High-performance Nanocomposites Research Articles

Sliding behaviour of carbon nanothread within a bundle embedded in polymer matrix

Interfacial shear strength determines the load transfer efficiency between nanofillers and polymer matrix, and thus the overall mechanical performance of polymer nanocomposites. Through atomistic simulations, this work systematically assessed the sliding behaviours of one-dimensional carbon nanothread (NTH) from a bundle configuration embedded in the poly (methyl methacrylate) (PMMA) matrix. It is found that the functionalized NTH exhibits remarkably enhanced interfacial shear strengths due to the strong mechanical interlocking effect, about an order of magnitude higher than the pristine sample. However, excess volume is generated within a functionalized bundle structure, leading to a weaker non-bonded interaction for a functionalized NTH within the bundle than that only embedded in the polymer matrix. With covalent cross-linking, the surrounding NTHs can be simultaneously dragged out from the PMMA matrix while pulling out the central NTH. Such phenomenon attributes to the filler-filler interactions and filler-matrix interactions. Further studies reveal that no extra free volume is generated within the bundle structure at high temperatures, which retains the effective load transfer efficiency. In comparison, free volume tends to be generated at the interface between NTHs and PMMA matrix at a higher temperature. These findings could be beneficial for fibre design and high-performance polymer nanocomposites with 1D nanomaterials.

High-tech graphene oxide reinforced conducting matrix nanocomposites—Current status and progress

Graphene oxide can be referred to as oxidized graphene. Similar to graphene, oxidized graphene possesses remarkable structural features, advantageous properties, and technical applications. Among polymeric matrices, conducting polymers have been categorized for p conjugated backbone and semiconducting features. In this context, doping, or nano-additive inclusion, has been found to enhance the electrical conduction features of conjugated polymers. Like other carbon nanostructures (fullerene, carbon nanotube, etc.), graphene has been used to reinforce the conjugated matrices. Graphene can be further modified into several derived forms, including graphene oxide, reduced graphene oxide, and functionalized graphene. Among these, graphene oxide has been identified as an important graphene derivative and nanofiller for conducting matrices. This overview covers essential aspects and progressions in the sector of conjugated polymers and graphene oxide derived nanomaterials. Since the importance of graphene oxide derived nanocomposites, this overview has been developed aiming at conductive polymer/graphene oxide nanocomposites. The novelty of this article relies on the originality and design of the outline, the review framework, and recent literature gathering compared with previous literature reviews. To the best of our knowledge, such an all-inclusive overview of conducting polymer/graphene oxide focusing on fundamentals and essential technical developments has not been seen in the literature before. Due to advantageous structural, morphological, conducting, and other specific properties, conductive polymer/graphene oxide nanomaterials have been applied for a range of technical applications such as supercapacitors, photovoltaics, corrosion resistance, etc. Future research on these high-performance nanocomposites may overcome the design and performance-related challenges facing industrial utilization.

Improving Mechanical and Barrier Properties of Antibacterial Poly(Phenylene Sulfide) Nanocomposites Reinforced with Nano Zinc Oxide-Decorated Graphene

Nano zinc oxide-decorated graphene (G-ZnO) was blended with polyphenylene sulfide (PPS) to improve its tensile, thermal, crystalline, and barrier properties. The properties of neat PPS and PPS/G-ZnO nanocomposites were characterized and compared using various tests, including tensile tests, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, evaluation of Escherichia coli inhibition, and barrier performance. The results demonstrated that G-ZnO played a crucial role in heterogeneous nucleation and reinforcement. When the concentration of G-ZnO was 0.3%, the tensile strength, elongation at break, thermostability, crystallinity, and water vapor permeability coefficients (WVPC) approached their maximum values, and the microscopic morphology changed from the original brittle fracture to a relatively tough fracture. In addition, when G-ZnO was added to PPS at a ratio of 0.3%, the tensile strength, elongation at break, and WVPC of PPS were increased by 129%, 150%, and 283%, respectively, compared to pure PPS. G-ZnO endowed the nanocomposites with antibacterial properties. The improvement in barrier performance can be attributed to three reasons: (1) the presence of G-ZnO extended the penetration path of molecules; (2) the coordination and hydrogen bonds between PPS polymer matrix and G-ZnO nanofiller narrowed the H2O transmission path; and (3) due to its more hydrophobic surface, water molecules were less likely to enter the interior of PPS/G-ZnO nanocomposites. This study provides valuable insights for developing high-performance PPS-based nanocomposites for various applications.

