Articles de revues : « Nanocrystals composite material »

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Ramires, Elaine C., Jackson D. Megiatto, Alain Dufresne et Elisabete Frollini. « Cellulose Nanocrystals versus Microcrystalline Cellulose as Reinforcement of Lignopolyurethane Matrix ». Fibers 8, n^o 4 (29 mars 2020) : 21. http://dx.doi.org/10.3390/fib8040021.

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Cellulose nanocrystals (CNC) exhibit remarkable properties such as being lightweight, renewability, nanoscale dimension, raw material availability, and a unique morphology. They have been widely used in film-forming composites, but the literature is scarce concerning bulky-composites (i.e., non-filmogenic). Microcrystalline cellulose (MCC) is widely available and has emerged as an important material for the reinforcement of composites. This investigation focuses on the preparation of non-filmogenic composites prepared from a polyurethane-type matrix, based on modified lignosulfonate and castor oil, reinforced with CNC or MCC, aiming to compare their reinforcing capacity. CNC was obtained through the acid hydrolysis of MCC. Sodium lignosulfonate was chemically modified using glutaraldehyde to increase its reactivity towards isocyanate groups in the synthesis of lignopolyurethane. The results show that adding CNC or MCC led to materials with improved impact strength, flexural properties, and storage modulus compared to pristine lignopolyurethane. With the exception of the flexural modulus, which was higher for the CNC-reinforced composite compared to the MCC-reinforced composite, all other properties were similar. The set of results indicates that CNC and MCC are promising for the reinforcement of polyurethane-type matrices. Bulky materials with good properties and prepared from high renewable raw material contents were obtained, meeting current expectations concerning sustainable development.

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Wijaya, Christian J., Felycia E. Soetaredjo, Suryadi Ismadji et Setiyo Gunawan. « Synthesis of Cellulose Nanocrystals/HKUST-1 Composites and Their Applications : Crystal Violet Removal and Doxorubicin Loading ». Polymers 14, n^o 22 (18 novembre 2022) : 4991. http://dx.doi.org/10.3390/polym14224991.

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This study developed a novel composite material containing cellulose nanocrystals (CNCs) and HKUST-1. Here, the addition of CNCs was used to enhance the characteristics of HKUST-1 in terms of surface area, adsorption ability, and functional groups. Here, the fabrication of CNCs@HKUST-1 composites was carried out by adding CNCs into the fabrication process of HKUST-1. The addition of CNCs provides additional functional groups on the surface of composite material which can be used to attach other organic compounds, such as in waste management and drug delivery systems. Here, CNCs@HKUST-1 composites were tested as a material for crystal violet (CV) removal and doxorubicin (DOX) loading. The removal capacity of CNCs@HKUST-1 composite towards CV molecules reached 1182.25 ± 27.74 mg/g, while the loading capacity for DOX drugs was around 1514.94 ± 11.67 mg/g. Both applications showed that CNCs@HKUST-1 composite had higher adsorption capacity and ability compared to its precursor materials, i.e., CNCs and HKUST-1.

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Prokešová, Pavla, Nikolay Petkov, Jiří Čejka, Svetlana Mintova et Thomas Bein. « Micro/Mesoporous Composites Based on Colloidal Zeolite Grown in Mesoporous Matrix ». Collection of Czechoslovak Chemical Communications 70, n^o 11 (2005) : 1829–47. http://dx.doi.org/10.1135/cccc20051829.

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Composite materials containing micro- and mesopores are prepared under instantaneous hydrothermal treatment of initial solutions generally used for zeolite Beta and precursor solutions for mesoporous Al-MCM-41 material. The resulting composites are compared with pure, highly crystalline colloidal microporous Beta zeolite and hexagonally ordered mesostructured samples. The porosity and morphological features of the composite materials are influenced by the conditions of hydrothermal synthesis of the initial colloidal solutions used for the preparation of Beta seeds, as well as by the conditions of the synchronized crystallization of the final composites. The embedding of Beta seeds in the mesoporous silica matrix is possible via immediate heating of mesoporous precursor solutions with Beta seeds primarily formed. The composite materials contain either microcrystalline Beta nanodomains with sizes of about 5-10 nm surrounded by mesoporous material or defined Beta nanocrystals (20-40 nm), and at the same time connected with mesostructured material. The presence of highly crosslinked silicate framework walls and tetrahedrally coordinated aluminum in the composite material are confirmed by solid-state 29Si and 27Al MAS NMR spectroscopy. The concentration of Brønsted acid sites in the micro/mesoporous composites is increased substantially in comparison with pure mesoporous Al-MCM-41 material proven by FTIR acetonitrile-d3 adsorption study.

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Craievich, A. F., O. L. Alves et L. C. Barbosa. « Formation and Growth of Semiconductor PbTe Nanocrystals in a Borosilicate Glass Matrix ». Journal of Applied Crystallography 30, n^o 5 (1 octobre 1997) : 623–27. http://dx.doi.org/10.1107/s0021889897001799.

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Pb- and Te-doped borosilicate glasses are transformed by appropriate heat treatment into a composite material consisting of a vitreous matrix in which semiconductor PbTe nanocrystals are embedded. This composite exhibits interesting non-linear optical properties in the infrared region, in the range 10–20 000 Å. The shape and size distribution of the nanocrystals and the kinetics of their growth were studied by small-angle X-ray scattering (SAXS) during in situ isothermal treatment at 923 K. The experimental results indicate that nanocrystals are nearly spherical and have an average radius increasing from 16 to 33 Å after 2 h at 923 K, the relative size dispersion being time-invariant and approximately equal to 8%. This investigation demonstrates that the kinetics of nanocrystal growth are governed by the classic mechanism of atomic diffusion. The radius of nanocrystals, deduced by applying the simple Efros & Efros [Sov. Phys. Semicond. (1982), 16, 772–775] model using the energy values corresponding to the exciton peaks of optical absorption spectra, does not agree with the average radius determined by SAXS.

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Zhu, Chunxia, Shuyu Pang, Zhaoxia Chen, Lehua Bi, Shuangfei Wang, Chen Liang et Chengrong Qin. « Synthesis of Covalent Organic Frameworks (COFs)-Nanocellulose Composite and Its Thermal Degradation Studied by TGA/FTIR ». Polymers 14, n^o 15 (2 août 2022) : 3158. http://dx.doi.org/10.3390/polym14153158.

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At present, the synthesis methods of crystalline porous materials often involve powder products, which not only affects the practical application but also has complex synthesis operations and limited scale. Based on the mechanochemical method, we choose COF-TpPa-1, preparing TpPa-1-DANC composites. Covalent organic frameworks (COFs) are a kind of crystalline material formed by covalent bonds of light elements. COFs possess well pore structure and high thermal stability. However, the state of synthesized powders limits their application. Cellulose nanocrystals (CNCs) are promising renewable micron materials with abundant hydroxyl groups on their surface. It is possible to prepare high-strength materials such as film, water, and aerogel. Firstly, the nanocellulose was oxidized by the sodium periodate method to obtain aldehyde cellulose nanocrystals (DANC). TpPa-1-DANC not only had the crystal characteristic peak of COFs at 2θ ≈ 5° but also had a BET surface area of 247 m2/g. The chemical bonds between COFs and DANC formed by Schiff base reaction appeared in FTIR and XPS. The pyrolysis behavior of the composite was characterized by TG-IR, which showed that the composite had good thermal stability. With the advantages of nanocellulose as a material in every dimension, we believe that this method can be conducive to the large-scale synthesis of COFs composites, and has the possibility of multi-form synthesis of COFs.

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Cherevkov, Sergei, Ruslan Azizov, Anastasiia Sokolova, Valeriia Nautran, Mikhail Miruschenko, Irina Arefina, Mikhail Baranov et al. « Interface Chemical Modification between All-Inorganic Perovskite Nanocrystals and Porous Silica Microspheres for Composite Materials with Improved Emission ». Nanomaterials 11, n^o 1 (7 janvier 2021) : 119. http://dx.doi.org/10.3390/nano11010119.

