Cellulose最新文献

The water-soluble tetraphenylethylene derivatives bearing sulfonic acid groups, namely TPE1S, TPE2S, TPE3S, and TPE4S were synthesised. These derivatives exhibit aggregation-induced emission (AIE) behavior, and fluorescence is also detected in dilute aqueous solution under UV irradiation. Furthermore, these compounds display slightly photochromism in both dissolved and solid states. When applied to modified cotton fabric substrates, the compounds exhibit significant photochromic properties due to the interaction force with the fibers. The photochromic behavior of the material can be modulated by external stimuli such as light, temperature, and humidity. The material undergoes complete decolorization within least 3300 s under dark conditions, while green light irradiation accelerates the process to 20 s. A discernible change in imaging color occurs after 18 h of storage at − 20 °C. At 50 °C, the color fades completely within 60 s. These features endow the materials with the potential for light-activated multicolor fluorescent patterning, information encryption, anti-counterfeiting, and smart textiles.

Graphical abstract

Cellulose pulp (CP) is composed mainly of cellulose which is one of the most useful and sustainable natural polymers. Cellulose-based materials, such as completely dispersed nanofibers and water-soluble cellulose, are transparent in water. Additionally, chemical modification of CP has been employed as a pretreatment for the preparation of nanofibers and to impart absorption properties derived from anionic functional groups. However, little is known about chemically modified CPs comprising micron-scale fibers that are transparent in water.In this study, we synthesized transparent sulfated cellulose pulp (TSCP) that exhibits good dispersion stability, high transparency in water, and highly swollen fiber structures. The sulfation method involved heating sulfamic acid and urea supported on CP. TSCP synthesized using a sulfamic acid amount relative to CP (Q) of 18.5, a molar ratio of urea to sulfamic acid (R) of 0.80, and a reaction temperature of 140 °C exhibited the highest total light transmittance (94.7%) in water, a degree of polymerization (535), and amount of sulfate groups (1.73 mmol/g). Polarization microscopy confirmed that most TSCP fibers swelled in water along the fiber width direction. The structure of hydrous-state TSCP was further confirmed using low-vacuum scanning electron microscopy. The maximum fiber width of the swollen TSCP reached 122 μm, which was approximately six times than that of CP. The crystallinity was equivalent to that of the original CP with a Cellulose I-type crystalline structure. This transparent, hydrous-state TSCP, comprising predominantly swollen CP fibers, demonstrates potential for applications as a transparent material.

To enhance the bulk butyrylation and flowability of thermoplastic lignocellulose (TPLC) ultimately to be produced by reactive extrusion, understanding the role of quaternary ammonium salts (quats) as a pretreatment of Aspen Wood Flour (AWF) was essential. This study investigated the adsorptive nature of AWF treated with two distinctly different quaternary ammonium surfactants based on their hydrophilicity to improve the extent of butyrylation, filling a gap in knowledge related to how they associate with lignocellulosic species in a varying acidic environment. The pretreatment effectiveness of the two surfactants was evaluated based on their ability to enhance the reactive effectiveness of butyric anhydride with the resulting improvements reported by a visual adsorption test using Congo Red dye, BET surface area analysis, colorimetric titration, contact angle measurement, electrophoretic mobility testing, and elemental analysis. Adsorption efficiency significantly improved from 1.4% for the untreated AWF to peak values of 62.8% (0.70 mmol/g CTAB) and 87.5% (0.35 mmol/g Hyamine). BET analysis revealed increased surface areas, notably peaking at 13.63 m²/g (CTAB) and 14.79 m²/g (Hyamine) at optimal quat concentrations. Butyrylation mirrored these trends, reaching maximum butyryl contents of 7.67 mmol/g (CTAB) and 7.93 mmol/g (Hyamine) compared to 0.25 mmol/g for the untreated AWF. The more hydrophilic surfactant was more likely to increase surface area to the benefit of the butyrylation reaction whereas the hydrophobic surfactant accumulated on the fibrous surface as a coating that closed over pores and reduced surface area, as well as more effectively decreased the negative charge of the acidified lignocellulose.