Novel Use of Cellulose Based Biodegradable Nano Crystals in the Machining of PPS Composites: An Approach Towards Green Machining

Because of their biodegradable and regenerative properties, cellulose nanocrystals derived primarily from naturally occurring cellulose fibers serve as a sustainable and environmentally beneficial material for most applications. Although these nanocrystals are inherently hydrophilic, they can be surface functionalized to suit a wide range of demanding requirements, such as those associated with the creation of high-performance nanocomposites in hydrophobic polymer matrices. Therefore, the present work deals with the application of cellulose-based biodegradable nanocrystals as a lubricant in the machining of PPS composites. In this study, milling process was considered to investigate the influence of the sustainable lubricating conditions on the machinability indexes of PPS composites. As a novel cooling approach, water-based solutions enriched by cellulose nanocrystals with different reinforcements (0.25%, 0.5%, and 1%) were used over known methods such as MQL, conventional flood, and dry. According to the research outcomes, cellulose nanocrystals-based nanofluids provided satisfying contributions on retarding the tool wear and reducing the cutting temperatures considerably. Despite the surface-related results such as roughness, topography and texture are promising for the developed strategy; further investigations will be useful to determine ideal water-particle concentration to improve the quality of the machined surface.

High-performance flexible nanocomposites with superior fire safety and ultra-efficient electromagnetic interference shielding

High-performance multifunctional polymeric materials integrated with high fire safety, excellent mechanical performances and electromagnetic interference (EMI) shielding properties have great prospects in practical applications. However, designing highly fire-safe and mechanically robust EMI shielding nanocomposites remains a great challenge. Herein, hierarchical thermoplastic polyurethane/cyclophosphazene functionalized titanium carbide/carbon fiber fabric (TPU/CP-Ti3C2Tx/CF) nanocomposites with high fire safety and mechanical strength and toughness were prepared through the methods of melt blending, layer-by-layer stacking and thermocompression. The TPU/CP-Ti3C2Tx showed improved thermal stability. Moreover, the peak of heat release rate and total heat release of the hierarchical TPU sample containing 4.0 wt.% CP-Ti3C2Tx were respectively reduced by 64.4% and 31.8% relative to those of pure TPU, which were far higher than those of other TPU-based nanocomposites. The averaged EMI shielding effectiveness value of the hierarchical TPU/CP-Ti3C2Tx-2.0/CF nanocomposite reached 30.0 dB, which could satisfy the requirement for commercial applications. Furthermore, the tensile strength of TPU/CP-Ti3C2Tx-2.0/CF achieved 43.2 MPa, and the ductility and toughness increased by 28.4% and 84.3% respectively compared to those of TPU/CF. Interfacial hydrogen bonding in combination with catalytic carbonization of CP-Ti3C2Tx nanosheets and continuous conductive network of CF were responsible for the superior fire safety, excellent EMI shielding and outstanding mechanical performances. This work offers a promising strategy to prepare multifunctional TPU-based nanocomposites, which have the potential for large-scale application in the fields of electronics, electrical equipment and 5 G facilities.

