In situ growth of Bi-MOF on cotton fabrics via ultrasonic synthesis strategy for recyclable photocatalytic textiles.

Bismuth-based metal-organic framework (Bi-MOF) materials have shown potential for treating organic pollutants. In this work, multifunctional textiles were produced by in situ synthesis of CAU-17 on carboxymethylated cotton fabrics by solvothermal and ultrasonic strategies and employed as recyclable photocatalysts. The compositional and structural features of the dense MOF crystal coatings on cotton fibers were confirmed by scanning electron microscopy, X-ray diffraction, and other characterization approaches. Under optimized conditions, the developed functionalized cotton fabrics achieved a photodegradation efficiency of 98.8% under visible light for RhB in water, as well as good recyclability. The described results have provided the basis and reference for the fabrication of MOF-functionalized textiles.

Advances of polyolefins from fiber to nanofiber: fabrication and recent applications.

Polyolefins are a widely accepted commodity polymer made from olefinic monomer consisting of carbon and hydrogen. This thermoplastic polymeric material is formed through reactive double bonds of olefins by the addition polymerization technique and it possesses a diverse range of unique features for a large variety of applications. Among the various types, polyethylene and polypropylene are the prominent classes of polyolefins that can be crafted and manipulated into diversified products for numerous applications. Research on polyolefins has boomed tremendously in recent times owing to the abundance of raw materials, low cost, lightweight, high chemical resistance, diverse functionalities, and outstanding physical characteristics. Polyolefins have also evidenced their potentiality as a fiber in micro to nanoscale and emerged as a fascinating material for widespread high-performance use. This review aims to provide an elucidation of the breakthroughs in polyolefins, namely as fibers, filaments, and yarns, and their applications in many domains such as medicine, body armor, and load-bearing industries. Moreover, the development of electrospun polyolefin nanofibers employing cutting-edge techniques and their prospective utilization in filtration, biomedical engineering, protective textiles, and lithium-ion batteries has been illustrated meticulously. Besides, this review delineates the challenges associated with the formation of polyolefin nanofiber using different techniques and critically analyzes overcoming the difficulties in forming functional nanofibers for the innovative field of applications.

Effect of cation and anion sizes of additive ionic liquid on the crystal structure of poly(vinylidene fluoride) nanofiber.

We investigated the additive ionic liquid (IL) type dependence on the crystal structure of poly(vinylidene fluoride) (PVDF) nanofibers. As additive ILs, we used imidazolium based ILs with different cation and anion sizes. From differential scanning calorimetry (DSC) measurements, we found that there is a proper amount for the additive IL to promote PVDF crystallization, and the proper amount is influenced by the cation size, not by the anion size. In addition, it was found that IL itself inhibited the crystallization, but IL can promote crystallization under the presence of DMF.

Thermal conductivity of polyurethane sheets containing beryllium oxide nanofibers.

Polyvinyl alcohol/beryllium sulfate/polyethyleneimine (PVA/BeSO4/PEI) precursor nanofibers (NFs) was first fabricated to obtain PVA/BeSO4/PEI electrospun NFs by electrospinning technology, finally manufactured beryllium oxide (BeO) NFs followed by various heat treatment methods. The minimum calcination temperature for pure BeO NFs was 1000 °C, and the minimum specific surface area (5.1 m2 g-1) and pore volumes (0.0128 cm3 g-1) were at 1300 °C. 46.18% Be and 53.82% O was measured in BeO NFs by X-ray photoelectron spectroscopy. BeO NFs were then impregnated with polyurethane (PU) aqueous solution to make PU/BeO NFs heat-dissipating sheet. This heat-dissipating sheet showed superior thermal conductivity (14.4 W m-1 K-1) at 41.4 vol% BeO NFs content. The electrical insulating properties of the heat-dissipating sheet were likewise excellent (1.6 × 1012 Ω â–¡-1). In this study, the author attempted to create a thermally conductive but electrically insulating PU/BeO NFs heat-dissipating sheet that could effectively eliminate generated heat from electric equipment.

Structural analysis and dye removal behavior of amorphous titania embedded poly(vinyl butyral) hybrid fiber.

This study reports on the efficient methylene blue (MB) dye removal properties of a polyvinyl butyral (PVB)-amorphous titania (amTiO2) hybrid fiber (PVB-amTiO2F) made by air-gap spinning in acetone solvent. The successful fabrication of PVB-amTiO2F was confirmed by employing Fourier transform infrared, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and energy dispersive X-ray measurement. Batch experiments were used to examine the cationic MB dye adsorption performance in the dark. The observed data showed that the developed PVB-amTiO2F exhibited moderate adsorption efficiency (68-70%) which is comparable to other amorphous titania-rich adsorbents. The adsorption kinetics was well fitted with a pseudo-second-order model, suggesting that adsorption is mainly led by chemisorption. In addition, the MB degradation properties under visible light were also studied afterwards. A possible adsorption mechanism is discussed. Moreover, the as-fabricated fiber exhibited average to good reusability after 6 cycles. Only cationic MB dye solution was able to demonstrate such properties.

Melt-Electrospun Polyethylene Nanofiber Obtained from Polyethylene/Polyvinyl Butyral Blend Film.

We prepared low-density polyethylene (LDPE) nanofiber, a few hundred nanometers in diameter, using polyvinyl butyral (PVB) and a laser melt-electrospinning (M-ESP) device. We blended PVB with LDPE via an internal melt mixer, removed the PVB after M-ESP by ethanol treatment, and studied the influence of PVB on fiber diameter. A substantial diameter reduction with improved crystallinity of LDPE fiber was observed with increased PVB content in the blend. PVB inclusion also increased the polarity of the LDPE/PVB blend, resulting in better spinnability. The removal of PVB from LDPE/PVB blend fiber caused a massive drop in the LDPE fiber diameter, due to fiber splitting, particularly in PVB-rich samples. Fourier transform infrared (FTIR) spectroscopy of fibers confirmed that the prepared nanofiber was the same as pure LDPE fiber.

A nanocrystalline oxygen-deficient bismuth oxide as an efficient adsorbent for effective visible-light-driven photocatalytic performance toward organic pollutant degradation.

In this work, a simple binary oxygen-deficient Bi2O4-x oxide was prepared, and its crystal structure, optical property, band structure and electronic structure were systematically investigated. Plane-wave-based density functional theory (DFT) calculations were also carried out to determine that Bi2O4-x is a typical indirect-gap semiconductor with the bandgap of 1.1 eV. Bi2O4-x adsorbed ca. 99% of rhodamine B and methyl orange, ca. 95% of methylene blue and ca. 80% of phenol in the dark within initial 30 min. The interaction of the oxygen-deficient structure-induced hydroxyls with pollutant molecules is responsible for the excellent adsorption capacity. Due to its excellent adsorption capacity, Bi2O4-x showed much higher photocatalytic degradation activity toward these pollutants (except for methylene blue) under visible light irradiation than the well-studied Bi2O4, Bi2O3 and P25, which had poor or negligible adsorption capacity toward the pollutants. Methylene blue was degraded by Bi2O4-x with further Pd loading. The photocatalytic mechanism of the oxygen-deficient Bi2O4-x were explored. The scavenging test results showed that direct h+ oxidation contributes to the high photocatalytic activity of the oxygen-deficient Bi2O4-x. This study highlights the potential of developing Bi2O4-x-based materials as a new class with both excellent adsorption capacity and highly efficient photocatalytic activity toward versatile pollutants.