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In recent years, there has been rapid progress in the development of photonic devices based on lead halide perovskite nanocrystals since they possess a set of unique optical and charge transport properties. However, the main limiting factor for their subsequent application is poor stability against exposure to adverse environmental conditions. In this work, a study of a composite material based on perovskite CsPbBr3 nanocrystals embedded in porous silica microspheres is presented. We developed two different approaches to change the interface between nanocrystals and the surface of the microsphere pores: surface treatment of (i) nanocrystals or (ii) microspheres. The surface modification with tetraethylorthosilicate molecules not only increased stability but also improved the optical responses of the composite material. The position of the emission band remained almost unchanged, but its lifetime increased significantly compared to the initial value. The improvement of the optical performance via surface modification with tetraethylorthosilicate molecules also works for the lead-free Bi-doped Cs2AgInCl6 double perovskite nanocrystals leading to increased stability of their optical responses at ambient conditions. These results clearly demonstrate the advantage of a composite material that can be used in novel photonic devices with improved performance.

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Petrella, A., M. Tamborra, P. D. Cozzoli, M. L. Curri, M. Striccoli, P. Cosma, G. M. Farinola, F. Babudri, F. Naso et A. Agostiano. « TiO2 nanocrystals – MEH-PPV composite thin films as photoactive material ». Thin Solid Films 451-452 (mars 2004) : 64–68. http://dx.doi.org/10.1016/j.tsf.2003.10.106.

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Huo, Ying, Yingying Liu, Mingfeng Xia, Hong Du, Zhaoyun Lin, Bin Li et Hongbin Liu. « Nanocellulose-Based Composite Materials Used in Drug Delivery Systems ». Polymers 14, n^o 13 (29 juin 2022) : 2648. http://dx.doi.org/10.3390/polym14132648.

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Nanocellulose has lately emerged as one of the most promising “green” materials due to its unique properties. Nanocellulose can be mainly divided into three types, i.e., cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial cellulose (BC). With the rapid development of technology, nanocellulose has been designed into multidimensional structures, including 1D (nanofibers, microparticles), 2D (films), and 3D (hydrogels, aerogels) materials. Due to its adaptable surface chemistry, high surface area, biocompatibility, and biodegradability, nanocellulose-based composite materials can be further transformed as drug delivery carriers. Herein, nanocellulose-based composite material used for drug delivery was reviewed. The typical drug release behaviors and the drug release mechanisms of nanocellulose-based composite materials were further summarized, and the potential application of nanocellulose-based composite materials was prospected as well.

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Liu, Sichen, Yanbo Yu, Kelu Ni, Tongda Liu, Min Gu, Yingchen Wu, Guanben Du et Xin Ran. « Construction of a novel electrochemical sensor based on biomass material nanocellulose and its detection of acetaminophen ». RSC Advances 12, n^o 43 (2022) : 27736–45. http://dx.doi.org/10.1039/d2ra04125a.

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Ozola, Zanda U., Rudite Vesere, Silvija N. Kalnins et Dagnija Blumberga. « Paper Waste Recycling. Circular Economy Aspects ». Environmental and Climate Technologies 23, n^o 3 (1 décembre 2019) : 260–73. http://dx.doi.org/10.2478/rtuect-2019-0094.

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Abstract Paper waste is a raw material for a lot of products with different added value. The engineering, economic and environmental aspects of paper waste recycling are analysed for production of composite material, cellulose nanofibers and nanocrystals, bricks with paper components, porous carbon, film of biopolymer, enzymatic sugar and bioenergy: bioethanol, hydrogen and biofuel. Through multicriteria analysis, it was possible to determine the most feasible paper waste recycling product in case of four product groups: egg packaging boxes, cardboard, reused paper, cellulose nanomaterials (nanofibers and nanocrystals). The production of cellulose nanofibres and cellulose nanocrystals has an advantage over egg packaging and cardboard production as well as reusable paper.

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Zhang, Zeju, Mang Niu, Wei Li, Chenfeng Ding, Peitao Xie, Yongxin Li, Lili Chen et al. « Steered polymorphic nanodomains in TiO₂ to boost visible-light photocatalytic oxidation ». RSC Advances 12, n^o 16 (2022) : 9660–70. http://dx.doi.org/10.1039/d2ra00782g.

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Zhang, Yandi, Xiaoquan Chen et Wenhao Shen. « Preparation and characterization of high-purity cellulose nanocrystals films by the composite enzymolysis of cotton pulp fibers ». BioResources 18, n^o 1 (8 novembre 2022) : 247–54. http://dx.doi.org/10.15376/biores.18.1.247-254.

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Using cotton pulp fibers as raw material, through composite enzymolysis and purification, two different forms of high-purity cellulose nanocrystals were obtained, namely spherical CNCs (SCNCs) and rod-like CNCs (RCNCs). Vacuum filtration was used to obtain pure SCNCs film and pure RCNCs film. The films were characterized by scanning electron microscopy, ultraviolet–visible spectrometry, and X-ray diffraction and tested for their mechanical properties. The films were shown to have good light transmittance and softness, and the structures were unchanged compared with the cellulose raw materials. This article mainly introduces the preparation process of high-purity cellulose nanocrystals films and provides data support for subsequent research.

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Khili, Faouzia, et Amel Dakhlaoui Omrani. « Synthesis of nanocellulose/cobalt oxide composite for efficient degradation of Rhodamine B by activation of peroxymonosulfate ». European Journal of Chemistry 10, n^o 1 (31 mars 2019) : 19–25. http://dx.doi.org/10.5155/eurjchem.10.1.19-25.1789.

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In recent years, nanofibrous materials derived from biopolymers have attracted more interest due to their numerous applications. In our study, a simple composite of cellulose nanocrystals, and cobalt oxide nanoparticles was elaborated using sodium borohydride as a chemical reducer. It has been shown that Co3O4 nanoparticles were grown on the surface of cellulose nanocrystals. An important quantity of cobalt oxide nanoparticles was detected using ICP-OES (13.5 g contained in 100 mg of the composite). The size, the morphology and the thermal stability of the composite and the obtained nanoparticles were studied using X-ray powder diffraction, Fourier-transform infrared spectroscopy, Ultraviolet-Visible spectrophotometry, Scanning electron microscopic and Transmission electron microscopic. Our obtained material was used for the degradation of Rhodamine B and it was succeeded in degradation of Rhodamine B within very short period of time (16 min). The catalytic degradation of Rhodamine B was investigated and analyzed with UV-Visible absorption spectra.

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Wang, Lili, Cong Guo, Yongchun Zhu, Jianbin Zhou, Long Fan et Yitai Qian. « A FeCl2-graphite sandwich composite with Cl doping in graphite layers : a new anode material for high-performance Li-ion batteries ». Nanoscale 6, n^o 23 (2014) : 14174–79. http://dx.doi.org/10.1039/c4nr05070c.

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Choi, YongJae, et John Simonsen. « Cellulose Nanocrystal-Filled Carboxymethyl Cellulose Nanocomposites ». Journal of Nanoscience and Nanotechnology 6, n^o 3 (1 mars 2006) : 633–39. http://dx.doi.org/10.1166/jnn.2006.132.

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Polymer nanocomposites are one of the important application areas for nanotechnology. Naturally derived organic nanophase materials are of special interest in the case of polymer nanocomposites. Carboxymethyl cellulose is a polyelectrolyte derived from natural materials. It has been extensively studied as a hydrogel polymer. Methods to modify the mechanical properties of gels and films made from CMC are of interest in our lab and in the commercial marketplace. The effect of nano-sized fillers on the properties of CMC-based composites is of interest in the development of novel or improved applications for hydrogel polymers in general and CMC in particular. This project investigated cellulose nanocrystals (CNXLs) as a filler in CMC and compared the effects to microcrystalline cellulose (MCC). The composite material was composed of CMC, MCC or CNXL, with glycerin as a plasticizer. CNXL and MCC concentrations ranged from 5% to 30%. Glycerin concentrations were kept constant at 10%. CNXLs improved the strength and stiffness of the resulting composite compared to MCC. In addition, a simple heat treatment was found to render the nanocomposite water resistant.

