查找使用阿拉丁产品的科研文献

Preparation and characterization of modified CNC/waterborne polyurethane composite film

Jun Liu,Yuguo Zhuo,Dawei Yan,Zhu Zhang,Hongfei Jin,Boxuan Xie

To improve the water resistance and mechanical performance of waterborne polyurethane, modified cellulose nanocrystal (CNC) as a kind of environmentally friendly material was added into the solution of waterborne polyurethane by the in-situ polymerization and mechanical blending way, and two different modified CNC/waterborne polyurethane composite films were prepared. The results show that due to the addition of modified CNC, the composite film prepared by in-situ polymerization way showed much better behavior in both water resistance and mechanical properties than that made by the mechanical blending method. When the content of modified CNC was 5% in the composite, the water resistance of the composite film increased by 34.6%. At the same time, the tensile property of the composite film was improved when using in-situ polymerization to fabricate the film, and the value of maximum tensile stress rose by 143.9%.

Rapidly regenerated CNC/TiO2/MnO2 porous microspheres for high-efficient dye removal

Yingkun Song,Min Jiang,Lijuan Zhou,Hongsheng Yang,Jianming Zhang

The cellulose nanocrystal (CNC)/transition metal oxide hybrid porous microspheres usually have high adsorption performance and degradability, and show promising applications in the field of wastewater treatment. However, single metal oxides are limited by the forbidden band width and electron-hole complexation, and often fail to achieve good effluent treatment. Herein, a CNC/manganese dioxide/titanium dioxide porous microspheres are prepared by the combination of bubble template and ionic crosslinking between sodium alginate and Ca 2+ ions as a matrix. Based on the synergistic effect of two kinds of transition metal oxide , the degradation efficiency of CNC/MnO 2 /TiO 2 porous microspheres for methylene blue is as high as 97.0%, showing easy recovery process and rapid regeneration of this material. Besides, its maximum removal of dyes reaches up to 310.2 mg/g, which is much higher than most CNC based adsorption materials. The concept of concerted catalysis can to explain the origin for excellent performance of as-prepared hybrid microspheres.

Characteristics of cotton fabric modified with chitosan (CS)/cellulose nanocrystal (CNC) nanocomposites

Xue Yang,Yanjiao Zhao,Hassan Mussana,Mengistu Tessema,Lifang Liu

The chitosan (CS)/cellulose nanocrystal (CNC) (0, 0.2. 0.5, 0.8 and 1   wt%) nanocomposites were applied as modifier, and then deposited on the surface of cotton fabric via a pad-dry-cure method. The morphology, mechanical, hydrophilicity and ultraviolet (UV)-blocking properties of prepared fabrics were carefully investigated. The results showed that CS/CNC could obviously enhance the UV-blocking property of cotton fabric. CS/CNC0.5 fabric exhibited the most excellent UV-blocking property as well as good washing durability after 30 times water laundering, indicating CS/CNC could be used as efficient and durable UV blocker for cotton fabric. In addition, CS/CNC also can increase the mechanical property of cotton fabric; while decrease the hydrophilicity of cotton fabric.

Synthesis and characterisation of superhydrophobic CNC/ZnO nanocomposites by using stearic acid

Wenkai Zhu,Yan Wu,Yang Zhang

The synthesis of superhydrophobic materials by using inorganic materials and organic renewable materials is a hot topic in academic research. At present, the methods used to prepare superhydrophobic composites are complicated and the hydrophobic modifiers used are expensive. The authors report a simple and efficient method for the synthesis of superhydrophobic composites. At the beginning, the cellulose nanocrystal (CNC)/ZnO nanocomposites were prepared by mechanical blending method, and the surface micro–nano rough structure was constructed. Then the superhydrophobic CNC/ZnO nanocomposites were obtained by hydrophobic modification with cheap low surface energy substance. The results demonstrate that the inorganic–organic nanocomposites have excellent superhydrophobic properties, which indicates that the inorganic–organic nanocomposites have potential applications as hydrophobic additives in coatings and other fields.

Mechanically robust, shape memory, self-healing and 3D printable thermoreversible cross-linked polymer composites toward conductive and biomimetic skin devices applications

Hongjie Bi,Gaoyuan Ye,Hao Sun,Zechun Ren,Tongfei Gu,Min Xu

The current work demonstrates excellent thermal, mechanical, shape memory, and self-healing properties of 3D printable, thermoreversible, cross-linked network composites. The thermoreversible cross-linked networks are composed of Diels-Alder (DA) reversible covalent and transient cross-links, which are formed by thermoplastic polyurethane (TPU) and poly(ε-caprolactone) (PCL). Also, cellulose nanocrystalline (CNC) is utilized as a cross-linking agent. The incorporated CNC, modified with furan (CNC-FA) and maleic anhydride groups (CNC-MAH), exhibits excellent compatibility with TPU/PCL matrix, forming physical and chemical cross-linking structures in the composites. Also, the mechanical properties , thermal stability, and self-healing properties are significantly improved after the addition of modified CNC. In addition, the mechanism of performance enhancement is further analyzed by molecular dynamics simulations. One should note that the mechanically robust and 3D printable self-healing composites enable the fabrication of durable conductive devices and biomimetic skin devices with high mechanical integrity, excellent electrical healing and superior strain-induced fluorescence properties, showing promise in next-generation flexible electronics, encryption devices and electronic skins, and may broaden the variety and applications of 3D-printable materials.

