查找使用阿拉丁产品的科研文献

Flexible Cellulose/BaTiO3 Nanocomposites with High Energy Density for Film Dielectric Capacitor

Chenggang Zhang,Yanan Yin,Quanling Yang,Zhuqun Shi,Guo-Hua Hu,Chuanxi Xiong

Regenerated cellulose/BaTiO3 nanocomposite films were fabricated by incorporation of BaTiO3 nanoparticle (BTNP) or BaTiO3 nanofiber (BTNF) in regenerated cellulose (RC) via simple blending in aqueous NaOH/urea solution. The results showed that a proper addition of BTNP or BTNF could improve the dielectric constant, breakdown strength, energy density of RC and reduce the dielectric loss simultaneously. Meanwhile, RC-BTNF composites exhibited better dielectric and mechanical properties than RC-BTNP. Especially, the RC-2BTNF composite film with 2 vol % BTNF exhibited an ultrahigh discharged energy density of 13.14 J/cm3 at a breakdown strength of 370 MV/m. Moreover, the discharged energy density of 9.45 J/cm3 at 300 MV/m of RC-2BTNF is the highest discharged energy density of reported polymer-based dielectric films at 300 MV/m (closed to actual electric field strength when film capacitors work). Therefore, these flexible cellulose-based dielectric materials are promising in the field of novel high-performance film dielectric capacitor.

Fluorescent Microspheres Based on Sodium Carboxymethyl Cellulose Hydrogel for Optical Temperature Measurement

Bin Li,Fan Zhang,Xin Yan,Xuenan Zhang,Yong Zhao,Tonglei Cheng

Enhanced Conductivity of Anion-Exchange Membrane by Incorporation of Quaternized Cellulose Nanocrystal

Xia Cheng,Jianchuan Wang,Yunchuan Liao,Cunpu Li,Zidong Wei

High ion conductivity of anion-exchange membrane is essential for the operation of alkaline anion-exchange membrane fuel cell. In this work, we demonstrated an effective strategy to enhance the conductivity of anion-exchange membrane (AEM), by incorporation of quaternized cellulose nanocrystal (QCNC) for the first time. Morphology observation demonstrated a uniform distribution of QCNC within QPPO matrix, as well as a clear QCNC network, which led to significant enhancement in hydroxide conductivities of composite membranes, for example, 2 wt % QCNC/QPPO membrane possessed a conductivity of 160% (60 mS cm–1, @80 °C) of that of QPPO. Furthermore, H2/O2 cell performance of membrane electrode assembly based on 2 wt % QCNC/QPPO AEM showed an excellent peak power density of 392 mV cm–2 at 60 °C without back pressure, whereas that of neat QPPO AEM was only 270 mV cm–2.

Protective coating of paper works: ZnO/cellulose nanocrystal composites and analytical characterization

Minghao Jia,Xiaogang Zhang,Jiajia Weng,Jie Zhang,Meifang Zhang

Coating of ZnO-cellulose composites on paper surface has potential technological applications. With this motivation, a simple approach of synthesizing ZnO nanoparticles in cellulose nanocrystals (CNC) by in-situ solution casting is reported in this work. The surface morphology of ZnO nanoparticles combined with cellulose fibers and the distribution of these ZnO-cellulose composites on the paper surface were characterized by scanning electron microscopy. The results showed that ZnO nanoparticles are easily and uniformly dispersed in the CNC. The ZnO-cellulose composite nanofluids were prepared by dispersing the composites in isopropanol as a base fluid. To determine the protective potential of these coatings, the chemical and mechanical properties of coated papers after dry heat and UV accelerated aging were measured. Also, a good color stability of the paper coated by the nanocomposites was observed through colorimetric measurements . The paper coated with ZnO-cellulose composites was found to possess antibacterial and antifungal activity against five common fungi (Aspergillus niger, Aspergillus Versicolor, Rhizopus nigricans, Saccharomycetes, Mucor) observed in the archive or museum and two bacteria (Staphylococcus aureus and Escherichia coli) in common life.

Transition metal assisted ionothermal carbonization of cellulose towards high yield and recycling

Gao Xiaoru,Yu Yuxiu,He Qian,Li Haojie,Liu Yaodong

A sustainable natural polymer, cellulose, has been used as precursor for producing carbonaceous materials. Ionothermal carbonization (ITC) in ionic liquid (IL) could transform biomass into functional carbon materials at a relatively low temperature. In order to improve the ITC carbon yields and structures, the first raw transition metal chlorides were added into IL, 1-Butyl-3-methyl-imidazole chloride (BmimCl), and their catalyzing effects were compared. It is found that the catalyzing effects of transition metal chlorides are mainly correlated to their cation size. With the addition of 0.5wt% NiCl 2 (based on IL), a high carbon yield of 94wt% is obtained. Additionally, the bio-based carbonaceous materials exhibit a higher graphitization degree with the addition of metal chloride. Furthermore, the IL shows good cyclability, and the carbon yield remains to be higher than 80 wt% after 5 cycles.