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Havryliuk, Yevhenii, Volodymyr Dzhagan, Anatolii Karnaukhov, Oleksandr Selyshchev, Julia Hann et Dietrich R. T. Zahn. « Raman Spectroscopy and Thermoelectric Characterization of Composite Thin Films of Cu2ZnSnS4 Nanocrystals Embedded in a Conductive Polymer PEDOT:PSS ». Nanomaterials 13, n^o 1 (22 décembre 2022) : 41. http://dx.doi.org/10.3390/nano13010041.

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Cu2ZnSnS4 (CZTS) is an intensively studied potential solar cell absorber and a promising thermoelectric (TE) material. In the form of colloidal nanocrystals (NCs), it is very convenient to form thin films on various substrates. Here, we investigate composites of CZTS NCs with PEDOT:PSS, a widely used photovoltaics polymer. We focus on the investigation of the structural stability of both NCs and polymers in composite thin films with different NC-to-polymer ratios. We studied both pristine films and those subjected to flash lamp annealing (FLA) or laser irradiation with various power densities. Raman spectroscopy was used as the main characterization technique because the vibrational modes of CZTS NCs and the polymer can be acquired in one spectrum and thus allow the properties of both parts of the composite to be monitored simultaneously. We found that CZTS NCs and PEDOT:PSS mutually influence each other in the composite. The thermoelectric properties of PEDOT:PSS/CZTS composite films were found to be higher compared to the films consisting of bare materials, and they can be further improved by adding DMSO. However, the presence of NCs in the polymer deteriorates its structural stability when subjected to FLA or laser treatment.

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Thompson, Lachlan, Jalal Azadmanjiri, Mostafa Nikzad, Igor Sbarski, James Wang et Aimin Yu. « Cellulose Nanocrystals : Production, Functionalization and Advanced Applications ». REVIEWS ON ADVANCED MATERIALS SCIENCE 58, n^o 1 (1 avril 2019) : 1–16. http://dx.doi.org/10.1515/rams-2019-0001.

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Abstract Cellulose nanocrystals (CNC) are a class of nanoscale biopolymers produced from cellulose sources. CNC materials have gained growing interests which can be attributed to their excellent properties such as excellent biocompatibility, good mechanical properties and high aspect ratio whilst also being an inexpensive material that can be produced from green and renewable sources. Due to the abundant hydroxyl functional groups, the surface of CNC materials are ready to be tuned and functionalized via chemical reactions allowing for many different applications, such as being a reinforcing agent to be incorporated into a hydrophobic polymer matrix. In this review paper,we firstly introduce the general methods for producing CNC from different sources. Different strategies used for surface modification ofCNCare then discussed. Finally, the recent progress on the applications of CNC and CNC composite materials are described in detail.

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Děcká, Kateřina, Jan Král, František Hájek, Petr Průša, Vladimir Babin, Eva Mihóková et Václav Čuba. « Scintillation Response Enhancement in Nanocrystalline Lead Halide Perovskite Thin Films on Scintillating Wafers ». Nanomaterials 12, n^o 1 (21 décembre 2021) : 14. http://dx.doi.org/10.3390/nano12010014.

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Lead halide perovskite nanocrystals of the formula CsPbBr3 have recently been identified as potential time taggers in scintillating heterostructures for time-of-flight positron emission tomography (TOF-PET) imaging thanks to their ultrafast decay kinetics. This study investigates the potential of this material experimentally. We fabricated CsPbBr3 thin films on scintillating GGAG:Ce (Gd2.985Ce0.015Ga2.7Al2.3O12) wafer as a model structure for the future sampling detector geometry. We focused this study on the radioluminescence (RL) response of this composite material. We compare the results of two spin-coating methods, namely the static and the dynamic process, for the thin film preparation. We demonstrated enhanced RL intensity of both CsPbBr3 and GGAG:Ce scintillating constituents of a composite material. This synergic effect arises in both the RL spectra and decays, including decays in the short time window (50 ns). Consequently, this study confirms the applicability of CsPbBr3 nanocrystals as efficient time taggers for ultrafast timing applications, such as TOF-PET.

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Nakashima, Kouichi, Ichiro Fujii et Satoshi Wada. « Preparation of BaZrO₃ Nanocrystals at Low Temperature ». Key Engineering Materials 582 (septembre 2013) : 165–68. http://dx.doi.org/10.4028/www.scientific.net/kem.582.165.

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Barium zirconate (BaZrO3) was prepared by the composite-hydroxide-mediated (CHM) approach at low temperature. The CHM method is based on chemical reactions of materials in the eutectic hydroxide melt. In this method, the eutectic point at an sodium hydroxide (NaOH) : potassium hydroxide (KOH) molar ratio of 51.5 : 48.5 is about 165°C. In the present work, the low-temperature preparation and morphology of BaZrO3 nanocrystals were investigated. Zirconium tetra-n-butoxide ((CH3CH2CH2CH2O)4Zr) and/or zirconium dioxide (ZrO2) were used as a zirconium source. X-ray diffraction measurements confirmed that the BaZrO3 had a perovskite structure. Barium hydroxide (Ba (OH)2) was used as a barium source. BaZrO3 nanoparticles were obtained when (CH3CH2CH2CH2O)4Zr was used as a raw material. On the other hand, BaZrO3 nanocubes were formed when ZrO2 was used as a raw material. Scanning electron microscopy and transmission electron microscopy observations indicated that BaZrO3 nanocrystals were formed.

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Zhao, Chen, Zhi Yu, Jun Xing, Yuting Zou, Huiwen Liu, Hao Zhang, Weili Yu, Hicham Idriss et Chunlei Guo. « Effect of Ag2S Nanocrystals/Reduced Graphene Oxide Interface on Hydrogen Evolution Reaction ». Catalysts 10, n^o 9 (19 août 2020) : 948. http://dx.doi.org/10.3390/catal10090948.

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The development of efficient electrocatalyst to produce molecular hydrogen from water is receiving considerable attention, in an effort to decrease our reliance on fossil fuels. The prevention of the aggregation of active sites during material synthesis, in order to increase charge transport properties of electrocatalysts, is needed. We have designed, synthesized, and studied a Ag2S/reduced graphene oxide (rGO) electrochemical catalyst (for hydrogen evolution) from water. The Ag2S nanocrystals were synthesized by the solvothermal method in which the rGO was added. The addition of the rGO resulted in the formation of smaller Ag2S nanocrystals, which consequently increased the electrical conductivity of the composite catalyst. The composite catalyst showed a higher electrochemical catalytic activity than the one with an absence of rGO. At a current density of 10 mA/cm2, a low overpotential of 120 mV was obtained. A Tafel slope of 49.1 mV/dec suggests a Volmer–Herovsky mechanism for the composite catalyst. These results may provide a novel strategy for developing hydrogen evolution reaction (HER) electrocatalysts, via the combining of a nano-semiconductor catalyst with a 2D material.

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Su, Si, Shaoying Hu et Qi Liu. « Application of Polypyrrole Cellulose Nanocrystalline Composite Conductive Material in Garment Design ». Advances in Materials Science and Engineering 2022 (21 septembre 2022) : 1–11. http://dx.doi.org/10.1155/2022/4187826.