Biomimetic construction of hierarchical MXene@PDA@CoFeOx nanohybrids towards efficient fire-safe epoxy nanocomposites with enhanced thermal conductivity and mechanical properties

Developing high-performance MXene-based polymer nanocomposites through a biomimetic method has been a research hotspot. However, it is still an intractable challenge to achieve MXene-based polymer nanocomposites with efficient fire safety, excellent thermal conductivity, and enhanced mechanical properties. Here, inspired by the adhesion of mussels, the hierarchical MXene@PDA@CoFeOx nanohybrid was fabricated by a self-assembly strategy and then employed to prepare epoxy resin (EP) nanocomposites. It has been found that MXene@PDA@CoFeOx can display excellent dispersion and interfacial compatibility in EP matrix. Thermogravimetric analysis shows that only 2.0 wt% MXene@PDA@CoFeOx results in excellent thermal stability and char yield (31.29 wt%) of EP under a nitrogen atmosphere. Combustion tests show that the 2.0 wt% MXene@PDA@CoFeOx confers efficient fire safety to EP. Remarkably, the EP-2.0%MXene@PDA@CoFeOx can obtain an attractive UL-94 rating of V0. Meanwhile, the peak heat release rate (pHRR), smoke factor (SF), and peak CO production rate (pCO) of EP-2.0%MXene@PDA@CoFeOx are dramatically decreased by 33.38%, 55.41%, and 36.84% in comparison to those of virgin EP, respectively. The efficient fire safety of EP nanocomposites is mainly attributed to the barrier effect, dilution effect, and catalytic carbonization effect of hierarchical MXene@PDA@CoFeOx. Furthermore, the MXene@PDA@CoFeOx enables EP to boast enhanced thermal conductivity (improved by 69.14%), impact strength (improved by 13.38%), and flexural strength (improved by 17.60%). This work offers a feasible biomimetic method for fabricating hierarchical MXene@PDA@CoFeOx nanohybrids and preparing efficient fire-safe EP nanocomposites with excellent thermal conductivity and mechanical performance.

Water-Induced Separation of Polymers from High Nanoparticle-Content Nanocomposite Films.

Polymer nanocomposites with high loadings of nanoparticles (NPs) exhibit exceptional mechanical and transport properties. Separation of polymers and NPs from such nanocomposites is a critical step in enabling the recycling of these components and reducing the potential environmental hazards that can be caused by the accumulation of nanocomposite wastes in landfills. However, the separation typically requires the use of organic solvents or energy-intensive processes. Using polydimethylsiloxane (PDMS)-infiltrated SiO2 NP films, we demonstrate that the polymers can be separated from the SiO2 NP packings when these nanocomposites are exposed to high humidity and water. The findings indicate that the charge state of the NPs plays a significant role in the propensity of water to undergo capillary condensation within the PDMS-filled interstitial pores. We also show that the size of NPs has a crucial impact on the kinetics and extent of PDMS expulsion, illustrating the importance of capillary forces in inducing PDMS expulsion. We demonstrate that the separated polymer can be collected and reused to produce a new nanocomposite film. The work provides insightful guidelines on how to design and fabricate end-of-life recyclable high-performance nanocomposites.

Polyvinyl Alcohol Assisted Iron-Zinc Nanocomposite for Enhanced Optimized Rapid Removal of Malachite Green Dye.

Eliminating hazardous contaminants is a necessity for maintaining a healthy environment on Earth. This work used a sustainable method to create Iron-Zinc nanocomposites with polyvinyl alcohol assistance. Mentha Piperita (mint leaf) extract was used as a reductant in the green synthesis of bimetallic nanocomposites. Doping with Poly Vinyl Alcohol (PVA) caused a reduction in crystallite size and greater lattice parameters. XRD, FTIR, EDS, and SEM techniques were used to establish their surface morphology and structural characterization. The high-performance nanocomposites were used to remove malachite green (MG) dye using the ultrasonic adsorption technique. Adsorption experiments were designed by central composite design and optimized by response surface methodology. According to this study, 77.87% of the dye was removed at the optimum optimized parameters (10.0 mg L-1 was the concentration of MG dye at a time of 8.0 min, pH 9.0, and 0.02 g of adsorbent amount) with adsorption capacity up to 92.59 mg·g-1. The dye adsorption followed Freundlich's isotherm model and the pseudo-second-order kinetic model. Thermodynamic analysis affirmed the spontaneous nature of adsorption due to negative ΔGo values. As a result, the suggested approach offers a framework for creating an effective and affordable technique to remove the dye from a simulated wastewater system for environmental conservation.

