The drive toward sustainable practices and principles across the supply chain has led to an upsurge in renewable materials. Epoxy resins are used in a wide range of applications in various fields, ...such as coatings, adhesives, castings, modeling compounds, impregnation materials, high-performance composites, insulating materials, and encapsulating and packaging materials for electronic devices. In order to achieve the desired properties, uncured epoxy resins must be converted to hard, infusible, thermoset networks in the presence of a variety of curing agents, also known as hardeners. This paper reviews recent advances in the development of curing agents from renewable materials. Attention is given to modified plant oils, biobased acids and anhydrides, amines and their derivatives, biobased phenols, rosin acids, and terpenes and lignin as biobased curing agents for primarily epoxy resin or biobased epoxy resin systems.
Various 3D printing methods like inkjet printing, direct ink writing, and fused deposition modelling were reported in this review. Firstly, the work covered various 3D printed carbon-based LIB ...electrodes and goes on to cover the 3D printed metal oxides-based LIB electrodes, then finally, the work narrows down to emphasize 3D Si-based LIB electrodes. In addition, the review also capture how silica are obtained from renewable and biomass sources in order to establish a sustainability niche for silica-based LIB electrodes. The focus of the work is on how pristine silica and silica composites can be 3D printed on substrates, for cathodic and anodic applications in lithium-ion batteries (LIBs). The merits and demerits of most prominent 3D printing techniques were well presented, with emphasis on active material preparation, and operational parameters for each printing technique. The work showed that 3D printing can be used to achieve silica thin films with controlled thickness, since one of the major setbacks of using silica is the problem of homogenous thickness and surface cover. Silica, plus other active materials like LTO, PEDOT, PVP, GO, CNT, clay, TiO2, Fe3O4, and other TMOs can be mixed through various methods and 3D printed to achieve outstanding energy density, power density, capacity and cycle life.
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•3D printing of LIB electrodes was reviewed.•Challenges of 3D printing in LIB electrodes were presented.•Design properties, performance of 3D printed Si-based LIB electrode were presented.
Renewable high‐performance macroscopic functional fibers are prepared by a simple wet‐extrusion and coagulation process of hydrogels of native cellulose nanofibrils. The fibers are functionalized to ...be transparent, conducting, or magnetic and they can host and release guests as payloads. These biobased macrofibers provide a sustainable approach for high‐performance and functional fiber technology in 21st century technologies.
The forest sector plays a key role in meeting the climate change challenge. Forest products and renewable materials are masterpieces in achieving this role. This editorial destails the benefits of ...these forest prodcuts and celebrates the contributions of the authors who submitted their work to this special edition of Forests journal. This edition presents 11 papers, which include the characterization of a new fiber supply, the description of advanced materials and their environmental impact, and an examination of structural products, wood protection, and modifications.
Abstract
The accumulation of petroleum polymers compromises biodiversity and causes environmental problems. Nanocellulose enhances biodegradability and can improve the physical-mechanical performance ...of materials. The objective was to produce and characterize hybrid films composed of bacterial cellulose (BC) and plant nanocellulose from
Eucalyptus
(Euc) or
Pinus
(Pin). Films were produced by the casting method using filmogenic suspensions with different cellulose nanofibrils (CNFs) proportions from both the sources (0, 25, 50, 75 and 100 %). CNFs suspensions were characterized by transmission electron microscopy. The morphology of the films was analyzed using scanning electron microscopy. In addition, the transparency, contact angle, wettability, oil and water vapor barrier and mechanical properties were also evaluated. The contact angles were smaller for films with BC and the wettability was greater when comparing BC with plant CNFs (0.10 °
s
−
1
{\text{s}^{-1}}
for 75 % Euc/25 % BC and 0.20 °
s
−
1
{\text{s}^{-1}}
for 25 % Euc/75 % BC). The water vapor permeability (WVP) of the 100 % BC films and the 25 % Euc/75 % BC composition were the highest among the studied compositions. Tensile strength, Young’s modulus and puncture strength decreased considerably with the addition of BC in the films. More studies regarding pre-treatments to purify BC are needed to improve the mechanical properties of the films.