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The Chinese nation has a long cultural history and has deep attainments in food, clothing, art, and other cultural fields. With the development of science, technology, economy, and culture, new materials continue to appear, providing new ideas for clothing design. Polypyrrole is a common conductive polymer. The pure pyrrole monomer presents a colorless oily liquid at room temperature, slightly soluble in water and nontoxic. Nanocrystals, also called nanoscale crystals, use high-energy polymer spheres to pack calcium, magnesium ions, and bicarbonate in water to produce a water-insoluble crystal structure. Conductive composite materials mainly refer to composite conductive polymer materials, which are composed of polymers and various conductive substances through a certain composite method. This article aims to study the application of polypyrrole cellulose nanocrystalline composite conductive material in clothing design. Starting from the structural characteristics of the polypyrrole cellulose nanocrystalline composite conductive material, this article uses case analysis to study deeply the suitable polypyrrole cellulose nanocrystalline composite conductive material. This article can effectively use the innovative application method of its appearance style, so as to realize its application in clothing design. Starting from the functional properties of the polypyrrole cellulose nanocrystalline composite conductive material, the specific application of the polypyrrole cellulose nanocrystalline composite conductive material in different clothing designs is analyzed. Combining the postmodernist clothing style characteristics, aesthetic habits, and the characteristics of polypyrrole cellulose nanocrystalline composite conductive materials, this paper studies the innovative style design of polypyrrole cellulose nanocrystalline composite conductive materials. The experimental results in this paper show that when the reaction time is 2 min, the reaction rate at this time is zero, indicating that this time is in the initial stage of the reaction. After 4 minutes, as the reaction time increases, the reaction rate shows an increasing trend; when the reaction time is longer than 10 minutes, the reaction rate increases slowly and has a downward trend, which indicates the end of the reaction. The highest average reaction rate is about 7.5 mg/min.

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Kubus, Mariusz, Andrzej M. Kłonkowski, Andriy Lotnyk et Lorenz Kienle. « Luminescence enhancement in composite material : CaWO4:Tb3+ nanocrystals incorporated into silica xerogel ». Materials Chemistry and Physics 149-150 (janvier 2015) : 424–29. http://dx.doi.org/10.1016/j.matchemphys.2014.10.040.

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Hu, YaJie, YaShuai Niu, GenQue Fu, PanPan Yue, MingFei Li, Feng Peng et RunCang Sun. « Turning Wood Autohydrolysate Directly into Food Packing Composite Films with Good Toughness ». International Journal of Polymer Science 2018 (25 mars 2018) : 1–8. http://dx.doi.org/10.1155/2018/2097340.

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Bio-based composite films were produced by incorporating wood autohydrolysate (WH), chitosan (CS), and cellulose nanocrystals (CNC). In this work, WH was directly utilized without further purification, and CNC was introduced as the reinforced material to prepare WH-CS-CNC composite films with excellent properties. The effects of CNC on the properties of WH-CS-CNC composite films were investigated by characterizing their structures, mechanical properties, oxygen barrier, and thermal stability properties. The results suggested that CNC could improve tensile strength of the composite films, and the tensile strain at break could be up to 4.7%. Besides, the oxygen permeability of the prepared composite films could be as low as 3.57 cm3/day·m2·kPa, making them suitable for the food packaging materials. These above results showed that the addition of CNC is an effective method to enhance the toughness of composite films. In addition, WH-CS-CNC composite films have great potential in the field of sustainable food packing materials.

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Jiang, Yong, Min Wei, Jinkui Feng, Yuchen Ma et Shenglin Xiong. « Enhancing the cycling stability of Na-ion batteries by bonding SnS2ultrafine nanocrystals on amino-functionalized graphene hybrid nanosheets ». Energy & ; Environmental Science 9, n^o 4 (2016) : 1430–38. http://dx.doi.org/10.1039/c5ee03262h.

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An integrated composite tin sulfide bonded on an amino-functionalized graphene as a novel anode material for NIBs is reported. Tight contact with SnS₂nanocrystals and discharge products on the amino-functionalized graphene interface results in excellent electrochemical performance.

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Enikeeva, Violetta A., Ilya A. Ozheredov, Aleksandr P. Shkurinov, V. Ya Gayvoronsky et I. M. Pritula. « Dielectric Properties of Copmosite Material Single Crystal KDP Matrix with Incorporated Anatase Nanocrystals in Terahertz Spectral Region ». Siberian Journal of Physics 5, n^o 4 (1 décembre 2010) : 134–39. http://dx.doi.org/10.54362/1818-7919-2010-5-4-134-139.

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Dielectric properties of new composite material single crystal KDP matrix with incorporated anatase nanocrystals were investigated by terahertz time-domain spectroscopy in a wide temperature range. It was shown that anatase nanoparticles significantly effect on dielectric properties of KDP crystals in THz range. It was obtained that dielectric permittivity drastically changes at the temperature below phase transition

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Slouf, Miroslav, Radim Skoupy, Ewa Pavlova et Vladislav Krzyzanek. « Powder Nano-Beam Diffraction in Scanning Electron Microscope : Fast and Simple Method for Analysis of Nanoparticle Crystal Structure ». Nanomaterials 11, n^o 4 (9 avril 2021) : 962. http://dx.doi.org/10.3390/nano11040962.

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We introduce a novel scanning electron microscopy (SEM) method which yields powder electron diffraction patterns. The only requirement is that the SEM microscope must be equipped with a pixelated detector of transmitted electrons. The pixelated detectors for SEM have been commercialized recently. They can be used routinely to collect a high number of electron diffraction patterns from individual nanocrystals and/or locations (this is called four-dimensional scanning transmission electron microscopy (4D-STEM), as we obtain two-dimensional (2D) information for each pixel of the 2D scanning array). Nevertheless, the individual 4D-STEM diffractograms are difficult to analyze due to the random orientation of nanocrystalline material. In our method, all individual diffractograms (showing randomly oriented diffraction spots from a few nanocrystals) are combined into one composite diffraction pattern (showing diffraction rings typical of polycrystalline/powder materials). The final powder diffraction pattern can be analyzed by means of standard programs for TEM/SAED (Selected-Area Electron Diffraction). We called our new method 4D-STEM/PNBD (Powder NanoBeam Diffraction) and applied it to three different systems: Au nano-islands (well diffracting nanocrystals with size ~20 nm), small TbF3 nanocrystals (size < 5 nm), and large NaYF4 nanocrystals (size > 100 nm). In all three cases, the STEM/PNBD results were comparable to those obtained from TEM/SAED. Therefore, the 4D-STEM/PNBD method enables fast and simple analysis of nanocrystalline materials, which opens quite new possibilities in the field of SEM.

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Rasheed, Masrat, Mohammad Jawaid et Bisma Parveez. « Bamboo Fiber Based Cellulose Nanocrystals/Poly(Lactic Acid)/Poly(Butylene Succinate) Nanocomposites : Morphological, Mechanical and Thermal Properties ». Polymers 13, n^o 7 (29 mars 2021) : 1076. http://dx.doi.org/10.3390/polym13071076.

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The purpose of this work was to investigate the effect of cellulose nanocrystals (CNC) from bamboo fiber on the properties of poly (lactic acid) (PLA)/poly (butylene succinate) (PBS) composites fabricated by melt mixing at 175 °C and then hot pressing at 180 °C. PBS and CNC (0.5, 0.75, 1, 1.5 wt.%) were added to improvise the properties of PLA. The morphological, physiochemical and crystallinity properties of nanocomposites were analysed by field emission scanning electron microscope (FESEM), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD), respectively. The thermal and tensile properties were analysed by thermogravimetic analysis (TGA), Differential scanning calorimetry (DSC) and Universal testing machine (UTM). PLA-PBS blend shows homogeneous morphology while the composite shows rod-like CNC particles, which are embedded in the polymer matrix. The uniform distribution of CNC particles in the nanocomposites improves their thermal stability, tensile strength and tensile modulus up to 1 wt.%; however, their elongation at break decreases. Thus, CNC addition in PLA-PBS matrix improves structural and thermal properties of the composite. The composite, thus developed, using CNC (a natural fiber) and PLA-PBS (biodegradable polymers) could be of immense importance as they could allow complete degradation in soil, making it a potential alternative material to existing packaging materials in the market that could be environment friendly.