Harnessing CNC-Carrier Nanomaterials for Enhanced Zn2+-Mediated Inhibition of Oomycete Asexual Reproduction

Shunyu Xiang,Meijun Chen,Xingyi Luo,Shicai Zhang,Yang Shen,Xingya Chen,Xiaofeng Zhang,Jing Wang,Huan Tang,Jin Huang,Xianchao Sun

Oomycetes are devastating plant pathogens causing major crop losses, with spores as key infection sources. Inhibiting asexual reproduction, especially sporangium formation and spore release, is crucial for disease prevention. Zn2+ has shown potential in inhibiting oomycete reproduction, but excessive concentrations can cause cytotoxicity and environmental risks. To address this, we used polydopamine (PDA) to complex Zn2+ and form a PDA@Zn2+ coating on cellulose nanocrystals (CNCs) through hydrogen bonding. This ionic nanopesticide (CNC@PDA@Zn2+) enhances effectiveness against oomycetes while reducing dosage and improving biosafety. Bioexperimental results indicate that CNC@PDA@Zn2+ significantly inhibits sporangium formation and spore release from Phytophthora capsici (P. capsici) by suppressing the expression of key sporulation genes (PcATP4, cdc, and G-protein), disrupting spore cell membranes, and altering organelle structures. In vivo, it reduces P. capsici infection on pepper leaves, even in the presence of mycelium. This study highlights CNC@PDA@Zn2+ as a promising biobased nanomaterial for sustainable crop protection.

CNC-Enhanced Carboxymethyl Chitosan Aerogel for Sound Absorption, Flame Retardancy, and Antibacterial Properties

Ting-Ting Li,Yanping Zhang,Kelei Zang,Xiaomeng Wang,Hongli Liu,Jia-Horng Lin,Ching-Wen Lou

In the process of noise pollution control, the limitation of simply relying on increasing the thickness of the sound-absorbing layer has been recognized. Aerogel, due to its lightweight and multifunctional characteristics, has become a research hotspot. However, how to optimize the structure of aerogels to balance sound-absorption performance with other key characteristics remains an important research direction. In this study, by in situ combining zinc borate (ZB) nanoparticles and directional freezing technology, the optimal incorporation amount of nanocellulose (CNC) was explored, and CNC/ZB/carboxymethyl chitosan aerogel with honeycomb pore structure and excellent sound absorption effect was prepared. In order to expand its application in complex scenes, its antibacterial and flame retardant properties were further studied. The experiments demonstrated that the optimized incorporation of CNC not only enhanced the sound-absorbing performance (with the peak of sound absorption coefficient in the 500–1500 Hz frequency band approaching 1), but also maintained an antibacterial rate of over 97% and a combustion rate as low as 0.76 mm s −1 . This sound-absorbing aerogel integrates efficient sound absorption, mechanical strength and toughness, as well as antibacterial and flame-retardant properties, providing a new material design concept for addressing environmental noise and health and safety issues.

Construction of Superhydrophobic Surfaces Enhanced by Silanized-CNC-Assisted PVDF/PDMS Microsphere Coating

Coatings based on polyvinylidene fluoride (PVDF) and poly(dimethylsiloxane) (PDMS)-based polymeric microspheres can be easily fabricated via non-solvent-induced phase separation (NIPS) and electrostatic spraying (ES) techniques. Both techniques are promising strategies for constructing superhydrophobic surfaces on various substrates. However, PVDF and PDMS inherently suffer from severe aggregation, which generates oversized particles and inhomogeneous microstructures. Conventionally, costly and environmentally hazardous dispersants are required to alleviate this issue, severely restricting the industrial scalability and practical application of such coatings. In this work, methyltrimethoxysilane-modified cellulose nanocrystals (Si-CNCs) were introduced as a green multifunctional modifier to tackle these issues. The results revealed that as structural building blocks and dispersants, Si-CNCs inhibited polymer aggregation via electrostatic repulsion and steric hindrance, refined the particle size and formed uniform micro/nano hierarchical structures. Increasing Si-CNC loading further improved polymer dispersion and superhydrophobic performance. Coatings fabricated by ES showed better hydrophobicity than those fabricated by NIPS. ES achieved a water contact angle (WCA) of 160–166° and a sliding angle (SA) near 1° on cotton fabric, while NIPS had a WCA of 153.8–158° and an SA of around 2°. Wood and glass substrates also obtained favorable superhydrophobicity, with WCAs above 150° and SAs below 1°. Furthermore, all modified surfaces exhibited excellent abrasion resistance. This work provides a relatively eco-friendly, environmentally sustainable, scalable and substrate-flexible strategy for fabricating high-performance PVDF/PDMS-based superhydrophobic coatings.

