Coloration Modeling and Processing of Commodity Plastic Buttons in Supercritical Carbon Dioxide.

We examined the color processing of the commodity plastic buttons made of acrylic, polyester, nylon, and casein with scCO2. The buttons' dyeing color depth (K/S) was measured over a wide range of scCO2 and correlated accurately with the response surface method. Moreover, we measured the solubility of C.I. Disperse Red 22 in scCO2 to formulate a dye-sorption model for the K/S value in the color processing of the plastic buttons. Finally, the dye-sorption model for the K/S value combining the dye solubility in scCO2 with the dye diffusion inside the buttons successfully represented the color processing of the buttons.

Construction of ratiometric hydrogen sulfide probe with two reaction sites and its applications in solution and in live cells.

Hydrogen sulfide (H2S), as the third multifunctional signaling biomolecule, it acts as a neuromodulator in the human brain and is recognized as an important gas transmitter in human physiology. The abnormal concentrations of H2S in human cells can result in several common diseases. Therefore, accurate, fast, and reliable methodologies are required for measuring the in vitro and in vivo concentrations of H2S to further investigate its function. In this study, a novel DR-SO2N3 fluorescent probe containing the fluorophore Disperse Red 277 and a sulfonyl azide group was developed and exploited based on the structural characteristic of Disperse Red 277 that contains the active site easily can be attacked by HS-. Therefore, this probe featured two reaction sites that involved the reduction and Michael addition of H2S and exhibited rapid ratiometric fluorescence changes and high selectivity towards H2S with a 619-fold enhancement factor. Further, the density functional theory (DFT)/time-dependent density functional theory (TDDFT) studies are conducted to understand the photophysical properties of DR-SO2N3 and the final product DRHS-SO2NH2, which makes the proposed mechanism more reasonable. Furthermore, the probe was successfully applied for the ratiometric fluorescence imaging of exogenous H2S in living cells.

Prediction of Acid Red 138 solubility in supercritical CO2 with water co-solvent.

Acid Red 138, as a weak acid azo dye with a long alkyl chain, is widely used for protein fiber dyeing while it cannot dissolve in supercritical carbon dioxide. The objective of this study is to investigate the solubility of Acid Red 138 with water at the temperatures of 353.15, 363.15, 373.15, 393.15 and 413.15 K and over a pressure range of 20 to 26 MPa. The test results revealed that the phase equilibrium of water and Acid Red 138 was affected by the competition between pressure and density of supercritical carbon dioxide. Furthermore, the experimental solubilities were correlated by three types of density-based model. Good agreement with less than 3.36% of average absolute relative deviation between the calculated and the experimental data of water was achieved. In addition, the Chrastil model, Mendez-Santiago-Teja model and Sung-Shim model exhibited excellent correlation results for Acid Red 138 solubilities with the AARD values of 8.58%, 6.06% and 5.19%. Better understanding of the solubility behavior of Acid Red 138 in supercritical carbon dioxide displays potential for developing a microemulsion system for the eco-friendly dyeing of natural fibers.

Thermosensitive Behavior and Super-Antibacterial Properties of Cotton Fabrics Modified with a Sercin-NIPAAm-AgNPs Interpenetrating Polymer Network Hydrogel.

Poly(N-isopropylacrylamide) (PNIPAAm), sericin (SS), and silver nitrate were combined to prepare an interpenetrating network (IPN) hydrogel having dual functions of temperature sensitivity and antibacterial properties. The structure and size of AgNPs in such an IPN hydrogel were characterized by the Fourier Transform Infrared spectrum (FT-IR), X-ray powder diffraction (XRD) and Transmission Electron Microscope (TEM), and the thermal properties of the IPN hydrogel were characterized by Differential Scanning Calorimetry (DSC). Based on XRD patterns, Ag⁺ was successfully reduced to Ag° by SS. It was observed by TEM that the particle size of silver particles was lower than 100 nm. The glass transition temperature (Tg) of IPN hydrogel was better than that of the PNIPAAm/AgNPs hydrogels, and lower critical solution temperature (LCST) values of the IPN hydrogel were obtained by DSC i.e. 31 °C. The thermal stability of the IPN hydrogel was successfully determined by the TGA. This IPN hydrogel was then used to modify the cotton fabrics by the "impregnation" method using glutaraldehyde (GA) as the cross-linking agent. The structures and properties of IPN hydrogel modified cotton fabric were characterized by scanning electron microscopy (SEM), FT-IR, and the thermogravimetry analysis (TGA). The results show that NIPAAm was successfully polymerized into PNIPAAm, and that there were neglected new groups in the hydrogel IPN. The IPN hydrogel was then successfully grafted onto cotton fabrics. SEM observations showed that the IPN hydrogel formed a membrane structure between the fibers, and improved the compactness of the fibers. At the temperature close to LCST (≈31 °C), the entire system was easily able to absorb water molecules. However, the hydrophilicity tended to decrease when the temperature was higher or lower than the LCST. The antibacterial rates of the modified cotton fabric against S. aureus and E. coli were as high as 99%.

Polyester Fabric's Fluorescent Dyeing in Supercritical Carbon Dioxide and its Fluorescence Imaging.

As one of the most important coumarin-like dyes, disperse fluorescent Yellow 82 exhibits exceptionally large two-photon effects. Here, it was firstly introduced into the supercritical CO2 dyeing polyester fabrics in this work. Results of the present work showed that the dyeing parameters such as the dyeing time, pressure and temperature had remarkable influences on the color strength of fabrics. The optimized dyeing condition in supercritical CO2 dyeing has been proposed that the dyeing time was 60 min; the pressure was 25 MPa and the temperature was 120 °C. As a result, acceptable products were obtained with the wash and rub fastness rating at 5 or 4-5. The polyester fabrics dyed with fluorescent dyes can be satisfied for the requirement of manufacturing warning clothing. Importantly, the confocal microscopy imaging technology was successfully introduced into textile fields to observe the distribution and fluorescence intensity of disperse fluorescent Yellow 82 on polyester fabrics. As far as we know, this is the first report about supercritical CO2 dyeing polyester fabrics based on disperse fluorescent dyes. It will be very helpful for the further design of new fluorescent functional dyes suitable for supercritical CO2 dyeing technique.

Incorporation of Rutin in Electrospun Pullulan/PVA Nanofibers for Novel UV-Resistant Properties.

This study aimed to investigate the incorporation of rutin into electrospun pullulan and poly(vinyl alcohol) (PVA) nanofibers to obtain ultraviolet (UV)-resistant properties. The effect of weight ratios between pullulan and PVA, and the addition of rutin on the nanofibers' morphology and diameters were studied and characterized by scanning electron microscopy (SEM). Fourier transform infrared (FTIR) analysis was utilized to investigate the interaction between pullulan and PVA, as well as with rutin. The results showed that the inclusion of PVA results in the increase in the fiber's diameter. The addition of rutin had no obvious effect on the fibers' average diameters when the content of rutin was less than 7.41%. FTIR results indicated that a hydrogen bond formed between pullulan and PVA, also between these polymers and rutin. Moreover, the addition of rutin could enhance the mechanical properties due to its stiff structure and could decrease the transmittance of UVA and UVB to be fewer than 5%; meanwhile, the value of ultraviolet protection factor (UPF) reached more than 40 and 50 when the content of rutin was 4.46% and 5.67%, respectively. Therefore, the electrospun pullulan/PVA/rutin nanofibrous mats showed excellent UV resistance and have potential applications in anti-ultraviolet packaging and dressing materials.