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Belesi, M., I. Panagiotopoulos, S. Pal, S. Hariharan, D. Tsitrouli, G. Papavassiliou, D. Niarchos, N. Boukos, M. Fardis et V. Tzitzios. « Decoration of Carbon Nanotubes with CoO and Co Nanoparticles ». Journal of Nanomaterials 2011 (2011) : 1–9. http://dx.doi.org/10.1155/2011/320516.

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Multiwall carbon nanotubes (MWNTs) decorated with CoO nanocrystals were synthesized by in-situ thermal decomposition of Co(acac)2 in oleyl amine under reflux conditions open in the air. The CoO/MWNTs composite material can be easily converted to metallic Co/MWNTs through annealing under reducing atmosphere (4% H2) at 500°C without any significant sintering effect. The composite materials characterized by X-ray diffraction, transmission electron microscopy, and Nuclear Magnetic Resonance (NMR) spectroscopy. The structural and morphological characterization shows that the CoO has cubic face (fcc) and the particles deposited uniformly on the external surface of the carbon nanotubes. In the annealed materials, the NMR shows that the fcc and hcp metallic Co phases coexist with a significant percentage of stacking faults. The magnetic measurements indicated that the CoO/MWNTs composite is largely composed of CoO nanoparticles with uncompensated surface spins. The fluctuations of spins persist in partially reduced CoO grains as shown by nuclear spin-lattice relaxation measurements.

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Khodosova, Nataliya, Lyudmila Novikova, Elena Tomina, Larisa Belchinskaya, Alexander Zhabin, Nikolay Kurkin, Victoria Krupskaya et al. « Magnetic Nanosorbents Based on Bentonite and CoFe2O4 Spinel ». Minerals 12, n^o 11 (21 novembre 2022) : 1474. http://dx.doi.org/10.3390/min12111474.

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New magnetic nanocomposite sorbents were obtained by doping natural bentonite with nanosized CoFe2O4 spinel (10 and 20 wt.%). Nanocrystals of cobalt ferrite were synthesized by a citrate burning method. The structure and physical-chemical properties of the composites were characterized by XRD, XRF, TEM, BET, FTIR and Faraday balance magnetometry. During the formation of nanocomposites, 10–30 nm particles of cobalt ferrite occupied mainly the interparticle space of Fe-aluminosilicate that significantly changed the particle morphology and composite porosity, but at the same time retained the structure of the 2:1 smectite layer. A combination of two functional properties of composites, adsorption and magnetism has been found. The adsorption capacity of magnetic nanosorbents exceeded this parameter for bentonite and spinel. Despite the decrease in the adsorption volume, pore size and specific surface area of the composite material relative to bentonite, the sorption activity of the composite increases by 12%, which indicated the influence of the magnetic component on the sorption process. FTIR data confirmed the mechanism of formaldehyde sorption by the composite sorbent. The production of a magnetic nanosorbent opens up new possibilities for controlling the sorption processes and makes it possible to selectively separate the sorbent from the adsorption medium by the action of a magnetic field.

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Niu, Lin, Rui Zou, Qida Liu, Quanli Li, Xinmin Chen et Zhiqing Chen. « A Novel Nanocomposite Particle of Hydroxyapatite and Silk Fibroin : Biomimetic Synthesis and Its Biocompatibility ». Journal of Nanomaterials 2010 (2010) : 1–7. http://dx.doi.org/10.1155/2010/729457.

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A novel bone-like biomaterial of hydroxyapatite (HAP) and silk fibroin (SF) composite was developed by biomimetic synthesis. The composite was precipitated from drops of Ca(OH)2suspension andH3PO4solution with SF. With this method, the HAP nanocrystals were obtained by self-assembling on a SF surface whose c-axis was aligned with the long-axis direction of SF in microstructures; this shares the same misconstrues of collagen and HAP with that in the natural bone. The HAP/SF composite then demonstrated that it could promote osteoblast proliferationin vitroand new bone formationin vivo. The novel biomaterial is a promising material for bone replacement and regeneration.

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Szkudlarek, Aleksandra, Alfredo Rodrigues Vaz, Yucheng Zhang, Andrzej Rudkowski, Czesław Kapusta, Rolf Erni, Stanislav Moshkalev et Ivo Utke. « Formation of pure Cu nanocrystals upon post-growth annealing of Cu–C material obtained from focused electron beam induced deposition : comparison of different methods ». Beilstein Journal of Nanotechnology 6 (13 juillet 2015) : 1508–17. http://dx.doi.org/10.3762/bjnano.6.156.

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In this paper we study in detail the post-growth annealing of a copper-containing material deposited with focused electron beam induced deposition (FEBID). The organometallic precursor Cu(II)(hfac)2 was used for deposition and the results were compared to that of compared to earlier experiments with (hfac)Cu(I)(VTMS) and (hfac)Cu(I)(DMB). Transmission electron microscopy revealed the deposition of amorphous material from Cu(II)(hfac)2. In contrast, as-deposited material from (hfac)Cu(I)(VTMS) and (hfac)Cu(I)(DMB) was nano-composite with Cu nanocrystals dispersed in a carbonaceous matrix. After annealing at around 150–200 °C all deposits showed the formation of pure Cu nanocrystals at the outer surface of the initial deposit due to the migration of Cu atoms from the carbonaceous matrix containing the elements carbon, oxygen, and fluorine. Post-irradiation of deposits with 200 keV electrons in a transmission electron microscope favored the formation of Cu nanocrystals within the carbonaceous matrix of freestanding rods and suppressed the formation on their surface. Electrical four-point measurements on FEBID lines from Cu(hfac)2 showed five orders of magnitude improvement in conductivity when being annealed conventionally and by laser-induced heating in the scanning electron microscope chamber.

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Kim, Young-Seong, Jin Woo Baek, Zhengyun Jin, Hee Chang Jeon, Min-Woo Han et Joong Yeon Lim. « Mechanical Properties of a Bone-like Bioceramic–Epoxy-Based Composite Material with Nanocellulose Fibers ». Materials 16, n^o 2 (12 janvier 2023) : 739. http://dx.doi.org/10.3390/ma16020739.

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Several composite materials are being investigated as reinforcement fillers for surgery simulations. This study presents an artificial composite material with properties similar to those of the human bone, which may be used in surgery simulations. Moreover, considering the potential toxicity of debris generated during sawing, a safe epoxy-based composite material was synthesized using cellulose nanocrystals (CNCs) and bioceramics (i.e., hydroxyapatite, Yttria stabilized zirconia oxide, Zirconia oxide), which were used to mimic the stiffness of human bone. To examine the change in mechanical properties according to the composition, 1, 3, and 5 wt% of CNCs were mixed with 5 wt% of the bioceramics. When CNCs were added at 1 wt%, there was a confirmed change in the non-linear stiffness and ductility. The CNC-added specimen fractured when forming a nano-network around the local CNCs during curing. In contrast, the specimen without CNCs was more densely structured, and combined to form a network of all specimens such that a plastic region could exist. Thus, this study successfully manufactured a material that could mimic longitudinal and transverse characteristics similar to those of real human bone, as well as exhibit mechanical properties such as strength and stiffness. Bioceramics are harmless to the human body, and can be used by controlling the added quantity of CNCs. We expect that this material will be suitable for use in surgery simulations.

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Tang, Jingjing, Juan Yang, Limin Zhou, Jing Xie, Guanghui Chen et Xiangyang Zhou. « Layer-by-layer self-assembly of a sandwich-like graphene wrapped SnOx@graphene composite as an anode material for lithium ion batteries ». J. Mater. Chem. A 2, n^o 18 (2014) : 6292–95. http://dx.doi.org/10.1039/c4ta00495g.