What happens when nanocellulose meets liquid metal? Nanocellulose (NC), characterized by its high surface area, unique self-assembly behavior, and diverse chemical modification possibilities, provides a versatile platform for innovative and eco-friendly flexible electronics. This versatility is further amplified by the introduction of liquid metals (LMs), whose fascinating metallic and liquid natures create synergistic opportunities for advanced nanocellulose-based devices. This review aims to comprehensively examine the synergistic potential of nanocellulose-liquid metal interfaces in electronics, detailing recent advancements, emphasizing the importance of interfacial engineering for performance enhancement, and outlining future research directions and applications.

This study investigated the production of cellulose nanofibrils (CNFs) from partially delignified sugarcane bagasse (SCB), focusing on the effects of residual lignin on TEMPO oxidation and CNF properties. Through a comprehensive assessment of SCB processing into CNFs, we explored the correlations between initial lignin content (15–24 wt%), the amount of NaClO (25–50 mmol/g substrate), and the resulting chemical, morphological, and surface modifications. Regardless of the initial lignin content, oxidizing agent level, or type of mechanical treatment (ultrasonication or microfluidization), CNFs with average lengths of ~ 600–800 nm were obtained. However, in substrates with higher initial lignin content (24 wt%), increasing the NaClO concentration from 25 to 50 mmol/g substrate enhanced fibrillation but reduced the average CNF length from 813 to 665 nm. In contrast, no significant differences in fibrillation were observed when using 25 or 50 mmol NaClO/g substrate in samples with lower initial lignin content (15 wt%). Overall, TEMPO oxidation reduced lignin levels to 5–7.5 wt%, despite substantial differences in the starting materials. Substrates with higher initial lignin content yielded lower amounts of carboxylated groups, likely due to the oxidizing agent being consumed in lignin removal rather than cellulose oxidation. Morphological characterization of the substrates before and after TEMPO oxidation highlighted the critical role of this step in modifying fiber structure, which directly correlated with fibrillation efficiency. Zeta potential and rheological analyses highlighted the potential of CNFs produced from a single-step delignification process for high-value applications such as rheology modifiers, hydrogels, and films.

This study explores the development of sodium carboxymethylcellulose/carbon nanotube composite coatings for sustainable water sensors. Sodium carboxymethylcellulose (NaCMC), a biodegradable biopolymer, was used as a dispersing matrix for carbon nanotubes (CNT), forming a stable conductive composite. Resistance was analysed in a CNT concentration range of 5–95 wt%, with a percolation threshold at ~ 9.14 wt%. The water interaction was examined under high humidity, droplet deposition, and in full immersion. Coatings with a low CNT content exhibited significant resistance changes, while higher CNT concentrations (> 50 wt%) provided greater stability. Mechanical durability was assessed in abrasion and bending tests, revealing high structural integrity. After 35 cycles of abrasion, the coating resistance increased by ~ 65%, while bending resulted in minor resistance variations, below 1% for inward bending and less than 3% for outward bending. In addition to experiments, semi-empirical and atomistic simulations have revealed that NaCMC hinders the electron transport in individual CNT, increasing the coating resistance. However, even a small amount of water can screen this effect. The presence of NaCMC on CNT junctions, which play a crucial role in charge transport within CNT coatings, can enhance or reduce their transport properties, depending on the junction type. The calculations have also shown that NaCMC, because of its rigidity, binds weakly to CNT. These findings highlight NaCMC/CNT composites as promising materials for green electronics, including humidity sensors and water-sensitive conductive coatings.

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Efficient and sustainable strategies are required to mitigate several environmental hazards that are caused by oil spill incidents. In this scenario, we developed hierarchical cotton nonwoven fabrics for oil spill cleanup using fly ash and n-octyltriethoxysilane (OTES). Fly ash particles were pulverized to reduce their average size to 560 nm. It was observed that an increase in fly ash concentration up to 20%, led to higher areal density, fabric thickness, and add-on percentage, while reducing fabric porosity and mean pore size of the cotton nonwoven fabric. Surface characterization was done using SEM and FTIR, which confirmed the successful fly ash deposition and OTES coating. The OTES coating led to the creation of a hydrophobic cotton surface with a water contact angle (WCA) of 128.05°. Further deposition of fly ash particles increased the WCA and at higher fly ash concentrations (up to 10%), the fly ash/OTES coated cotton nonwoven fabric exhibited superhydrophobic behaviour. The fly ash/OTES-coated samples demonstrated excellent oil sorption capacities of 15.11 g/g for vegetable oil and 20.11 g/g for engine oil. Moreover, they achieved excellent oil–water separation efficiencies of up to 99% for vegetable oil and 99.5% for engine oil. Milled fly ash particles contributed to higher oil sorption and oil/water separation performance compared to unmilled particles. This study underscores the potential of fly ash/OTES-coated cotton nonwoven fabrics as cost-effective, reusable, and environmentally friendly materials for efficient oil recovery in spill scenarios.

