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In this research, Styrene Acrylonitrile (SAN) nanofibers, produced by the electrospinning method, were used in order to improve out-of-plane and impact properties of a conventional carbon fiber/epoxy composite. The prepared SAN nanofibers were directly deposited on the surfaces of conventional carbon fiber fabrics. Vacuum assist resin transfer molding (VARTM) was employed for fabricating carbon/epoxy composite. The morphological study of the electrospun SAN nanofibers indicated the prepared SAN nanofibers were smooth, continuous, and without any formation of beads, with average diameters assessed to be 480 ± 102 nm. Mechanical properties studies of the composites indicated that embedding SAN nanofibers in the hybrid composite (carbon/epoxy composite containing SAN nanofibers) led to 26%, 37%, 27%, and 8% of flexural strength, flexural work to fracture, interlaminar shear strength, and impact absorption energy, respectively compared to acquired results from control composite (without nanofibers). Statistical analysis was furthermore carried out to prove the significant differences of the obtained results. Finally, fractographical analysis by field emission scanning electron microscope (FE-SEM) confirmed that embedding nanofibers in the hybrid composite caused tougher fracture during composite breakage. [ABSTRACT FROM AUTHOR]

A self-healing carbon/epoxy composite was fabricated with the incorporation of healing agent loaded core-shell nanofibers between carbon fiber fabric layers. The healing agents, consisting of two components, a low viscosity epoxy resin and its amine-based curing agent, were encapsulated in Styrene acrylonitrile (SAN) nanofibers via a coaxial electrospinning method. Transmission electron microscope (TEM), Fourier Transform Infrared (FTIR), and thermogravimetric analysis (TGA) results confirmed the successful encapsulation of both epoxy and curing agent in SAN nanofiber shells. TGA and the extraction method confirmed a high encapsulation yield (90% for the epoxy resin and 97% for the curing agent). Mechanical studies of the hybrid composite showed that embedding the fabricated core-shell nanofibers did not lead to a reduction in the mechanical properties of host composite, which was corroborated with statistical analysis. Mechanical evaluations and curing behavior studies both showed that incorporation of the aforementioned nanofibers between carbon layers can imbue the conventional carbon/epoxy composite with a self-healing ability, allowing it to repair itself to restore its mechanical properties for up to three cycles at room temperature in absent of any external driving force. [ABSTRACT FROM AUTHOR]

ABSTRACT Dual components of a self-healing epoxy system comprising a low viscosity epoxy resin, along with its amine based curing agent, were separately encapsulated in a polyacrylonitrile shell via coaxial electrospinning. These nanofiber layers were then incorporated between sheets of carbon fiber fabric during the wet layup process followed by vacuum-assisted resin transfer molding to fabricate self-healing carbon fiber composites. Mechanical analysis of the nanofiber toughened composites demonstrated an 11% improvement in tensile strength, 19% increase in short beam shear strength, 14% greater flexural strength, and a 4% gain in impact energy absorption compared to the control composite without nanofibers. Three point bending tests affirmed the spontaneous, room temperature healing characteristics of the nanofiber containing composites, with a 96% recovery in flexural strength observed 24 h after the initial bending fracture, and a 102% recovery recorded 24 h after the successive bending fracture. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44956. [ABSTRACT FROM AUTHOR]

Electrospun functionalized polyacrylonitrile grafted glycidyl methacrylate (PAN-g-GMA) nanofibers are incorporated between the plies of a conventional carbon fiber/epoxy composite to improve the composite's mechanical performance. Glycidyl methacrylate (GMA) is successfully grafted onto polyacrylonitrile (PAN) polymer powder via a free radical mechanism. Characterization of the electrospun PAN and PAN-g-GMA nanofibers indicates that the grafting of GMA does not significantly alter the tensile properties of the PAN nanofibers but results in an increase in the diameter of nanofibers. Statistical analysis of the mechanical characterization studies on PAN-carbon/epoxy hybrid composites conclusively shows that the composite reinforced with functionalized PAN nanofibers has greater mechanical properties than that of both the neat PAN nanofiber enriched hybrid composite and control composite (without nanofibers). The improved performance is attributed to the grafted glycidyl groups on PAN, leading to stronger interactions between the nanofibers and the epoxy matrix. PAN-g-GMA nanofiber reinforced composite outperforms their neat PAN counterparts in tensile strength, short beam shear strength, flexural strength, and Izod impact energy absorption by 8%, 9%, 6%, and 8%, respectively. Compared to the control composite, the improvements resulting from the PAN-g-GMA nanofiber incorporation are even more pronounced at 28%, 41%, 32%, and 21% in the corresponding tests, respectively. [ABSTRACT FROM AUTHOR]