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Scano, Alessandra, Valentina Cabras et Guido Ennas. « A New One-Pot Way to Prepare Enzyme-Containing Coordination Polymers by Sonochemistry ». Journal of Nanoscience and Nanotechnology 21, n^o 5 (1 mai 2021) : 2935–38. http://dx.doi.org/10.1166/jnn.2021.19042.

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Enzyme-containing Coordination Polymers (CPs) were prepared by a one-pot sonochemical method, mixing Glucose Oxidase (GOx) enzyme, 4,4′-bipyridine as spacer ligand, and chloride zinc salt. The reaction took place in a very short time (a few minutes) with a minimum use of solvents compared to conventional methods. The obtained composite material, named GOx-[Zn(4,4′-bipy)Cl2]∞, resulted from embedding the GOx molecules into uniformly sized [Zn(4,4′-bipy)Cl2] nanocrystals. The structural and thermal characterization, confirmed that the adopted strategy allows the preparation of hybrid bio-nanomaterials in a very fast, facile and eco-friendly method, by simply synthesising the [Zn(4,4′-bipy)Cl2] nanocrystals in the presence of the enzyme.

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Chou, Chun-Tu, Shih-Chen Shi et Chih-Kuang Chen. « Sandwich-Structured, Hydrophobic, Nanocellulose-Reinforced Polyvinyl Alcohol as an Alternative Straw Material ». Polymers 13, n^o 24 (18 décembre 2021) : 4447. http://dx.doi.org/10.3390/polym13244447.

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An environmentally friendly, hydrophobic polyvinyl alcohol (PVA) film was developed as an alternative to commercial straws for mitigating the issue of plastic waste. Nontoxic and biodegradable cellulose nanocrystals (CNCs) and nanofibers (CNFs) were used to prepare PVA nanocomposite films by blade coating and solution casting. Double-sided solution casting of polyethylene-glycol–poly(lactic acid) (PEG–PLA) + neat PLA hydrophobic films was performed, which was followed by heat treatment at different temperatures and durations to hydrophobize the PVA composite films. The hydrophobic characteristics of the prepared composite films and a commercial straw were compared. The PVA nanocomposite films exhibited enhanced water vapor barrier and thermal properties owing to the hydrogen bonds and van der Waals forces between the substrate and the fillers. In the sandwich-structured PVA-based hydrophobic composite films, the crystallinity of PLA was increased by adjusting the temperature and duration of heat treatment, which significantly improved their contact angle and water vapor barrier. Finally, the initial contact angle and contact duration (at the contact angle of 20°) increased by 35% and 40%, respectively, which was a significant increase in the service life of the biodegradable material-based straw.

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Li, Quan Li, Nan Huang, Zhi Qing Chen et Xu Yan Tang. « Biomimetic Synthesis of the Nanocomposite of Phosphorylatd Chitosan and Hydroxyapatite and its Bioactivity In Vitro ». Key Engineering Materials 330-332 (février 2007) : 721–24. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.721.

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Phosphorylated chitosan (PCS) was used as the template to control hydroxyapatite(HAp) growth, a novel nanocomposite composed of PCS and HAp was synthesized by biomimetic method. Calcium phosphate (Ca 2+= 60mM, Ca/P = 1.67) solution in HCl was added dropwise into PCS solution in NaOH. The precipitate was lyophilized to obtain the composite. The biocompatibility of the PCS-HAp nanocomopite was evaluated by osteoblast culture in vitro. The results showed that low crystallized HAp nanocrystals was formed on the PCS fibers and its crystallographic c-axis were aligned preferentially parallel to the long axis direction of PCS; the composite have good biocompatibility in vitro. It is expected that the novel composite to be a potential material for bone repair.

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Fahma, F., I. Febiyanti, N. Lisdayana, I. W. Arnata et D. Sartika. « Nanocellulose as a new sustainable material for various applications : a review ». Archives of Materials Science and Engineering 2, n^o 109 (1 juin 2021) : 49–64. http://dx.doi.org/10.5604/01.3001.0015.2624.

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Purpose: This paper presents a comprehensive review of nanocellulose and its application in several applications, including composites, biomedical, and food packaging fields. Design/methodology/approach: General explanations about cellulose and nanocellulose have been described. Different types of nanocellulose (cellulose nanofibers, cellulose nanocrystals, bacterial nanocellulose) as well as their isolation processes (mechanical process, chemical process) have been reviewed. Several surface modifications have been explained to improve the dispersion of nanocellulose in non-polar polymers. The possible utilization of nanocellulose in composites, biomedical, and food packaging fields have also been analysed. Findings: This review presents three application fields at once, namely composites, biomedical, and food packaging fields. In the composite field, nanocellulose can be used as a reinforcing agent which increases the mehcnical properties such as tensile strength and toughness, and thermal stability of the final composites. In the biomedical field, nanocellulose is reinforced into hydrogel or composites which will be produced as tissue scaffolding, wound dressing, etc. It is found that the addition of nanocellulose can extend and control the drug release. While in the packaging field, nanocellulose is added into a biopolymer to improve the barrier properties and decrease the water and oxygen vapor transmission rates. Research limitations/implications: Nanocellulose has a hydrophilic nature, thus making it agglomerated and difficult to disperse in most non-polar polymers. Therefore, certain surface modification of nanocellulose are required prior to the preparation of composites or hydrogels.Practical implications: Further research regarding the toxicity of nanocellulose needs to be investigated, especially when applying it in the biomedical and food packaging fields. Originality/value: This review presents three application fields at once, namely composites, biomedical, and food packaging fields.

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Sanders, J. Elliott, Yousoo Han, Todd S. Rushing et Douglas J. Gardner. « Electrospinning of Cellulose Nanocrystal-Filled Poly (Vinyl Alcohol) Solutions : Material Property Assessment ». Nanomaterials 9, n^o 5 (27 mai 2019) : 805. http://dx.doi.org/10.3390/nano9050805.

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Poly (vinyl alcohol) (PVA) and cellulose nanocrystals (CNC) random composite mats were prepared using the electrospinning method. PVA/CNC mats were reinforced with weight concentrations of 0, 20 and 50% CNC (w/w) relative to PVA. Scanning electron microscopy was used to measure the fiber diameter, which ranged from 377 to 416 nm. Thermogravimetric analysis (TGA) confirmed the presence of CNC fibers in the mat fibers which were not visible by scanning electron microscope (SEM). Mechanical testing was conducted using ASTM D 638 on each sample group at 10 mm min−1. Neat PVA and PVA/CNC mats were heat treated at 170 °C for 2h hours, and the morphological structure was maintained with some fiber diameter reduction. Mechanical property results after heat treatment showed a decrease in tensile strength, an increase in tensile stiffness and a decrease in strain to yield (%). This effect was attributable to enhanced diffusion bonding of the mat fiber intersections. The CNC fibers also increased mat stiffness, and reduced strain to yield in non-treated mats. The use of CNCs show potential for compounding into bulk polymer composites as a reinforcement filler, and also show promise for chemical crosslinking attributable to the –OH groups on both the PVA, in addition to esterification of the vinyl group, and CNC.

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Kan, Hong Min, Ning Zhang, Xiao Yang Wang et Hong Sun. « Recent Advances in Hydrogen Storage Materials ». Advanced Materials Research 512-515 (mai 2012) : 1438–41. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.1438.

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An overview of recent advances in hydrogen storage is presented in this review. The main focus is on metal hydrides, liquid-phase hydrogen storage material, alkaline earth metal NC/polymer composites and lithium borohydride ammoniate. Boron-nitrogen-based liquid-phase hydrogen storage material is a liquid under ambient conditions, air- and moisture-stable, recyclable and releases H2controllably and cleanly. It is not a solid material. It is easy storage and transport. The development of a liquid-phase hydrogen storage material has the potential to take advantage of the existing liquid-based distribution infrastructure. An air-stable composite material that consists of metallic Mg nanocrystals (NCs) in a gas-barrier polymer matrix that enables both the storage of a high density of hydrogen and rapid kinetics (loading in <30 min at 200°C). Moreover, nanostructuring of Mg provides rapid storage kinetics without using expensive heavy-metal catalysts. The Co-catalyzed lithium borohydride ammoniate, Li(NH3)4/3BH4 releases 17.8 wt% of hydrogen in the temperature range of 135 to 250 °C in a closed vessel. This is the maximum amount of dehydrogenation in all reports. These will reduce economy cost of the global transition from fossil fuels to hydrogen energy.

