Cellulosic materials have gained a lot of attention in the last decades because of their abundancy, renewability and excellent physicochemical properties. Meanwhile, research on nanofibers has also been increasing with the aim of producing or modifying materials that can have a wide range of applications, such as tissue engineering, drug delivery, protective clothing and wound dressing. In order to produce these fibers, electrospinning is shown to be a promising and extensively used technique. Electrospun cellulosic fibers maintain the optimal characteristics of cellulose while improving its surface area to volume ratio and mechanical properties, in addition to the possibility of surface tailoring of bulk materials. However, there are several limitations related to the utilization of cellulose and most of its derivatives with the electrospinning technique. Poor solubility in most common solvents and inability to melt are major drawbacks. Thus, this review describes mostly recent research in which cellulose and its derivatives have been the feedstock for fabrication of nanofibers by electrospinning, exploring processing details and potential applications.

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Electrospinning technology was used to produced polyvinylpyrrolidone (PVP)-copper salt composites with structural differences, and their virucidal activity against coronavirus was investigated. The solutions were prepared with 20, 13.3, 10, and 6.6% w/v PVP containing 3, 1.0, 0.6, and 0.2% w/v Cu (II), respectively. The rheological properties and electrical conductivity contributing to the formation of the morphologies of the composite materials were observed by scanning electron microscopy (SEM). SEM images revealed the formation of electrospun PVP-copper salt ultrafine composite fibers (0.80 ± 0.35 µm) and electrosprayed PVP-copper salt composite microparticles (1.50 ± 0.70 µm). Energy-dispersive X-ray spectroscopy (EDS) evidenced the incorporation of copper into the produced composite materials. IR spectra confirmed the chemical composition and showed an interaction of Cu (II) ions with oxygen in the PVP resonant ring. Virucidal composite fibers inactivated 99.999% of coronavirus within 5 min of contact time, with moderate cytotoxicity to L929 cells, whereas the virucidal composite microparticles presented with a virucidal efficiency of 99.999% within 1440 min of exposure, with low cytotoxicity to L929 cells (mouse fibroblast). This produced virucidal composite materials have the potential to be applied in respirators, personal protective equipment, self-cleaning surfaces, and to fabric coat personal protective equipment against SARS-CoV-2, viral outbreaks, or pandemics.

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In this work, an investigation was carried out on the effect of ultraviolet light on different films. Polystyrene (PS), poly (caprolactone) (PCL), and blended films of PS/PCL were produced. Ethyl acetate (AE) was used as a solvent, and PS and PCL solutions were prepared by dissolving 250 mg in 2.5mL of AE under mechanical stirring at room temperature. The blended solutions of PS/PCL (PS:PCL) were prepared with different mass proportions, such as 90:10, 80:20, 70:30, and 60:40 into 2.5 mL of EA. The solutions were dripped with 500 µL on a glass substrate, and the films were produced with mechanical rotation of N=2000 RPM for 15 seconds using a Spin coater. The films were submitted to ultraviolet light for t=60 minutes and morphologically analyzed by optical microscopy, chemically by IR spectroscopy, and superficially by contact angle and wettability; this last analysis also investigated the effect of ultraviolet light at t=0, t=30, and t=60 minutes. The exposure of ultraviolet light on the films affected its morphologies. IR spectra showed that the photodegradation increased for larger PCL amounts into the blend. The contact angle measurements showed that after exposure to ultraviolet light, the hydrophobicity of the films increased. Therefore, the presence of PCL in the polymer mixture promoted the photodegradation of the PS/PCL films, making it attractive for developing new packaging.

In this work, an investigation was carried out on the effect of ultraviolet light on different films. Polystyrene (PS), poly (caprolactone) (PCL), and blended films of PS/PCL were produced. Ethyl acetate (AE) was used as a solvent, and PS and PCL solutions were prepared by dissolving 250 mg in 2.5mL of AE under mechanical stirring at room temperature. The blended solutions of PS/PCL (PS:PCL) were prepared with different mass proportions, such as 90:10, 80:20, 70:30, and 60:40 into 2.5 mL of EA. The solutions were dripped with 500 µL on a glass substrate, and the films were produced with mechanical rotation of N=2000 RPM for 15 seconds using a Spin coater. The films were submitted to ultraviolet light for t=60 minutes and morphologically analyzed by optical microscopy, chemically by IR spectroscopy, and superficially by contact angle and wettability; this last analysis also investigated the effect of ultraviolet light at t=0, t=30, and t=60 minutes. The exposure of ultraviolet light on the films affected its morphologies. IR spectra showed that the photodegradation increased for larger PCL amounts into the blend. The contact angle measurements showed that after exposure to ultraviolet light, the hydrophobicity of the films increased. Therefore, the presence of PCL in the polymer mixture promoted the photodegradation of the PS/PCL films, making it attractive for developing new packaging.