Preparation of Nanofiber Bundles via Electrospinning Immiscible Polymer Blend for Oil/Water Separation and Air Filtration.

Nanofiber bundles with specific areas bring a new opportunity for selective adsorption and oil/water or air separation. In this work, nanofiber bundles were prepared by the electrospinning of immiscible polystyrene (PS)/N-trifluoroacetylated polyamide 6 (PA6-TFAA) blends via the introduction of carbon nanotubes (CNTs) or a copolymer of styrene and 3-isopropenyl-α, α'-dimethylbenzene isocyanate (TMI), which was denoted as PS-co-TMI. Herein, CNT was used to increase the conductivity of the precursor for enhancing the stretch of PS droplets under the same electric field, and PS-co-TMI was used as a reactive compatibilizer to improve the compatibility of a PS/PA6-TFAA blend system for promoting the deformation. Those obtained nanofiber bundle membranes showed an increase in tensile strength and high hydrophobicity with a water contact angle of about 145.0 ± 0.5°. Owing to the special structure, the membranes also possessed a high oil adsorption capacity of 31.0 to 61.3 g/g for different oils. Moreover, it exhibits a high potential for gravity-driven oil/water separation. For example, those membranes had above 99% separation efficiency for silicon oil/water and paraffin wax/water. Furthermore, the air filtration efficiency of nanofiber bundle membranes could reach above 96%, which might be two to six times higher than the filtration efficiency of neat PS membranes.

Synthesis of carboxymethyl chitosan-functionalized graphene nanomaterial for anticorrosive reinforcement of waterborne epoxy coating.

In this study, a carboxymethyl chitosan functionalized graphene (CMCS-rGO) nanomaterial was successfully synthesized in aqueous solution by non-covalent functionalization method. Fourier transform infrared, Raman, ultraviolet visible spectroscopy and thermogravimetric analysis confirmed that carboxymethyl chitosan had been successfully anchored on the surface of graphene. In addition, the CMCS-rGO was used as an anticorrosive nanofiller to be added to waterborne epoxy (EP) coatings to protect steel substrates. The corrosion protection behavior of all coatings was tested by electrochemical workstation, and the results proved that the incorporation of well-dispersed CMCS-rGO nanomaterials could significantly improve the anti-corrosion performance of waterborne epoxy coatings. Furthermore, even after 180 days of immersion, the impedance modulus value of the 0.2 % CMCS-rGO/EP at |Z|f =0.01 Hz was still approximately 2 orders of magnitude higher than that of the EP.

Fabrication of superhydrophobic cotton fabric with fluorinated TiO2 sol by a green and one-step sol-gel process.

The purpose of this paper is to propose a facile, green and low-cost approach of the preparation of superhydrophobic cotton textiles, which can be fabricated with fluorinated TiO2 sols via a sol-gel method. The coating was prepared with TiO2 sols catalyzed with acetic acid, then modified by poly(Hexafluorobutyl methacrylate) (PHFBMA) which was synthesized by free radical polymerization. The wettability, surface morphology and chemical composition of pristine and modified cotton fabrics were investigated. The modified fabric presents a high contact angle reached up to 152.5°. The successful incorporation of fluorinated TiO2 nanoparticles into cotton fabric was verified by the above measurements results. Additionally, the chemical stability of the coated fabric has been tested by immersing in different pH solutions and organic solvents, demonstrating the outstanding water repellency of the fabric. Furthermore, the treated cotton fabric shows excellent self-cleaning properties, which makes it an ideal material for large-scaled industrial applications in various conditions.