Toward sustainable composites: Graphene‐modified jute fiber composites with bio‐based epoxy resin

Sustainable natural fiber reinforced composites have attracted significant interest due to the growing environmental concerns with conventional synthetic fiber as well as petroleum-based resins. One promising approach to reducing the large carbon footprint of petroleum-based resins is the use of bio-based thermoset resins. However, current fiber-reinforced bio-based epoxy composites exhibit relatively lower mechanical properties such as tensile, flexural strength, and modulus, which limits their wider application. Here the fabrication of high-performance composites using jute fibers is reported, modified with graphene nanoplates (GNP) and graphene oxide (GO), and reinforced with bio-based epoxy resin. It is demonstrated that physical and chemical treatments of jute fibers significantly improve their fiber volume fraction (Vf) and matrix adhesion, leading to enhanced mechanical properties of the resulting Jute/Bio-epoxy (J/BE) composites. Furthermore, the incorporation of GNP and GO further increases the tensile and flexural strength of the J/BE composites. The study reveals the potential of graphene-based jute fiber-reinforced composites with bio-based epoxy resin as a sustainable and high-performance material for a wide range of applications. This work contributes to the development of sustainable composites that have the potential to reduce the negative environmental impact of conventional materials while also offering improved mechanical properties

All Inkjet-Printed Graphene-Silver Composite Ink on Textiles for Highly Conductive Wearable Electronics Applications

© 2019, The Author(s). Inkjet-printed wearable electronic textiles (e-textiles) are considered to be very promising due to excellent processing and environmental benefits offered by digital fabrication technique. Inkjet-printing of conductive metallic inks such as silver (Ag) nanoparticles (NPs) are well-established and that of graphene-based inks is of great interest due to multi-functional properties of graphene. However, poor ink stability at higher graphene concentration and the cost associated with the higher Ag loading in metal inks have limited their wider use. Moreover, graphene-based e-textiles reported so far are mainly based on graphene derivatives such as graphene oxide (GO) or reduced graphene oxide (rGO), which suffers from poor electrical conductivity. Here we report inkjet printing of highly conductive and cost-effective graphene-Ag composite ink for wearable e-textiles applications. The composite inks were formulated, characterised and inkjet-printed onto PEL paper first and then sintered at 150 °C for 1 hr. The sheet resistance of the printed patterns is found to be in the range of ~0.08–4.74 Ω/sq depending on the number of print layers and the graphene-Ag ratio in the formulation. The optimised composite ink was then successfully printed onto surface pre-treated (by inkjet printing) cotton fabrics in order to produce all-inkjet-printed highly conductive and cost-effective electronic textiles

Контролируемые прочностные показатели для различных видов мебели

Методические указания по курсам «Расчет конструкций изделий из древесины и испытания мебели», «Технология изделий из древесины» для выполнения практических и лабораторных работ обучающимися по направлениям 35.03.02, 35.04.02 «Технология лесозаготовительных и деревоперерабатывающих производств», профиль «Технология деревообработки

Smart electronic textile‐based wearable supercapacitors

Abstract: Electronic textiles (e‐textiles) have drawn significant attention from the scientific and engineering community as lightweight and comfortable next‐generation wearable devices due to their ability to interface with the human body, and continuously monitor, collect, and communicate various physiological parameters. However, one of the major challenges for the commercialization and further growth of e‐textiles is the lack of compatible power supply units. Thin and flexible supercapacitors (SCs), among various energy storage systems, are gaining consideration due to their salient features including excellent lifetime, lightweight, and high‐power density. Textile‐based SCs are thus an exciting energy storage solution to power smart gadgets integrated into clothing. Here, materials, fabrications, and characterization strategies for textile‐based SCs are reviewed. The recent progress of textile‐based SCs is then summarized in terms of their electrochemical performances, followed by the discussion on key parameters for their wearable electronics applications, including washability, flexibility, and scalability. Finally, the perspectives on their research and technological prospects to facilitate an essential step towards moving from laboratory‐based flexible and wearable SCs to industrial‐scale mass production are presented

Mechanical and thermal properties of Graphene nanoplatelets-reinforced recycled polycarbonate composites