Synergy of charge capture and transfer by Ni-MOF nanosheets for enhancing energy storage performance of polyetherimide-based dielectric nanocomposites

Polymer-based dielectric nanocomposites with excellent energy storage performance and good thermal stability are essential to meet the demand for dielectric capacitors operating under high-temperature environments. However, there is still a challenge to high-temperature breakdown strength and energy density due to the increase in leakage current with temperature and applied electric field. In this work, Ni-based metal-organic framework nanosheets (Ni-MOFs) are synthesized by a sonication-assisted solution method and introduced into polyetherimide (PEI) to fabricate Ni-MOFs/PEI dielectric nanocomposites. As a result, the nanocomposites containing 2 wt. % Ni-MOFs exhibit a significantly enhanced breakdown strength of 640 kV/mm and a discharged energy density of 6.37 J/cm3 at 150 °C, which are 48% and 228% higher than those of pure PEI, respectively. This enhancement could be attributed to the synergistic effect of charge capture and transfer induced by wider bandgap and π–d conjugation of Ni-MOFs, which not only act as deep traps to capture charges at the interface but also transfer the charges along the in-plane direction to uniform the local electric field, thus reducing the leakage current and conduction loss. This work provides an effective strategy for the design of high-performance dielectric nanocomposites based on polymer.

Optimized Ga-based nanocomposite for superior Li-ion battery anodes

Among the various liquid metals, Ga has unique properties, such as a low melting temperature, fluidity, and non-toxicity. In addition, Ga can alloy with Li to form a Li2Ga phase, which can be applied to high-capacity anodes for Li-ion batteries (LIBs). However, Ga-based materials readily melt and agglomerate during lithiation/delithiation owing to their low melting temperature and high surface energy, resulting in poor cycling stability. In this study, two structural types of Ga, crystalline and amorphous, were selected and electrochemically investigated as LIB anodes. Subsequently, to address the melting and agglomeration issues of the Ga anode, an optimized Ga-based nanocomposite was developed using a novel synthetic concept, namely a solid-state alloying–dealloying process. This process involves an alloying reaction of Ga and Ti to form various Ga–Ti compounds, such as Ga3Ti, Ga2Ti, and Ga3Ti2, and a dealloying reaction with amorphous C to form a nanocomposite comprising evenly dispersed amorphous Ga and Li-inactive TiC in the amorphous C matrix. The Li-inactive TiC and amorphous C matrix in the nanocomposite effectively confined amorphous Ga, thereby preventing the problems caused by its melting and agglomeration during cycling. In addition, an interesting transformation behavior of amorphous Ga into electrochemically stabilized Ga nanocrystallites (approximately 2–3 nm) was demonstrated during cycling, contributing to the high electrochemical performance. The Ga-based nanocomposite exhibited a superior electrochemical performance. This study proposes a better understanding of high-performance Ga-based anodes for LIBs as well as an effective fabrication method for high-performance nanocomposites by solid-state alloying–dealloying.

Polymer Nanocomposites: A Comprehensive analysis and literature survey

Polymer nanocomposites, the amalgamation of polymers and nanoscale fillers, have garnered substantial attention due to their enhanced properties and multifaceted applications. This study delves into the formation process and the intricate structural challenges associated with polymer nanocomposites. By systematically reviewing recent literature, this paper explores the synthesis techniques employed and the hurdles encountered during the creation of these advanced materials. The dispersion of nanofillers within the polymer matrix and the establishment of strong filler-matrix interactions are pivotal factors affecting the structural integrity and overall performance of nanocomposites. Through a comprehensive analysis of these challenges, this study sheds light on the complexities of achieving a uniform and optimized structure. The objective of this research is to illuminate the significance of addressing these structural challenges for the development of high-performance polymer nanocomposites. Employing a combination of experimental synthesis, advanced characterization, and theoretical analysis, this study aims to contribute to the advancement of nanocomposite fabrication techniques. Ultimately, by comprehending and overcoming these challenges, the door opens to harnessing the full potential of polymer nanocomposites for tailored applications in diverse industries.