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Chen, Shenggui, Junzhong Yang, Yong-Guang Jia, Bingheng Lu et Li Ren. « A Study of 3D-Printable Reinforced Composite Resin : PMMA Modified with Silver Nanoparticles Loaded Cellulose Nanocrystal ». Materials 11, n^o 12 (3 décembre 2018) : 2444. http://dx.doi.org/10.3390/ma11122444.

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With the rapid application of light-curing 3D printing technology, the demand for high-performance polymer resins is increasing. Existing light-curable resins often have drawbacks limiting their clinical applications. This study aims to develop a new type of polymethyl methacrylate (PMMA) composite resins with enhanced mechanical properties, high antibacterial activities and excellent biocompatibilities. A series of reinforced composite resins were prepared by mechanically mixing PMMA with modified cellulose nanocrystals (CNCs), which were coated with polydopamine and decorated by silver nanoparticles (AgNPs) via Tollen reaction. The morphology of CNCs-Ag was observed by transmission electron microscopy and the formation of AgNPs on CNCs was confirmed by X-Ray photoelectron spectroscopy analyses. Functional groups in PMMA-CNCs-Ag composites were verified by Fourier Transform infrared spectroscopy (FTIR) spectroscopy. The mechanical assessment and scanning electron microscopy analysis suggested that the evenly distributed CNCs-AgNPs composite effectively improve mechanical properties of PMMA resin. Cytotoxicity assay and antibacterial activity tests indicated excellent biocompatibility and high antibacterial activities. Furthermore, PMMA with CNCs-AgNPs of 0.1 wt.% (PMMA-CNCs-AgNPs-0.1) possessed the most desirable mechanical properties owing to the homogeneous distribution of AgNPs throughout the resin matrix. This specific composite resin can be used as a functional dental restoration material with potential of other medical applications.

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FRYE, MARSHALL, SHANGRADHANVA E. VASISTH, AMALIE ATASSI, DAVID MAZYCK et JUAN C. NINO. « EFFECT OF DEGREE OF SULFONATION IN NANOCELLULOSE/CHITOSAN COMPOSITE ON ADSORPTION OF CATIONIC DYE AS OPIOID SIMULANT ». Cellulose Chemistry and Technology 55, n^o 1-2 (12 février 2021) : 87–99. http://dx.doi.org/10.35812/cellulosechemtechnol.2021.55.09.

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In this study, the effect of nanocellulose sulfonate group content on adsorption of an opioid simulant was tested. The opioid simulant used was Victoria blue R, an amine dye. Nanocellulose filters were fabricated by crosslinking cellulose nanocrystals (CNCs) with chitosan to improve the mechanical stability of freeze-dried CNCs. Thermogravimetric analysis confirmed the filter’s thermal stability and operating temperatures. Conductometric titration, Fourier transform infrared spectroscopy, and scanning electron microscopy techniques were used to characterize the degree of nanocellulose functionalization. Lastly, the adsorption performance of the sulfonated nanocellulose filter was tested and fitted to kinetic models and adsorption isotherms. The adsorption of the dye by the sulfonated nanocellulose followed pseudo-second order kinetics and the Langmuir isotherm. The maximum adsorption of Victoria blue R dye by sulfonated nanocellulose (68.56 mg/g) is significantly higher than those of other adsorbents, like activated carbon (0.59-2.97 mg/g) and magnetic microparticles (40.98 mg/g). Thus, sulfonated cellulose nanocrystals are a promising material for the sequestration of opioids from water.

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Zhou, Zhong Cheng, Xiong Jun Shen, Xin Fan, Qiu Mei Wu, Hai Lin Yang et Jian Ming Ruan. « Nano-HA Preparation and its Effects on Mechanical Properties of nHA/PLLA/PES Composite Biomaterials ». Advanced Materials Research 668 (mars 2013) : 80–84. http://dx.doi.org/10.4028/www.scientific.net/amr.668.80.

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Nanocrystals hydroxyapatite (nHA) was synthesized and modified chemically, and nanocrystals hydroxyapatite / poly(L-lactide)/poly(ethylene succinate)(nHA/PLLA/PES) composite was prepared by melt-blending using nHA, PLLA and PES as reactants in a stainless steel chamber. The obtained nHA was of high purity and high crystallinity as well, its mean sizes measured from TEM observations were 65±35nm (long axis) and 40±10nm (short axis), and are close to the endosteal needle hydroxyapatite crystals size ((15 ~ 20) nm×60 nm) in the human body. The mechanical properties of nHA/ PLLA/PES blends were determined by bending and tensile tests and the effects of nHA content on the mechanical properties of nHA/PLLA/PES blends were investigated. The blending modulus and tensile modulus increase with the nHA (0,5,10,15and 20 wt.%) content increase, while blending strength increases up to HA mass fraction of 10% and after that decreases. SEM images revealed that the surface changed from rough to smooth with increasing nHA content, especially with nHA content higher than 20%, which implied the failure mechanism of the material changes from ductile to brittle.

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Li, Haipeng, Shuang Yang, Yan Zhao, Taizhe Tan, Xin Wang et Zhumabay Bakenov. « Synthesis of ZnO/Polypyrrole Nanoring Composite as High-Performance Anode Materials for Lithium Ion Batteries ». Journal of Nanomaterials 2019 (3 mars 2019) : 1–8. http://dx.doi.org/10.1155/2019/4702849.

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ZnO has attracted considerable attention as electrode material in lithium-ion battery (LIB) due to its theoretically high capacity. However, poor electronic conductivity and huge volumetric changes during cycling limit its industrial applications. In this work, polypyrrole nanorings (PNRs) were successfully prepared via the solution chemistry method using pyrrole (Py) as raw material, ammonium persulfate (APS) as oxidant, and cetyltrimethyl ammonium bromide (CTAB) as surfactant. The ZnO/PNR composite was synthesized with zinc oxide nanoparticles absorbed on the surface of PPy nanorings through the one-pot in situ sol-gel method. The composite shows a three-dimensional intertwined network structure where the size of polypyrrole nanorings ranges from 80 nm to 100 nm in diameter and the average size of uniformly distributed ZnO nanocrystals is 10.49 nm. The unique three-dimensional conductive framework can provide good electronic contact between the ZnO particles and buffer the volume variation during the lithiation/delithiation processes. As an electrode material for LIBs, the ZnO/PNR composite delivers a first cycle discharge capacity of 1658 mAh g-1 and a capacity retention of 50.7% over 150 cycles at 200 mA g-1, indicating high specific capacity and outstanding cycle stability.

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Sun, G. Y., G. Chen et Guo Liang Chen. « Plastic Deformation Behavior of Bulk Metallic Glass Composite Containing Spherical Ductile Crystalline Precipitates ». Materials Science Forum 539-543 (mars 2007) : 1943–50. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.1943.

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Mechanical alloying (MA), super cooling process, etc. have been used to prepare amorphous phases, metastable solid solutions, nanocrystals, and so on. It is important to consolidate these powders for evaluating the physical properties, and for applications. On the other hand, shock compression can be used as an effective consolidation method for metastable material powders without recrystallization or decomposition. We had prepared metastable transition-metal system bulk alloys and compounds (Fe-Co, Fe-Cu, Fe-W, Co-Cu, Sm-Fe-N systems, etc) by using MA and shock compression. The Fe-Cu and Co-Cu metastable solid solutions showed a fit curve to the Slater-Pauling one. The Co-Cu metastable solid solution bulk alloy showed a magneto-resistance. The Fe-Co fine-grained bulk alloys show the higher coeicivity than that of molten alloy. In this paper, the preparation and magnetic properties of the metastable alloys (Fe-Co, Fe-Cu, Co-Cu systems) are reviewed, and the applications to materials science and engineering are discussed.