Investigation of a Widely Applicable Process for Extracting Carboxyl-rich Cellulose Nanocrystal (CNC)

Jiang Shuai,Farooq Amjad,Han Fuyi,Liu Lifang

Herein, carboxyl-rich cellulose nanocrystals (CNC) were obtained through a designed TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) mediated oxidation process without any subsequent mechanical treatment, which was proved to be widely suitable for commonly used cellulosic sources, including fibril-like fibers and lignocellulose biomasses. CNC prepared from the acid-free process showed better dispersion stability, less aggregation, higher aqueous UV transmittance and crystallinity compared with that from sulfuric acid hydrolysis process. Furthermore, the residuals in the insoluble precipitate were further conducted ultrasonic treatment and extra CNC was obtained from the oxidized cotton and ramie cellulose while cellulose nanofibril (CNF) was extracted from rice straw and pine powder, attributing to their different native structures. The total yields of nanocelluloses (NCs) were up to 63.2–68.3 %, improving the utilization ratio of the raw materials. This work provided a widely applicable acid- and mechanic-free route in fabricating CNC with inherent carboxyl groups and described an understanding of the relationship between the native structure of raw materials and their products, which is beneficial for improving the application of NCs.

Phosphorylated-CNC/MWCNT thin films-toward efficient adsorption of rare earth La(III)

Zhang Yi,Zheng Xudong,Bian Tingting,Zhang Yuzhe,Mei Jinfeng,Li Zhongyu

Abstract The purpose of the paper is to achieve adsorption and secondary application of La(III) through strong coordination ability of phosphate groups and La(III). Firstly, cellulose nanocrystals (CNCs) were phosphorylated in two solvents (water and molten urea). p-CNC(water)/MWCNT and p-CNC(urea)/MWCNT thin films were successfully synthesized by using p-CNCs as film units based on EISA method. The addition of multi-wall carbon nanotube was to improve thermal stability and repeatability of films and carboxyl groups thereon could also involve in the coordination of La(III). Adsorption experiments show that, at pH 4.0, adsorption capacities of p-CNC(water)/MWCNT and p-CNC(urea)/MWCNT films were 21.23 and 44.71 mg g −1 , with half equilibrium time ( t 1/2 ) of 23.06 and 4.87 min. Repeatability tests show that the adsorption capacities of films remained above 82% of the maximum adsorption capacities after five adsorption–desorption cycles. Graphic abstract

High-tear resistant gels crosslinked by DA@CNC for 3D printing flexible wearable devices

Qingbo Bao,Huijie Li,Youjie Rong,Jianhua Fei,Xiaomin Zhang,Zhuang Zhao,Jian An,Xiaobo Huang

Photocurable gels have broad application prospects in biomedicine, bionics, flexible wearable devices and other fields. However, there are still some problems in the current photocurable gels, such as notch sensitivity, that is, poor tear resistance. In this study, we provided a photocurable gel with excellent tear resistance. The gel prepolymer is mainly composed of hydroxymethylacrylamide (NAM) and cellulose nanocrystals (CNC) modified with dopamine hydrochloride (DA), referred to as DA@CNC. After photocuring, the prepared gels show excellent mechanical properties such as tear resistance, elasticity and toughness. The introduction of DA@CNC not only endows gels with a large amount of energy dissipation through hydrogen bond crosslinking, but also effectively resists crack expansion as a nano-sized reinforcing phase, which greatly improves the tear resistance of the gels. Even at a 40 % gap, the elongation at break of the gel can still reach 1445 %. In addition, the DA can endow the gel with good electrical conductivity and excellent sensitivity (GF = 23.8). Some flexible wearable devices like finger sleeve and wristband can be customized by photocurable 3D printing using the gel with high toughness. This high-performance gel has great application potential in flexible wearable devices.

Multiscale investigation of CNC-stabilized foams: From interfacial design to energy-relevant fluid displacement

Tianhan Xu,Wenhua Zhao,Gaowen Wang,Haonan Wang,Lihui Wang

This study investigates the mechanisms of enhanced oil recovery using a cellulose nanocrystal (CNC)-stabilized foam system. A systematic approach—encompassing foam characterization, scanning electron microscopy (SEM), interfacial tension and wettability measurements, microfluidic displacement visualization, and low-field nuclear magnetic resonance (LF-NMR) analysis—was employed to evaluate the CNC-enhanced foam system. The results demonstrate that the optimized formulation improved foamability and stability, with foam volume and half-life increased by 15.7% and 35.2%, respectively. The incorporation of CNCs reduced the contact angle from 64.9° (conventional system) to 49.6°, indicating enhanced wettability alteration capability. Real-time microfluidic displacement experiments and LF-NMR analysis revealed that the CNC-enhanced nanofluid-assisted water alternating gas (NWAG) process increased the local sweep efficiency to 47.21% and improved micro-pore recovery by 28.5 percentage points. The NWAG process achieved an average ultimate oil recovery of 50.5%, demonstrating a 15.1 percentage-point improvement compared with conventional WAG injection.