The continuous production of macroscale filaments of 17 μm in diameter comprising aligned TEMPO-oxidized cellulose nanofibrils (CNFs) is conducted using a field-assisted flow-focusing process. The ...effect of an AC external field on the material’s structure becomes significant at a certain voltage, beyond which augmentations of the CNF orientation factor up to 16% are obtained. Results indicate that the electric field significantly contributes to improve the CNF ordering in the bulk, while the CNF alignment on the filament surface is only slightly affected by the applied voltage. X-ray diffraction shows that CNFs are densely packed anisotropically in the plane parallel to the filament axis without any preferential out of plane orientation. The improved nanoscale ordering combined with the tight CNF packing yields impressive enhancements in mechanical properties, with stiffness up to 25 GPa and more than 63% (up to 260 MPa), 46% (up to 2.8%), and 120% (up to 4.7 kJ/m3) increase in tensile strength, strain-to-failure, and toughness, respectively. This study demonstrates for the first time the control over the structural ordering of anisotropic nanoparticles in a dynamic system using an electric field, which can have important implications for the development of sustainable alternatives to synthetic textiles.
This article demonstrates the development of nanofibrous cloths by electrospinning of renewable materials, i.e., curcumin-loaded 90% cellulose acetate (CA)/10% poly(ε-caprolactone) (PCL), for ...applications in regenerative medicine. The CA is derived from the biomass waste of the oil palm plantation (empty fruit bunch). The nanofiber scaffolds are characterized for the fiber morphology, microstructure, thermal properties, and wettability. The optimized smooth and bead-free electrospun fiber cloth contains 90% CA and 10% PCL in two curcumin compositions (0.5 and 1 wt%). The role of curcumin is shown to be two-fold: the first is its function as a drug and the second is its role in lowering the water contact angle and increasing the hydrophilicity. The hydrophilicity enhancements are related to the hydrogen bonding between the components. The enhanced hydrophilicity contributed to improve the swelling behavior of the scaffolds; the CA/PCL/Cur (0.5%) and the CA/PCL/Cur (1.0%) showed swelling of ~700 and 950%, respectively, in phosphate-buffered saline (PBS). The drug-release studies revealed the highest cumulative drug release of 60% and 78% for CA/PCL/Cur (0.5%) and CA/PCL/Cur (1.0%) nanofibers, respectively. The in-vitro studies showed that CA/PCL/Cur (0.5 wt%) and CA/PCL/Cur (1.0 wt%) nanofiber scaffolds facilitate a higher proliferation and expression of actin in fibroblasts than those scaffolds without curcumin for wound healing applications.
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Juncus is a perennial herb aquatic plant found worldwide, with high reproductive ability in warm regions. It has three-dimensional hierarchical porous triangular networks structures composited of ...tubular fibers. Here, juncus derived nitrogen-doped porous carbon (NDPC) was prepared by mixing juncus and ZnCl
through one-step pyrolysis and activation which is a low-cost, simple, and environmentally friendly method. The NDPC had hierarchical porous structures and a high specific surface area and was applied for supercapacitor and oxygen reduction reaction (ORR). The resulted NDPC-3-800 was prepared by mixing juncus with ZnCl
at a mass ratio of 1:3 and then carbonized at 800°C, it was used as electrode material of a supercapacitor. The supercapacitor exhibited excellent specific capacitance of 290.5 F g
and 175.0 F g
in alkaline electrolyte at the current densities of 0.5 A g
and 50 A g
, respectively. The supercapacitor showed good cycle stability, and the capacitance was maintained at 94.5% after 10,000 cycles. The NDPC-5-800 was prepared by mixing juncus with ZnCl
at a mass ratio of 1:5 and then carbonized at 800°C. It exhibited outstanding ORR catalytic activity and stability attributing to their high specific surface area and abundant actives sites. The juncus can derive various materials for application in different fields.
In this letter, we report a novel biomemristor synapse based on renewable guar gum biopolymers that can dissolve in water easily and obtain a uniform and compact resistive switching layer via ...spin-coating process. Incorporating with well-dispersed tungsten telluride (WTe2) nanosheets exfoliated by natural tannic acid, the fabricated Ag/guar gum-WTe2 nanohybrid/Au biomemristor exhibits a forming-free volatile switching characteristic with low operation voltage (< 0.3 V) and robust uniformity. The device can mimic bio-synaptic functionalities for both short- and long-term plasticity, including excitatory postsynaptic current, paired-pulse facilitation, the transition from short-term plasticity to long-term potentiation, and the forgetting behavior modulation by pulse frequency. The guar gum-WTe2 nanohybrid-based biomemristor paves a promising way to develop biocompatible and environment sustainable artificial synapses for neuromorphic systems.
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