Ruthenium trichloride catalyzed conversion of cellulose into 5-hydroxymethylfurfural in biphasic system

Lishi Yan,Ruoshui Ma,Huaixin Wei,Liangzhi Li,Bin Zou,Yiwen Xu

The production of 5-hydroxymethylfurfural (5-HMF) from cellulose catalyzed by a series of transition metal chlorides (i.e. FeCl 3 , RuCl 3 , VCl 3 , TiCl 3 , MoCl 3 and CrCl 3 ) was studied in biphasic system. RuCl 3 was the most efficient catalyst among these transition metal chlorides for 5-HMF production, and resulted in both the highest yield of 83.3% and selectivity of 87.5% in NaCl-aqueous/butanol biphasic system. XRD analysis and FTIR spectroscopy were applied to further characterize the RuCl 3 catalyzed cellulose slurries to reveal the catalytic reaction mechanism. Results demonstrated that RuCl 3 enhanced the decrystallization and cleavage of C O C bonds in cellulose, promoted the subsequent dehydration of glucose into 5-HMF, while suppressed the glucose retro -aldol reaction to byproduct lactic acid. In addition, with the assistance of NaCl-aqueous/butanol biphasic system, 5-HMF further degradation was limited and thusly maintained a desired 5-HMF yield. This proposed approach provides an efficient strategy for one-pot conversion of cellulose into 5-HMF.

Regulation of early hydration and microstructure of cement slurry by cellulose nanofibers

Kaiqiang Liu,Wenli Tang,Lieqiang Luo,Guihai Li,Haiping Wang,Xingguo Zhang

In this study, cellulose nanofibres (CNFs) with different structures were prepared using ball-milling and 2,2,6,6-tetramethylpiperidine-1-oxyl-mediated (TEMPO) oxidation. Then, microcalorimeter, scanning electron microscope, electrical conductivity, and micro-CT were used to investigate the interaction mechanisms between the CNFs and cement slurry. The results showed that the combination of ball-milling and TEMPO oxidation produced CNFs with carboxyl functional groups. When the NaClO concentration was 2 mmol/g and oxidation time was 2 h, the carboxyl content on the surface of the nanofibres was 0.0856 mmol/g. Based on the hydration rate and electrical conductivity results, the carboxylated CNFs reduced the hydration rate of the cement slurry and delayed the exothermic peak by 0.5–2.3 h. The decrease rate of the electrical conductivity of the cement slurry during transition stage increased from 2.805 to 3.543–5.142 mS/(cm·h). The electrical conductivity of the solid–liquid two-phase cement slurry was mainly provided by the pore solution. The decrease in the electrical conductivity of the cement slurry during the transition stage could mainly be attributed to the formation of hydration products that changed the microstructure of the cement slurry from ‘dispersed particles’ to a ‘gel grid’ during the hydration acceleration stage, the porosity and pore connectivity of cement slurry are reduced. The zeta potential results indicate that CNF in the cement slurry provides a location for the nucleation and growth of early hydration products through adsorption and bridging effects, changes the microstructure of the cement slurry, and accelerates the transition from liquid to solid state.

Environmentally Friendly Nanofiber Cellulose From Durian Rinds: A Sustainable Alternative Biomass Resource

Nyoman Puspa Asri,Minarni Wartiningsih,Chintya Gunarto,Antonius Jimmy Widagdo,Yohannes Somawiharja,Yustia Wulandari Mirzayanti,Jia-Ming Chern,Suryadi Ismadji

A novel, efficient, and eco-friendly sustainable process has been developed for the extraction of cellulose nanofibers (CNF) from durian rinds. The method utilizes low-molecular-weight 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as an oxidation agent, in conjunction with sonication treatment, resulting in a significant reduction of processing time and energy consumption compared to conventional techniques. Various delignification methods and sonication times were investigated. For delignification, a sodium hydroxide solution (10%, w/v) at a biomass-to-solvent ratio of 1:30 resulted in the highest cellulose content of 82.07% in cellulose durian rind powder. In addition, the yield of durian rind-based CNF from sonication treatment was found to be as high as 96.26%. The CNF exhibited exceptional characteristics, including a diameter ranging from 8 to 50 nm and a length of several micrometers. This sustainable and environmentally friendly approach demonstrates significant potential for the valorization of agricultural waste into high-performance nanocellulose materials, contributing to the advancement of sustainable materials and applications.

