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Cotton fiber is favored by people because of its good moisture absorption, heat preservation, soft feel, comfortable wearing and other excellent performance. In recent years, due to the destruction of the ozone layer, the intensity of ultraviolet radiation at ground level has increased. Cotton fiber will degrade under long time ultraviolet irradiation, which limits the outdoor application of cotton fiber. In this study, titanium dioxide (TiO2) particles were prepared on the surface of cotton fibers with the help of supercritical carbon dioxide (SCCO2) to improve the UV resistance of cotton fibers. The effects of SCCO2 treatment on the morphology, surface composition, thermal stability, photostability and mechanical properties of TiO2 were studied by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, thermogravimetric analysis, UV-VIS spectroscopy, and single fiber test. The results showed that TiO2 particles were generated on the fiber surface, which reduced the photo-degradation rate of cotton fiber. This is because TiO2 can absorb UV rays and reduce the absorption of UV rays by the cotton fiber itself. The synthesis process of SCCO2 is simple and environmentally friendly, which provides a promising technology for the synthesis of metal nitrogen dioxide on natural plant fibers.

Cotton fibers with ultra-high purity cellulose are ideal raw materials for producing nanocellulose. However, the strong hydrogen bond and high crystallinity of cotton fibers affect the dissociation of cotton fibers to prepare nanocellulose. The structures of two kinds of cotton fibers (CM and XM) in different growth stages from 10 to 50 days post-anthesis (dpa) were studied by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). In the process of cotton fiber growth, the deposition rate of cellulose macromolecules firstly increased and then stabilized. Then, the surface morphology, the chemical composition, and the crystal structure of the nanocellulose prepared from cotton fibers with different growth stages by deep eutectic solvent, a green solvent, were characterized by Transmission Electron Microscope (TEM), scanning electron microscopy (SEM) analysis, XRD, and Thermo Gravimetry (TG). The growth time of cotton fibers affected the properties of prepared nanocellulose, and nanocellulose obtained from cotton fibers at about 30 dpa had less energy consumption, higher yield, and milder reaction conditions.

The bond strength and stability of the intermolecular network structure of cellulose play a decisive role in the tensile strength and rupture resistance of paper. In this work, the surface morphology, the chemical composition, and the crystal structure of nanocellulose prepared from cotton fibers were characterized by scanning electron microscopy (SEM) analysis, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) to prepare cotton fiber nanocellulose by green solvent deep-eutectic solvent pretreatment combined with the ultrasonic method. Nanocellulose of different morphology and structure was used as a papermaking additive to explore its effect on the strength performance of the paper. The results show that the burst resistance index of the paper handsheets could be increased by 6.1% and 9.8%. The burst resistance index improved as the added amount of the NFC was increased.

A novel magnetic bio-adsorbent was synthesized by modifying cotton linter (CL) cellulose with deep eutectic solvents (DESs) and Fe3O4 magnetic nanoparticles. And the adsorption mechanism of Cu2+ by Fe3O4/CL-DESs in aqueous solution was proposed.

To collect permeability data and establish its database of fertilizer nutrients and water vapor through different polymer membranes for the development of polymer-coated fertilizer, the permeabilities of N-, P-, and K-nutrient from saturated aqueous of urea, NaH2PO4 and KCl solution and the permeability of water vapor through the membranes of poly lactic acid (PLA), its blends with polystyrene (PS), and its composites with humic acid (HA) particles were determined experimentally at the temperatures of 288, 298, and 308 K, respectively. The effects of the addition of PS and HA particles, temperature, and coating thickness on the permeability of fertilizer nutrient and water vapor were investigated. It was found that the addition of PS and HA increased the permeability for both the fertilizer nutrients and water vapor. The increase in temperature raised the permeability of N-, P-, and K-nutrient while decrease the permeability of water vapor in the range studied.