Optically transparent laminated acrylic composites reinforced with mercerised bacterial cellulose nanopaper

Bacterial cellulose (BC) nanopaper is an important material structure for the production of high-performance cellulose nanocomposites. Here, we report the mercerisation of BC nanofibrils as a route to produce ductile BC nanopaper. Mercerised BC nanopaper was found to possess a ductile response under uniaxial tension, albeit with lower tensile modulus and strength compared to neat BC nanopaper due to the presence of large fraction of disordered cellulose. The impregnation of (mercerised) BC nanopaper with an acrylated urethane resin, followed by lamination with impact-modified acrylic produces optically transparent BC/acrylic composites. At a BC loading of only 8 wt%, the mercerised BC/acrylic composite possessed a flatwise and edgewise Charpy impact strength of 19.0 kJ m−2 and 19.5 kJ m−2, respectively; a 62% and 22% increase over monolithic acrylic. The influence of different alkaline treatments on the morphology, crystallography, mechanical and optical properties of the BC nanopaper, as well as the BC/acrylic composites are juxtaposed in this work.

Preparation of Polyethylene/α-Zirconium Phosphate Nanocomposites via a Well-Controlled Polyethylene-Grafted Interface.

It is a daunting task to prepare polyolefin nanocomposites that contain well-exfoliated nanoplatelets due to the nonpolar and high crystallinity nature of polyolefins. In this research, a robust approach was developed to prepare polyethylene (PE) nanocomposites by grafting maleated polyethylene (MPE) onto pre-exfoliated α-zirconium phosphate (ZrP) nanoplatelets via a simple amine-anhydride reaction to form ZrP-g-MPE. Several variables, including maleic anhydride (MA) content, MPE graft density, MPE molecular weight, and PE matrix crystallinity, were investigated to determine how they influence ZrP-g-MPE dispersion in PE. It was found that grafted PE has a different morphology and that the long PE brushes with medium graft density on ZrP can achieve sufficient chain entanglement and cocrystallization with PE matrix to stabilize and maintain ZrP-g-MPE dispersion after solution or melt mixing. This leads to enhanced Young's modulus, yield stress, and ductility. The structure-property relationship of PE/ZrP-g-MPE nanocomposites and usefulness of this study for the preparation of high-performance polyolefin nanocomposites are discussed.

Shape Memory Graphene Nanocomposites—Fundamentals, Properties, and Significance

Shape memory nanocomposites are excellent smart materials which can switch between a variable temporary shape and their original shape upon exposure to external stimuli such as heat, light, electricity, magnetic fields, moisture, chemicals, pH, etc. Numerous nanofillers have been introduced in shape memory polymers such as carbon nanotubes, graphene, nanodiamonds, carbon nanofibers, etc. Among nanocarbons, graphene has attracted research interest for the development of shape memory polymer/graphene nanocomposites. Graphene is a unique one-atom-thick two-dimensional nanosheet of sp2-hybridized carbon atoms. Graphene has been used as an effective nanofiller in shape memory polymeric nanocomposites owing to its remarkable electrical conductivity, flexibility, strength, and heat stability. Thermoplastics as well as thermoset matrices have been used to form the shape memory nanomaterials with graphene nanofiller. In shape memory polymer/graphene nanocomposites, their shape has been fixed above the transition temperature and then transformed to the original shape through an external stimulus. The inclusion of graphene in nanocomposites can cause fast switching of their temporary shape to their original shape. Fine graphene dispersion, matrix–nanofiller interactions, and compatible interface development can lead to high-performance shape memory graphene-derived nanocomposites. Consequently, this review focuses on an important class of shape memory graphene-based nanocomposites. The fabrication, physical properties, and shape memory actuation of polymer/graphene nanocomposites are discussed. The stimuli-responsive polymer/graphene nanocomposites mostly revealed heat-, electricity-, and light-induced effects. The inclusion of graphene enhanced the physical/covalent linking, shape recovery, shape fixity, flexibility, and crystallization effects in the polymers. Furthermore, potential applications of these materials are observed in the aerospace/automobile industries, civil engineering, and biomaterials.

