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Two types of cellulose nanofibrils (CNFs) were isolated from cotton linter fibers and hardwood fibers through mechanical fibrillation methods. The dialdehyde cellulose nanofibrils (DACNFs) were prepared through the periodate oxidation method, and their morphological and structural properties were investigated. The characteristics of the DACNFs during the concentration process were also explored. The AFM analysis results showed that the mean diameters of wood fiber-based CNFs and cotton fiber-based CNFs were about 52.03 nm and 69.51 nm, respectively. However, the periodate oxidation treatment process obviously reduced the nanofibril size and destroyed the crystalline region of the nanofibrils. Due to the high crystallinity of cotton fibers, the cotton fiber-based DACNFs exhibited a lower aldehyde content and suspension stability compared to the wood fiber-based DACNFs. For the concentration process of the DACNF suspension, the bound water content of the concentrated cotton fiber-based DACNFs was lowered to 0.41 g/g, which indicated that the cotton fiber-based DACNFs could have good redispersibility. Both the wood fiber-based and cotton fiber-based DACNF films showed relatively good transmittance and mechanical strength. In addition, to the cotton fiber-based DACNF films had a very low swelling ratio, and the barrier water vapor and oxygen properties of the redispersed cotton fiber-based DACNF films decreased by very little. In sum, this study has demonstrated that cotton fibers could serve as an effective alternative to wood fibers for preparing CNFs, and that cotton fiber-based DACNFs have huge application prospects in the field of packaging film materials due to their stable properties during the concentration process. [ABSTRACT FROM AUTHOR]

The challenge in energy depletion and environmental pollution urgently demands green and sustainable materials as a new material application platform. Nanocellulose (NC) derived from abundant and renewable resources has been considered as a versatile and sustainable substrate and scaffold to engage various applications. Recently, design and fabricate conductive polymers (CPs)/NC composites as functional electronic devices have received tremendous attention. In this mini review, we start with a brief introduction about the category of nanocellulose, CPs and the preparation strategy of CPs/NC conducive composites followed by discussing the factors that determine the electrical conductivity. Then, we reviewed different CPs/NC composites systems and cited representative electronic application examples including sensors, supercapacitors, lithium-ion batteries. Finally, we proposed current challenges, existing problems and further perspectives and opportunities of CPs/NC conductive composites. [ABSTRACT FROM AUTHOR]

The fast growth of micro-flexible electronic devices has increased the amount of heat generated and electronic waste, which has increased the demand for eco-friendly nanocellulose-based composites with great flame resistance and strong thermal conductivity. Nevertheless, creating appropriate thermally conductive fillers and enhancing the flame retardancy of materials based on nanocellulose remain extremely difficult tasks. This study describes the production of extremely in-plane oriented composite films using TEMPO-oxidized nanocellulose (TOCNF) as the matrix, boron nitride nanosheets (50 wt% BNNS@PDA) as the filler for thermal conductivity, and a small number of phosphorus lignin nanoparticles (2 wt% PL) as an auxiliary filler. First, the orderly organization of thermally conductive fillers in the composite film may be achieved using one-step ball milling, stripping, and non-covalent modification of hexagonal boron nitride, offering an efficient thermal conductivity channel to raise thermal conductivity. After filling in PL (2 wt%), due to the highly compact oriented structure and rich flame-retardant functional groups, the thermal conductivity and flame-retardant properties of the composite film are improved at the same time. The final results demonstrate that the composite film exhibits a high thermal conductivity of 23.49 W mK−1. Compared with a pure nanocellulose film, the TOCNF/BNNS@PDA/PL composite film has a better flame retardant effect and thermal stability. In addition, the composite films show satisfactory flexibility and mechanical properties due to their tight structure and strong interfacial interactions. In conclusion, this work provides a feasible solution for the application of nanocellulose-based thermal conductivity and flame-retardant dual-function composites in thermal management applications for next-generation flexible electronic devices. [ABSTRACT FROM AUTHOR]

To shield significantly serious radiation pollution and reduce fire disasters, fire-retardant MXene-based electromagnetic interference (EMI) shielding nanocomposites featuring superb mechanical properties are highly desired, but remain a major challenge to prepare. Here, we propose a Janus structural engineering strategy to manufacture all-natural cellulose nanofiber (CNF)/montmorillonite (MMT)-supported MXene papers (CMMPs) using a sequential deposition followed by hot-pressing. Inspired by natural nacre, MMT nanosheets are incorporated into CNFs to construct a substrate layer with a "brick-mortar" layered structure that serves to provide mechanical properties, while the independent MXene layer ensures electrical conductivity. The resultant CMMPs exhibit extraordinary mechanical performances involving a mechanical strength of 272.7 MPa and Young's modulus of 10.8 GPa, high electrical conductivity, and a superb EMI shielding effectiveness of 56.1 dB and EMI SE/t of 19 140.8 dB cm−1. Moreover, the designed CMMPs possess impressive flame-retardant and electro-/photothermal heating features, demonstrating their reliability, safety, and versatility. Therefore, such high-performance CMMPs developed by a facile and sustainable preparation strategy possess substantial application prospects in EMI shielding, thermal management, and fire protection. [ABSTRACT FROM AUTHOR]

The hydrogen bond-riched precursors were prepared by mixing melamine and cyanuric acid in aqueous phase. Subsequently, the porous carbon nitride (g-C3N4) materials (MC-s-CN) with three-dimensional lamellar curl stacks were prepared by high temperature polymerization. The effect of hydrogen bonds within the precursor on the catalytic performance during the polymerization process was investigated. The results showed that the introduction of hydrogen bonding greatly reduced the blocky stacking of g-C3N4 material and increased its specific surface area to 74.111 9 m²/g, which was 8.7 times that of traditional carbon nitride M-CN. The better photogenerated carrier transport rate and lower complexation rate of MC-s-CN were further proved by fluorescence spectroscopy, photocurrent and electrochemical impedance tests. Finally, the degradation effect of simulated rhodamine dye wastewater was 12.52 times higher than that of traditional method. Then, the nanocelluloses oxidized by 2,2,6,6-tetramethylpiperidine oxide were used as the skeleton materials, and the composite aerogel materials(CN-TCA) with large specific surface area and excellent adsorption performance were successfully prepared by directional freezing relying on the cross-linking of intermolecular hydrogen bonds. The CN-TCA was tested to has good photocatalytic degradation performance, and the degradation rate of rhodamine solution reached 91% under 120 min visible light irradiation. Additionally, the CN-TCA had great recycling performance, and the degradation effect was still 94.08% in the original state after five cycles. [ABSTRACT FROM AUTHOR]