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Ben Shalom, Tal, Shylee Belsey, Michael Chasnitsky et Oded Shoseyov. « Cellulose Nanocrystals and Corn Zein Oxygen and Water Vapor Barrier Biocomposite Films ». Nanomaterials 11, n^o 1 (18 janvier 2021) : 247. http://dx.doi.org/10.3390/nano11010247.

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Cellulose nanocrystals (CNC) are well-suited to the preparation of biocomposite films and packaging material due to its abundance, renewability, biodegradability, and favorable film-forming capacity. In this study, different CNC and corn zein (CZ) composite films were prepared by adding CZ to the CNC suspension prior to drying, in order to change internal structure of resulting films. Films were developed to examine their performance as an alternative water vapor and oxygen-barrier for flexible packaging industry. Water vapor permeability (WVP) and oxygen transmission rate (OTR) of the biocomposite films decreased significantly in a specific ratio between CNC and CZ combined with 1,2,3,4-butane tetracarboxylic acid (BTCA), a nontoxic cross linker. In addition to the improved barrier properties, the incorporation of CZ benefitted the flexibility and thermal stability of the CNC/CZ composite films. The toughness increased by 358%, and Young’s modulus decreased by 32% compared with the pristine CNC film. The maximum degradation temperature increased by 26 °C, compared with that of CNC film. These results can be attributed to the incorporation of a hydrophobic protein into the matrix creating hydrophobic interactions among the biocomposite components. SEM and AFM analysis indicated that CZ could significantly affect the CNC arrangement, and the film surface topography, due to the mechanical bundling and physical adsorption effect of CZ to CNC. The presented results indicate that CNC/CZ biocomposite films may find applications in packaging, and in multi-functionalization materials.

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Razieli, Zvie, Roger Rusack et James Kakalios. « Composite Nanocrystalline/Amorphous Thin Films for Particle Detector Applications ». MRS Proceedings 1770 (2015) : 49–54. http://dx.doi.org/10.1557/opl.2015.829.

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ABSTRACTThin films of amorphous silicon with nanocrystalline silicon inclusions are fabricated using a dual plasma PECVD co-deposition system. Raman spectroscopy and X-ray diffraction confirmed the crystallinity of the embedded nanocrystals as well as their diameter, which is varied from 4.3 nm to 17.5 nm. The dark conductivity of the films is highly dependent on the crystal fraction, with a maximum room temperature conductivity found for a crystal concentration of 5.5%, well below the percolation threshold. Proton irradiation at energies of 217 MeV with a total fluence of 5 x1012 protons/cm2 caused no significant radiation damage. The enhancement of the conductivity, along with the absence of radiation damage suggests this material may be a candidate for use in the next generation of particle detectors in the Compact Muon Solenoid in the Large Hadron Collider at CERN.

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Yang, Zunxian, Guodong Du, Zaiping Guo, Xuebin Yu, Zhixin Chen, Peng Zhang, Guonan Chen et Huakun Liu. « Easy preparation of SnO2@carbon composite nanofibers with improved lithium ion storage properties ». Journal of Materials Research 25, n^o 8 (août 2010) : 1516–24. http://dx.doi.org/10.1557/jmr.2010.0194.

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SnO2@carbon nanofibers were synthesized by a combination of electrospinning and subsequent thermal treatments in air and then in argon to demonstrate their potential use as an anode material in lithium ion battery applications. The as-prepared SnO2@carbon nanofibers consist of SnO2 nanoparticles/nanocrystals encapsulated in a carbon matrix and contain many mesopores. Because of the charge pathways, both for the electrons and the lithium ions, and the buffering function provided by both the carbon encapsulating the SnO2 nanoparticles and the mesopores, which tends to alleviate the volumetric effects during the charge/discharge cycles, the nanofibers display a greatly improved reversible capacity of 420 mAh/g after 100 cycles at a constant current of 100 mA/g, and a sharply enhanced reversible capacity at higher rates (0.5, 1, and 2 C) compared with pure SnO2 nanofibers, which makes it a promising anode material for lithium ion batteries.

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Mijailović, Daniel M., Vuk V. Radmilović, Uroš Č. Lačnjevac, Dušica B. Stojanović, Karen C. Bustillo, Vladimir D. Jović, Velimir R. Radmilović et Petar S. Uskoković. « Tetragonal CoMn₂O₄ nanocrystals on electrospun carbon fibers as high-performance battery-type supercapacitor electrode materials ». Dalton Transactions 50, n^o 43 (2021) : 15669–78. http://dx.doi.org/10.1039/d1dt02829d.

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Agrawalla, Rajesh K., Rima Paul, Amit K. Chakraborty et Apurba K. Mitra. « Synthesis and Optical Characterization of Sulfonated Polyaniline/Single-Walled Carbon Nanotube/Zinc Sulphide Nanocomposite ». ISRN Nanotechnology 2013 (4 novembre 2013) : 1–6. http://dx.doi.org/10.1155/2013/253016.

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Polyaniline functionalized with sulfonate groups (SPANI) shows excellent solubility in water. Single-walled carbon nanotubes functionalized with carboxylic groups (f-SWCNTs) and then hybridized with freshly prepared zinc sulphide (ZnS) nanocrystals have been found to be good luminescent material with tuned emission properties. Nanocomposite of sulfonated polyaniline with embedded SWCNT/ZnS nanohybrid fibers has been prepared by a simple solution mixing process and characterized by using high resolution transmission electron microscopy (HRTEM), X-ray diffractometry, Raman spectroscopy, FTIR spectroscopy, and thermogravimetric analysis (TGA). The study of optical properties by UV-vis absorption and photoluminescence spectroscopy reveals that the composite is a luminescent material of enhanced emission intensity in the visible region of the spectrum.

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Tao, Junhong, Jie Yang, Chengxiao Ma, Junfeng Li, Keqing Du, Zhen Wei, Cuizhong Chen, Zhaoyang Wang, Chun Zhao et Xiaoya Deng. « Cellulose nanocrystals/graphene oxide composite for the adsorption and removal of levofloxacin hydrochloride antibiotic from aqueous solution ». Royal Society Open Science 7, n^o 10 (octobre 2020) : 200857. http://dx.doi.org/10.1098/rsos.200857.

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Residual antibiotics in water are often persistent organic pollutants. The purpose of this study was to prepare a cellulose nanocrystals/graphene oxide composite (CNCs-GO) with a three-dimensional structure for the removal of the antibiotic levofloxacin hydrochloride (Levo-HCl) in water by adsorption. The scanning electron microscope, Fourier transform infrared (FT-IR), energy-dispersive spectroscopy, X-ray photoelectron spectroscopy and other characterization methods were used to study the physical structure and chemical properties of the CNCs-GO. The three-dimensional structure of the composite material rendered a high surface area and electrostatic attraction, resulting in increased adsorption capacity of the CNCs-GO for Levo-HCl. Based on the Box–Behnken design, the effects of different factors on the removal of Levo-HCl by the CNCs-GO were explored. The composite material exhibited good antibiotic adsorption capacity, with a removal percentage exceeding 80.1% at an optimal pH of 4, the adsorbent dosage of 1.0 g l −1 , initial pollutant concentration of 10.0 mg l −1 and contact time of 4 h. The adsorption isotherm was well fitted by the Sips model, and kinetics studies demonstrated that the adsorption process conformed to a quasi-second-order kinetics model. Consequently, the as-synthesized CNCs-GO demonstrates good potential for the effective removal of antibiotics such as levofloxacin hydrochloride from aqueous media.

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