Daytime radiative sky cooling (DRSC) is an emerging sustainable technology that enables emission-free heat management. Incorporating radiative cooling materials into building envelopes has the potential to reduce reliance on electrical cooling. Despite the process, developing radiative cooling materials that are both high-performing, cost-effective, and biodegradable continues to pose a challenge. In this work, a natural mineral (wollastonite) was strategically incorporated into a porous cellulose acetate (CA) film through a simple and effective electrospinning technique combined with non-solvent induced phase separation. The porous structure possessed substantial roughness of the fibers, which provides more scattering sites. Benefit from porous structure and the wollastonite-derived SiO₂ particles, the porous CA/wollastonite-based-SiO₂ film (CWSF) shows an ultra-high solar reflectivity of 98.6% and an infrared emittance of 90.1%, endowing it with outstanding radiative cooling performance. During the outdoor experiment, the CWSF achieved a 7.3 ℃ below ambient temperature drop at the solar irradiance of 823.6 W m⁻². In addition, the film was modified by simple vapour phase deposition to obtain hydrophobic properties, thereby supporting its durability for long-term outdoor use. In addition, the simulation results indicated that the film on building envelopes (side walls and roof) potentially show its good energy efficiency and sustainable performance compared to baseline building consumption. This energy-free cooling material with simple preparation process and exceptional performance provide a viable pathway to design high-performance cooling structural materials and sustainable building radiative cooling materials for large-scale applications.

Graphical Abstract

The high-value utilization of waste plant fibers enhances resource efficiency, reduces environmental pollution, and promotes sustainable development. This study investigates four types of waste fibers—bamboo powder (BP), wood powder (WP), ramie fiber (RF), and waste paper fiber (WF)—as reinforcements in composites, modified through two synergistic approaches. Recycled high-density polyethylene (rHDPE) serves as the matrix. The results show that the WF/rHDPE composites exhibit 18.5% and 36.3% improvements in tensile and bending strength, respectively, compared to rHDPE. After NaOH pretreatment and modification with dopamine and KH570, the 24 h water absorption rate drops to 0.09%, with significant reductions in the other composite’s water absorption. Following NaOH pretreatment and modification with nano-SiO₂ and KH570, the crystallinity of WF/rHDPE and BP/rHDPE increases by 9.12% and 12.8%, respectively, while their 24 h water absorption rates are reduced to 0.11% and 0.3%. Both modification methods significantly enhance mechanical properties and interfacial bonding.

This study compares the mechanical and physical properties of unidirectional long (0°, 0°/90°) and woven false banana fiber reinforced composites with and without the addition of crystalline nanocellulose particle (CNC). The study focused on identifying the composite with superior mechanical properties for structural, industrial, and biomedical applications, including prostheses and orthotics. Polyester resin, false banana fibers, and the byproducts of sugar milling factories were the primary raw materials. The CNC fillers were chemically extracted from byproducts of sugar. To study the mechanical strength of unidirectional and woven false banana fiber-reinforced composites, tensile, compression, flexural strength, and void content tests were conducted using the appropriate ASTM standards. The effect of CNC fillers on the properties of both composites was analyzed. For the 0° unidirectional false banana fiber orientation, the measured tensile, flexural, and compression strengths were 98.83 MPa, 161.60 MPa, and 92.79 MPa, respectively. For the 0°/90° unidirectional false banana fiber orientation, the measured tensile, flexural, and compression strength were 55.99 MPa, 168.81 MPa, and 88.64 MPa, respectively. For the woven false banana fiber composite, the measured tensile, flexural, and compression strength were 48.99 MPa, 122.52 MPa, and 82.61 MPa respectively. The woven false banana fiber composite generally had lower mechanical strength, reduced failure strain, and increased void content compared to unidirectional long false banana fiber composites. On the other hand, adding crystalline nanocellulose particle fillers significantly improved the average tensile strength of unidirectional and woven false banana fiber composites by 16.28% and 18.13%, respectively. The findings obtained from this study are an excellent resource for developing high-performance natural composite structural components and industrial and bio-medical applications, including prostheses and orthotics devices.