Nanocomposites have received significant interest in recent years, as they offer improved properties compared to conventional materials for various applications. Among many available nanofillers, graphene nanoplatelets (GNP) have shown promising results for polymer-based nanocomposite applications. This paper investigates the mechanical and thermal properties of GNP-reinforced virgin and recycled polycarbonate (PC) nanocomposites blended via a twin-screw extruder. Effects of various key processing parameters such as filler concentration, processing speed, barrel/die set temperature, and PC type (virgin and recycled) on the reinforced composites were examined. Mechanical properties were characterised by tensile testing, while thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to characterise the thermal properties. The results show that the processing speed and barrel/die set temperature have a slight influence, while the filler concentration significantly affects the properties of PC/GNPs composites. The Young's modulus and yield strength were enhanced with increasing GNP loading, where the maximum enhancement of Young's modulus was obtained as ∼33% for virgin-PC/GNP and ∼39.5% for recycled-PC/GNP composites at 10 wt.-% GNP loading. However, the failure strain was reduced with the increased GNP loading for both virgin and recycled PC/GNP composites. Embedding GNP into the PC matrix only slightly influenced the thermal stability and glassy transition temperature (Tg). The highest thermal stability for virgin PC/GNP composites was observed with 1 wt.-% (2.74% increase with respect to virgin PC), while for recycled PC/GNP, it was observed with 10 wt.-% (2.42% increase with respect to recycled PC) GNP loading. Under the same GNP loading, recycled PC-based composites showed lower thermal stability than virgin PC-based composites. The Tg evaluated from DSC showed a rise under 1 wt.-% GNP for virgin PC/GNP and decrease afterwards with higher filler loading, while an irregular variation for recycled PC/GNP was observed

Engineering Graphene Flakes for Wearable Textile Sensors via Highly Scalable and Ultrafast Yarn Dyeing Technique

© 2019 American Chemical Society. Multifunctional wearable e-textiles have been a focus of much attention due to their great potential for healthcare, sportswear, fitness, space, and military applications. Among them, electroconductive textile yarn shows great promise for use as next-generation flexible sensors without compromising the properties and comfort of usual textiles. However, the current manufacturing process of metal-based electroconductive textile yarn is expensive, unscalable, and environmentally unfriendly. Here we report a highly scalable and ultrafast production of graphene-based flexible, washable, and bendable wearable textile sensors. We engineer graphene flakes and their dispersions in order to select the best formulation for wearable textile application. We then use a high-speed yarn dyeing technique to dye (coat) textile yarn with graphene-based inks. Such graphene-based yarns are then integrated into a knitted structure as a flexible sensor and could send data wirelessly to a device via a self-powered RFID or a low-powered Bluetooth. The graphene textile sensor thus produced shows excellent temperature sensitivity, very good washability, and extremely high flexibility. Such a process could potentially be scaled up in a high-speed industrial setup to produce tonnes (∼1000 kg/h) of electroconductive textile yarns for next-generation wearable electronics applications

Scalable Production of Graphene-Based Wearable E-Textiles

© 2017 American Chemical Society. Graphene-based wearable e-textiles are considered to be promising due to their advantages over traditional metal-based technology. However, the manufacturing process is complex and currently not suitable for industrial scale application. Here we report a simple, scalable, and cost-effective method of producing graphene-based wearable e-textiles through the chemical reduction of graphene oxide (GO) to make stable reduced graphene oxide (rGO) dispersion which can then be applied to the textile fabric using a simple pad-dry technique. This application method allows the potential manufacture of conductive graphene e-textiles at commercial production rates of ∼150 m/min. The graphene e-textile materials produced are durable and washable with acceptable softness/hand feel. The rGO coating enhanced the tensile strength of cotton fabric and also the flexibility due to the increase in strain% at maximum load. We demonstrate the potential application of these graphene e-textiles for wearable electronics with activity monitoring sensor. This could potentially lead to a multifunctional single graphene e-textile garment that can act both as sensors and flexible heating elements powered by the energy stored in graphene textile supercapacitors

The effect of surface treatments and graphene-based modifications on mechanical properties of natural jute fiber composites: A review

Natural fiber reinforced composites (FRC) are of great interests, because of their biodegradability, recyclability, and environmental benefits over synthetic FRC. Natural jute FRC could provide an environmentally sustainable, light weight, and cost-effective alternative to synthetic FRC. However, the application of natural jute FRC is limited because of their poor mechanical and interfacial properties. Graphene and its derivatives could potentially be applied to modify jute fiber surface for manufacturing natural FRC with excellent mechanical properties, and lower environmental impacts. Here, we review the physical and chemical treatments, and graphene-based modifications of jute fibers, and their effect on mechanical properties of jute FRC. We introduce jute fiber structure, chemical compositions, and their potential applications first. We then provide an overview of various surface treatments used to improve mechanical properties of jute FRC. We discuss and compare various graphene derivative-based surface modifications of jute fibers, and their impact on the performance of FRC. Finally, we provide our future perspective on graphene-based jute fibers research to enable next generation strong and sustainable FRC for high performance engineering applications without conferring environmental problems