The onset of coronavirus pandemic has sparked a shortage of facemasks in almost all nations. Without this personal protective equipment, healthcare providers, essential workers, and the general public are exposed to the risk of infection. In light of the aforementioned, it is critical to balance the supply and demand for masks. COVID-19 will also ensure that masks are always considered as an essential commodity in future pandemic preparedness. Moreover, billions of facemasks are produced from petrochemicals derived raw materials, which are non-degradable upon disposal after their single use, thus causing environmental pollution and damage. The sustainable way forward is to utilise raw materials that are side-stream products of local industries to develop facemasks having equal or better efficiency than the conventional ones. In this regard, wheat gluten biopolymer, which is a by-product or co-product of cereal industries, can be electrospun into nanofibre membranes and subsequently carbonised at over 700 °C to form a network structure, which can simultaneously act as the filter media and reinforcement for gluten-based masks. In parallel, the same gluten material can be processed into cohesive thin films using plasticiser and hot press. Additionally, lanosol, a naturally-occurring substance, imparts fire (V-0 rating in vertical burn test), and microbe resistance in gluten plastics. Thus, thin films of flexible gluten with very low amounts of lanosol (<10 wt%) can be bonded together with the carbonised mat and shaped by thermoforming to create the facemasks. The carbon mat acting as the filter can be attached to the masks through adapters that can also be made from injection moulded gluten. The creation of these masks could simultaneously be effective in reducing the transmittance of infectious diseases and pave the way for environmentally benign sustainable products. The possible pathway to develop fully bio-based facemasks. Unlabelled Image • Coronavirus pandemic have made facemasks worldwide healthcare essentials • Shortage of masks exposes medical personnel and the public to the risk of infection • Utilisation of sustainable raw materials to develop bio-based masks is needed • Electrospun and compression moulded gluten can be used to develop bio-based masks • Gluten masks can be made flame retardant by adding <10 wt% of lanosol. [ABSTRACT FROM AUTHOR]

This study presents the development of tunable scaffolds with bimodal porosity comprising poly(ε-caprolactone) (PCL) micro-meshes and PCL/gelatin/ε-polylysine (ε-PL) fibrous layers. Pure PCL scaffolds were prepared using the fused deposition modeling technique featuring grid geometry and interconnected micro-pores, followed by electrospinning to produce PCL/gelatin/ε-PL nanofibrous layers. Field emission scanning electron microscopy was employed to investigate the morphological features of the scaffolds, while the physicomechanical properties were studied using tensile and contact angle tests. Antibacterial performance and skin cell toxicity of the scaffolds were determined by bacterial disc diffusion and cell viability assays, respectively. Morphological analysis showed the presence of micro-to nano-sized pores in the developed scaffolds. The mechanical test results revealed that the prepared scaffolds exhibited Young's modulus values similar to the human skin with higher strain. The nanocomposite scaffolds were cytocompatible and effectively eradicated common bacteria associated with cutaneous wounds. In light of the aforementioned results along with facile fabrication, the tunable PCL/gelatin/ε-PL porous scaffolds hold great promise for applications in skin wound repair. [Display omitted] • Scalable bimodal porous wound scaffold was developed using 3D printing and electrospinning. • Direction-independent mechanical performance for aligned electrospun nanofibers was achieved. • Highly efficient antibacterial performance along with cytocompatibility was obtained. [ABSTRACT FROM AUTHOR]