Fabrication of cellulose fine fiber based membranes embedded with silver nanoparticles via Forcespinning

This study presents the successful development of cellulose fiber based membranes embedded with silver nanoparticles. These fine fiber membranes were developed utilizing the Forcespinning (FS) technique followed by alkaline hydrolysis treatment. The fiber morphology, homogeneity and yield were optimized by varying spinning parameters such as polymer concentration and angular velocity of the spinnerets. The structure, thermal and mechanical properties, and water absorption capability of the developed membranes were investigated. The cellulose acetate (CA) present in the membrane was converted to cellulose in the presence of embedded silver nanoparticles by alkaline hydrolysis. The silver nanoparticles embedded cellulose membrane exhibits outstanding water absorption capacity with fast uptake rate. Its high porosity, three-dimensional network structure with wellinterconnected pores, as well as the intrinsically highly hydrophilic nature of cellulose material greatly favor its potential application as wound dressings. The antimicrobial activity was evaluated by the disk diffusion method. The composite membranes exhibit excellent antimicrobial activity against Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and Gram-positive Staphylococcus aureus, owing to the slow and sustained release of embedded silver nanoparticles

Development of hierarchical structured carbon nanotube-nylon nanofiber mats

A hierarchical nanofiber (NF) structure featuring carbon nanotubes (CNTs) densely attached on the surface of NFs is presented. Nonwoven NF mats made of Nylon 6 (Nylon) were mass produced using the forcespinning® (FS) technology, followed by depositing functionalized CNTs (f-CNTs) on the surface of NFs. Strong interfacial adhesion between CNTs and Nylon NFs was developed by the formation of covalent bonds. The morphology, structure, conductivity, and mechanical properties of the developed CNT-Nylon NFs were analyzed. The hierarchical NFs have a 338% improvement in tensile strength without compromising its strain at break. The shielding effectiveness (SE) of electromagnetic interference (EMI) was recorded to be 30 dB. These promising characteristics endow novel flexible hierarchical NF mats for applications as EMI shielding materials or smart textiles to mention some

Mass production of carbon nanotube-reinforced polyacrylonitrile fine composite fibers

A facile and large-scale production method of polyacrylonitrile (PAN) fibers and carboxyl functionalized carbon nanotube reinforced PAN composite fibers was demonstrated by the use of Forcespinning® technology. The developed polymeric fibers and carbon nanotube-reinforced composite fibers were subsequently carbonized to obtain carbon fiber systems. Analysis of the fiber diameter, homogeneity, alignment of carbon nanotube and bead formation was conducted with scanning electron microscopy. Thermogravimetric analysis, electrical, and mechanical characterization were also conducted. Raman and FTIR analyses of the developed fiber systems indicate interactions between carbon nanotubes and the carbonized PAN fibers through π–π stacking. The carbonized carbon nanotube-reinforced PAN composite fibers possess promising applications in energy storage applications

Fibrous cellulose membrane mass produced via forcespinning® for lithium-ion battery separators

In this study, fibrous cellulose membranes were successfully mass produced by forcespinning® cellulose acetate, followed by alkaline hydrolysis treatment. Its performance as lithium-ion battery separator was evaluated. The cellulose membrane exhibits a randomly-oriented, fully-interconnected and highly porous three-dimensional fibrous network structure with a high porosity of 76 %. The developed membranes show good electrolyte wettability and high electrolyte uptake capability. Differential scanning calorimetry and thermal treatment show a superior thermal stability of the cellulose nonwoven membrane. Compared to commercially available polypropylene based separators, the developed fibrous cellulose membrane displays higher ionic conductivity, lower interfacial resistance and better electrochemical stability. Given its outstanding thermal characteristics and excellent electrochemical performance, this fibrous cellulose membrane has potential to be used as high-performance lithium-ion battery separator. This study provides a novel and feasible pathway for developing promising separators for high-performance lithium ion batteries

The production of carbon nanotube reinforced poly(vinyl) butyral nanofibers by the Forcespinning® method

Poly(vinyl) butyral (PVB) nanofibers (NFs) and carbon nanotube (CNT) reinforced PVB NF composites were developed by using the Forcespinning® technology. PVB was dissolved in a mixture of ethanol and methanol (7:3 wt/wt) at various concentrations, and the solutions were spun at rotational speeds varying between 3,000 and 9,000 rpm. The CNT/PVB solutions were prepared using the same solvent ratio with varying the concentration of CNTs. The results show that the diameter of the PVB fibers increased with increasing rotational speed; however the standard deviation of the fiber diameter distribution decreased. The morphology and thermal properties of the developed fiber systems were studied by DSC, TGA, Raman, and FTIR. The effect of CNT on the mechanical properties of the developed fibers was investigated by carrying out tensile tests at different strain rates. Raman and FTIR analyses indicate a noncovalent π–π stacking interactions and hydrogen bonding between CNT and the PVB NFs. Adding CNT to the PVB NF matrix resulted in improved tensile strength by 150%. POLYM. ENG. SCI., 55:81–87, 2015. © 2014 Society of Plastics Engineer

Novel sulfhydryl functionalized covalent organic frameworks for ultra-trace Hg2+ removal from aqueous solution

Two kinds of novel sulfhydryl functionalized covalent organic frameworks were fabricated as adsorbents for the removal of ultra-trace concentrations of Hg(2+)from water. The two kinds of sulfhydryl functionalized covalent organic frameworks were obtained via a thiol-ene click reaction between the thiol groups of trithiocyanuric acid (TTC) or bismuththiol (BMT) and vinyl groups on the surface of covalent organic frameworks. The material structure was characterized by XRD, SEM, EDS, FT-IR, BET, and TG analysis. Due to their rich sulfur content, both adsorbents (COF-SH-1 and COF-SH-2) exhibited a high level of selective Hg2+ removal from aqueous solution with maximum adsorption capacities of 763.4 mg g(-1) and 526.3 mg g(1,) respectively. Furthermore, in the presence of ultra-low concentrations of Hg2+ both materials exhibited excellent performance, achieving rapid Hg2+ removal at concentrations from 10 mu g L-1 to less than 0.02 ng L-1. Analysis of the adsorption mechanism indicates that the sulfur containing chelating groups exhibit a strong binding capacity for Hg2 +. Results show that the structure determines the performance, with the amount of adsorption sites being related to the adsorption capacity. Therefore, as sulfhydryl functionalized covalent organic frameworks contain an abundance of adsorption sites, these materials can effectively achieve the removal of ultra-low trace Hg2+ concentrations and have promising future application potential for the environmental detection of heavy metals. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals

Simple descriptor derived from symbolic regression accelerating the discovery of new perovskite catalysts

Symbolic regression holds big promise for guiding materials design, yet its application in materials science is still limited. Here the authors use symbolic regression to introduce an activity descriptor predicting new oxide perovskites with improved oxygen evolution activity as corroborated by experimental validation