Self-Healing Nanocomposites—Advancements and Aerospace Applications

Self-healing polymers and nanocomposites form an important class of responsive materials. These materials have the capability to reversibly heal their damage. For aerospace applications, thermosets and thermoplastic polymers have been reinforced with nanocarbon nanoparticles for self-healing of structural damage. This review comprehends the use of self-healing nanocomposites in the aerospace sector. The self-healing behavior of the nanocomposites depends on factors such as microphase separation, matrix–nanofiller interactions and inter-diffusion of polymer–nanofiller. Moreover, self-healing can be achieved through healing agents such as nanocapsules and nanocarbon nanoparticles. The mechanism of self-healing has been found to operate via physical or chemical interactions. Self-healing nanocomposites have been used to design structural components, panels, laminates, membranes, coatings, etc., to recover the damage to space materials. Future research must emphasize the design of new high-performance self-healing polymeric nanocomposites for aerospace structures.

Vulcanization, compounding, thermo-mechanical properties and surface morphology of montmorillonite nanoclay based nitrile rubber nanocomposites

Remarkable importance has been bestowed upon polymer nanocomposites over the last few decades. Recently high-performance nanocomposites based on organic polymer/inorganic fillers have provided a new platform to the investigators in scientific and industrial aspects because of their unique and excellent properties. The main challenge lies in efficient dispersion and alignment of nanoclay into polymer matrix. The nanocomposites provided superior thermo-mechanical properties i.e., flexibility, light weight, good processability with comparatively low cost and several applications in field such as automobile, electrical, safety, and aerospace. The present investigation is devoted on the development of nitrile rubber nanocomposites reinforced with montmorillonite (MMT) nanoclay and other vulcanization and compounding additives like dicumyl peroxide, zinc oxide, stearic acid, di-octyl-phthalate, antioxidant, curing agents etc., and this also study investigated the effect of MMT nano-clay of loading 1, 3, 5 parts per hundred rubber (phr) on the thermo-mechanical properties and morphological aspects of nitrile rubber. Nanocomposites samples were prepared through vulcanization and compounding method using two roll mills, followed by compression moulding. The results revealed that 5 phr content of MMT nanoclay in the nitrile rubber matrix gives the highest tensile strength, tensile modulus and elongation at break according to ASTM standard and thermal stability carried out through thermal gravimetric analysis (TGA). The modification in various properties can be attributed to better interfacial adhesion between nanoclay and rubber matrixes examined by scanning electron microscopy (SEM).

A novel sol-gel strategy for constructing wood fibers and aramid nanofiber nanocomposite with strong, tough and recyclable properties

Recently, biomass-based materials derived from wood processing residues have been developed to resolve the white pollution. However, the poor mechanical strength, weak water resistance, and non-recyclability still limit their practical applications. Aramid nanofiber (ANF) is a promising reinforcement due to the unique structural characteristics and exceptional mechanical properties. Here, a high-performance wood fibers-based nanocomposite was assembled based on chemically-modified wood fiber (CWF) and ANF via a sol-gel strategy with the solvent exchange. The dynamic noncovalent cross-linking with 3D reticular networks between CWF and ANF endow the as-prepared film with high tensile strength of 591.96 ± 11.05 MPa, high toughness of 38.68 ± 2.15 MJ/m3, and excellent solvent resistance. Moreover, the CWF-ANF gel can effectively repair the fractured CWF-ANF film under heating and maintain competitive mechanical properties after several dissolution-reconstruction, which shows the fascinating sustainability potential. Simultaneously, the as-prepared film is considered as a strong substrate to advance excellently conductive and anti-counterfeiting composite with double-layered structures. This effective strategy provides a novel pathway to reuse plant waste resources with competitive mechanical properties and high value-added utilization.