Functionalization of cellulose with hyperbranched polyethylenimine for selective dye adsorption and separation

Zhu Wenjing,Liu Lin,Liao Qian,Chen Xuan,Qian Zhouqi,Shen Junyan,Liang Junlong,Yao Juming

Cationic hyperbranched polyethylenimine (hPEI) was covalently linked onto the backbone of cellulose molecules via forming Schiff base structure between the amino groups of hPEI and the aldehyde groups on the chemically oxidized cellulose surface. The functionalized hPEI-CE possessed available active sites, and its adsorption behavior to anionic dye congo red (CR) and cationic basic yellow 28 (BY28) in aqueous solution was investigated. The hPEI-CE interacted with the two dyes, exhibiting sharp response to solution pH and ionic strength. The adsorption process was well dominated by the pseudo-second-order kinetic model. And the hPEI-CE following the Langmuir isotherm model, had a maximum adsorption capacity of 2100 mg g −1 for CR and 1860 mg g −1 for BY28, respectively. Further, the adsorption performance of six dyes onto the hPEI-CE was studied, which showed high adsorption capacities for CR, BY28, brilliant blue 133 (BB133), and reactive red, but very low adsorption for cationic bright yellow 7GL (7GL) and eosin Y (EY). The different adsorption performances for different dyes indicated the selective adsorption of the hPEI-CE for dyes owing to their different distribution coefficient ( K ) defining as the partition of dyes between hPEI-CE and water. Based on the unique selective adsorption, the mixtures of dyes, such as BB133-CR, BB133-BY28, BB133-7GL, and CR-7GL, were separated successfully using hPEI-CE.

Ionic Liquids Grafted Cellulose Nanocrystals for High-Strength and Toughness PVA Nanocomposite

Li Wang,Jie Hu,Yunxiao Liu,Jie Shu,Hao Wu,Zhaozhao Wang,Xiaolong Pan,Ning Zhang,Lijuan Zhou,Jianming Zhang

The surface functionalization of cellulose nanocrystals (CNCs) is of significant importance for promoting its diverse applications. However, the efficient strategy reported so far for cation functionalization of CNCs remains limited owing to the electrostatic attraction between cationic modifiers and electronegative CNCs. Herein, a cationized CNC (CNC-LA-IL) has been successfully prepared in aqueous media by grafting the [VBIm][BF4], a kind of ionic liquid (IL), on the surface of a sulfated CNC using lactic acid (LA) as a linker molecule. This surface functionalization not only converts the negative charge of CNC suspensions to a positive charge (zeta potential reversed from −35 to +40 mV) but also leads to enhanced thermal stability and redispersibility of the dried CNC. To examine the reinforcing effect of IL-modified CNCs, poly(vinyl alcohol) (PVA)/CNC-LA-IL nanocomposite films were further prepared by the solution casting method. To one’s surprise, the as-prepared PVA/CNC-LA-IL films exhibit extraordinary improvement in both the tensile strength (92%) and the toughness (166%) with only a 0.3 wt % CNC loading. This study provides a green and facile method to achieve ionic liquids grafted CNCs for high-performance nanocomposites.

Reactive 3D printed silanized cellulose nanofiber aerogels for solar-thermal regulatory cooling

Tianyi Zhu,Zeyu Ren,Debao Wang,Sudan Zhao,Xue Liu,Wei Fan,Yue-E Miao,Chao Zhang,Tianxi Liu

Polymer aerogels exhibit promise as solar-thermal co-management materials, offering combined thermal insulation and solar scattering characteristics. However, challenges persist in their large-scale preparation and pore structure tailoring. Herein, a polymethylsilsesquioxane interwoven cellulose nanofiber aerogel scaffold with improved interlayer interfaces and tunable pore sizes is prepared via reactive 3D printing. The resulting 3D-printed aerogel scaffold exhibits minimal volume shrinkage during freeze-drying and significantly enhanced interlayer interfaces, demonstrating superior fatigue resistance and impressive environmental resilience. The significantly decreased pore sizes in the aerogel scaffold greatly enhance full solar scattering through the Mie scattering mechanism. Utilized as a hydrophobic and flame-retardant solar–thermal regulatory cooler, the aerogel scaffold demonstrates a solar reflectance of 94.2 % and an atmospheric window emissivity of 95.6 %. The aerogel scaffold achieves a cooling power of 72.2 W m −2 with an average sub-ambient cooling of 5.8 °C under direct sunlight.

Reconstructed wood with high water stability from bark cellulose and corncob lignin

Guochen Xia,Shixu Yu,Zezhou Yang,Jingyi Lian,Yimin Xie,Qinghua Feng

Natural wood has been highly valued for thousands of years due to its excellent strength, low density, and ease of processing. However, its poor water stability, which leads to swelling and deformation, limits its competitiveness. In response, we designed a reconstructed wood through a process involving pretreatment, TEMPO oxidation, lignin self-assembly, lignin melting, and densification. In this material, cellulose serves as the skeleton, while lignin with a phenylpropyl structure acts as both a filler and binder. The resulting wood exhibits outstanding water stability, with no changes after 60 days of water immersion and a water absorption rate as low as 8.32 %. This stability is achieved through the densification of lignin, which is enhanced by lignin melting and pressure during self-assembly. The reconstructed wood not only offers excellent water stability but also boasts superior UV resistance and thermal stability. Additionally, it can be hot-pressed into straws within a mold, providing better water stability and tensile strength compared to paper straws. This reconstructed wood, made from natural wood and corncob, is biodegradable and environmentally friendly, offering a new approach to wood water stability strategies.