue. It was found that the prepared membranes were able to effectively adsorb and decompose methylene blue. On top of that, the membranes evinced a self-cleaning behavior, showing no coloration on their surfaces after contact with methylene blue, unlike in the case of unmodified fabric. After further treatment with H2O2, no decrease in photocatalytic activity was observed, indicating that the prepared membrane can also be easily regenerated. This study promises possibilities for the production of photocatalytic membranes and fabrics for both chemical and biological contaminant control. Full article
(This article belongs to the Section Polymer Applications)
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13 pages, 1630 KB  
Article
Preparation and Characterization of Self-Colored Waterborne Polyurethane and Its Application in Eco-Friendly Manufacturing of Microfiber Synthetic Leather Base
by Yulu Wang and Liqiang Jin
Polymers 2018, 10(3), 289; https://doi.org/10.3390/polym10030289 - 8 Mar 2018
Cited by 30 | Viewed by 6754
Abstract
A novel self-colored waterborne polyurethane (SCPU) was synthesized and used in the preparation of a microfiber synthetic leather (MS-Leather) base in order to reduce the pollution caused by N,N-dimethylformamide (DMF) and dyes. The SCPU was prepared using the reaction of [...] Read more.
A novel self-colored waterborne polyurethane (SCPU) was synthesized and used in the preparation of a microfiber synthetic leather (MS-Leather) base in order to reduce the pollution caused by N,N-dimethylformamide (DMF) and dyes. The SCPU was prepared using the reaction of a reactive brilliant red K-2G with a waterborne polyurethane which was then extended via a first generation of hyperbranched poly(amine-ester). With the introduction of the dye, new absorption peaks at 1118 cm−1 [S=O], 1413 cm−1 [N=N], and 1635 cm−1 [C=N] appeared in the Fourier transform infrared (FTIR) spectrum of SCPU, and SCPU mean particle size increased to 162 nm. The X-ray diffraction (XRD) peak intensity of SCPU at 19.27° was 1310 cts. The thermal stability of SCPU at 200–280 °C was inferior to that of the control sample; however, it improved at temperatures above 360 °C. Finally, a free-dyeing MS-Leather base prepared by using SCPU without DMF was manufactured. It was found that the dyes were distributed mainly in the polyurethane matrix rather than in the microfibers. Moreover, the color changes of the base before and after being washed in both a water and a soap solution were 0.93 and 4.21, respectively. This indicated that the base’s washing color fastness to water was better than to a soap solution. Full article
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