Enhancement of recovered graphite's electrochemical performance during LIB recycling to promote circular sustainable development

The extensive use of lithium-ion batteries (LIBs) has highlighted the issue of their disposal. As LIBs contain hazardous elements, improper disposal endangers the environment and human health. As a result, recycling outdated LIBs is unavoidable. Graphite, a key component of LIB, has substantial environmental consequences, and many graphite production plants are experiencing legal issues worldwide. However, due to its cheap cost and lengthy recovery procedure, it has yet to receive significant attention. LIBs recovery has also become unprofitable and unwanted due to cobalt-free cathode chemistries. In this work, we have attempted to improve the electrochemical performance of recovered graphite during the recovery process to generate a high-performance nanocomposite that can be used to fabricate novel anode material, adding value to the recycling process. The new anode material exhibits 824 mAh g−1 initial discharge capacity and retained 428 mAh g−1 at 0.1 A g−1 after 100 cycles. Furthermore, even at a current density of 2 A g−1, the material retained 355 mAh g−1 reversible capacity post 65 cycles, confirming its potential use as LIBs anode. Finally, we advocate the use of recovered graphite rather than virgin graphite for circular sustainable development.

Intercalated oligomer doubles plasticity for strong and conductive graphene papers and composites

Disordered wrinkles inevitably appear in the fluid assembly process of graphene and heavily depress performances of assembled graphene papers. Achieving high plasticity enables the post modulation to rearrange wrinkles by stretching. Here, we obtain an over 100% improved plasticity by intercalating oligomer into graphene oxide (GO) laminates and fabricate strong, stiff and conductive graphene papers (GPs) via post stretching. The intercalated oligomer activates the mobilization of GO sheets and achieves high plasticity of solid GO papers. The improved plasticity allows high stretching ratio and the post-stretched GP features regular orientation (0.95) of graphene sheets and aligned fine wrinkles. The crystalline GPs have a high tensile strength up to 1.3 GPa, Young's modulus of 92.9 GPa and highly electrical conductivity (1.05 × 105 S m−1). The greatly improved plasticity by oligomer extends the processing capability of graphene materials and the strong and conductive GP can be assembled in high performance nanocomposites with excellent electromagnetic interference shielding effectiveness (EMI SE).

Microstructure evolution of hot-deformed SmCo-based nanocomposites induced by thermo-mechanical processing

• The two-stage phase transition occurred successively, accompanied by grain growth. • Texture formed in 1:5H phase, not in 2:17R phase in SmCo-based nanocomposites. • Proposed a new strategy for forming c-axis textures in nanocomposites. Nanocomposite permanent magnets have ultra-high theoretical magnetic energy products, due to coupling of the soft/hard magnetic phases, inciting strict microstructural requirements. In this study, the microstructure evolution, including the phase transition, morphological changes, and texture formation, of hot-deformed SmCo-based nanocomposites under thermal–stress–strain coupling was characterized to determine a possible strategy for achieving high performance. The SmCo 5 /α-Fe nanocomposites precursor contained fine and dispersed Sm(Fe, Co) 5 and Fe-Co grains and exhibited a two-stage phase transformation accompanied by grain growth. In the early stage of deformation at relatively low temperature, the adjacent Sm(Co, Fe) 5 and Fe-Co phase formed the Sm 2 (Co, Fe) 17 -H phase, which was stable only with small grain sizes. In the high-temperature deformation stage, the Sm 2 (Co, Fe) 17 -H phase transformed into the Sm 2 (Co, Fe) 17 -R phase with large grain sizes. In addition, the strong c -axis texture formed in the Sm(Co, Fe) 5 phase but not in the Sm 2 (Co, Fe) 17 -R phase. Subsequently, the phase transition process and texture formation mechanism were systematically analyzed by transmission electron microscopy. The initiation of a slip system and/or preferential grain growth explained the formation of texture under the action of uniform stress and strain and assisted by dispersed Sm-rich nanograins. The Sm 2 (Co, Fe) 17 -R grains with poor orientations and large grain sizes did not achieve magnetic hardening, which also damage the magnetic properties. According to the results of this work, we also presented a new strategy to prepare high-performance SmCo-based nanocomposites magnets.