scholarly journals Cellulose Nanocrystals: From Classical Hydrolysis to the Use of Deep Eutectic Solvents

2020 ◽  
Author(s):  
Manon Le Gars ◽  
Loreleï Douard ◽  
Naceur Belgacem ◽  
Julien Bras
Keyword(s):  
Mechanical Properties ◽  
Cellulose Nanocrystals ◽  
Specific Area ◽  
Deep Eutectic Solvents ◽  
Barrier Properties ◽  
Chemical Modifications ◽  
Medical Electronic ◽  
High Specific Area ◽  
Rheological Modifier

During the last two decades, interest in cellulosic nanomaterials has greatly increased. Among these nanocelluloses, cellulose nanocrystals (CNC) exhibit outstanding properties. Indeed, besides their high crystallinity, cellulose nanocrystals are interesting in terms of morphology with high aspect ratio (length 100–1000 nm, width 2–15 nm), high specific area, and high mechanical properties. Moreover, they can be used as rheological modifier, emulsifier, or for barrier properties, and their surface chemistry opens the door to numerous feasible chemical modifications, leading to a large panel of applications in medical, electronic, composites, or packaging, for example. Traditionally, their extraction is performed via monitored sulfuric acid hydrolysis, leading to well-dispersed aqueous CNC suspensions; these last bearing negative charges (half-sulfate ester groups) at their surface. More recently, natural chemicals called deep eutectic solvents (DESs) have been used for the production of CNC in a way of green chemistry, and characterization of recovered CNC is encouraging.

Synthesis and characterization of pecan nutshell-based adsorbent with high specific area and high methylene blue adsorption capacity

2019 ◽  
Vol 276 ◽  
pp. 570-576 ◽  
Author(s):  
Hugo H.C. Lima ◽  
Rogério S. Maniezzo ◽  
Maria E.G. Llop ◽  
Vincente L. Kupfer ◽  
Pedro A. Arroyo ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Specific Area ◽  
Synthesis And Characterization ◽  
Methylene Blue Adsorption ◽  
Pecan Nutshell ◽  
High Specific Area

Synthesis and Characterization of Organophilic Clay from Cuban Chiqui Gomez Bentonite

2010 ◽  
Vol 660-661 ◽  
pp. 1093-1098 ◽  
Author(s):  
Guillermo R. Martín Cortés ◽  
Ticiane S. Valera ◽  
Fabio José Esper ◽  
Wildor Theodoro Hennies ◽  
Francisco Rolando Valenzuela-Díaz
Keyword(s):  
Structural Parameters ◽  
Specific Area ◽  
Clay Nanocomposites ◽  
Drilling Fluids ◽  
Octahedral Sheet ◽  
Organophilic Clays ◽  
Swelling Capacity ◽  
Organophilic Clay ◽  
High Specific Area

Smectites are clay mineral with a layered structure and nanometric thickness, high specific area and a huge variety of uses. Consisting on stacked layers of about 1nm thickness, including two silica tetrahedral and one octahedral sheet. Properties of natural Smectites can be enhanced by organic modification, due to the substitution of the exchangeable cations in the interlayer area. In fact, the properties of the modified smectite (organophilic clay) are related to its modified chemical composition and structural parameters. The interaction of smectite clays with surfactants has an important interest in the fields of drilling fluids, paints, cosmetic, ceramic industries and others. Recent applications are: remediation of contaminated areas and polymer/clay nanocomposites. The aim of this paper is to obtain organophilic clays using a bentonite from the Chiqui Gómez deposit in Central Cuba. The raw and organophilic clays were analyzed by DRX, SEM, swelling capacity in organic solvents and others.

scholarly journals High-Oxygen-Barrier Multilayer Films Based on Polyhydroxyalkanoates and Cellulose Nanocrystals

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1443
Author(s):  
Beatriz Melendez-Rodriguez ◽  
Sergio Torres-Giner ◽  
Inmaculada Angulo ◽  
Maria Pardo-Figuerez ◽  
Loïc Hilliou ◽  
...  
Keyword(s):  
Cellulose Nanocrystals ◽  
Cheese Whey ◽  
Adhesive Layer ◽  
Barrier Properties ◽  
Multilayer Films ◽  
High Oxygen ◽  
Multilayer Structures ◽  
Oxygen Barrier ◽  
Contact Transparency

This study reports on the development and characterization of organic recyclable high-oxygen-barrier multilayer films based on different commercial polyhydroxyalkanoate (PHA) materials, including a blend with commercial poly(butylene adipate-co-terephthalate) (PBAT), which contained an inner layer of cellulose nanocrystals (CNCs) and an electrospun hot-tack adhesive layer of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) derived from cheese whey (CW). As a result, the full multilayer structures were made from bio-based and/or compostable materials. A characterization of the produced films was carried out in terms of morphological, optical, mechanical, and barrier properties with respect to water vapor, limonene, and oxygen. Results indicate that the multilayer films exhibited a good interlayer adhesion and contact transparency. The stiffness of the multilayers was generally improved upon incorporation of the CNC interlayer, whereas the enhanced elasticity of the blend was reduced to some extent in the multilayer with CNCs, but this was still much higher than for the neat PHAs. In terms of barrier properties, it was found that 1 µm of the CNC interlayer was able to reduce the oxygen permeance between 71% and 86%, while retaining the moisture and aroma barrier of the control materials.

Synthesis and characterization of mesoporous alumina with high specific area via coprecipitation method

Vacuum ◽  
2016 ◽  
Vol 133 ◽  
pp. 1-6 ◽  
Author(s):  
Lili Zhang ◽  
Yusheng Wu ◽  
Linnan Zhang ◽  
Yuzheng Wang ◽  
Mingchun Li
Keyword(s):  
Specific Area ◽  
Mesoporous Alumina ◽  
Coprecipitation Method ◽  
Synthesis And Characterization ◽  
High Specific Area

scholarly journals Preparation and characterization of bionanocomposite films based on wheat starch and reinforced with cellulose nanocrystals

Cellulose ◽  
2021 ◽  
Author(s):  
Belén Montero ◽  
Maite Rico ◽  
Luis Barral ◽  
Rebeca Bouza ◽  
Joaquín López ◽  
...  
Keyword(s):  
Cellulose Nanocrystals ◽  
Food Packaging ◽  
Environmentally Friendly ◽  
Casting Process ◽  
Barrier Properties ◽  
Gas Diffusion ◽  
Wheat Starch ◽  
Bionanocomposite Films ◽  
Short Time

AbstractIn recent times, the attention of scientific community has been focusing on the replacement of petroleum-based polymers by others more environmentally friendly. In this sense, bionanocomposites based on glycerol-plasticized wheat starch and reinforced with cellulose nanocrystals (CNCs) were prepared by a solvent-casting process to obtain environmentally friendly films. The plasticization process was proven to be complete in the conditions used and no residual crystallinity was observed in any case. The incorporation of CNCs leads to materials with increased rigidity (about 1000% increment in modulus) which is related to a good filler-matrix interaction and to the formation of a rigid crystalline network of cellulose. This fact allowed also to improve the moisture resistance and the barrier properties (in both, oxygen and water vapor as permeant) of the bionanocomposite films due to the formation of a tortuous path, which prevent the gas diffusion. Moreover, the thermal stability of films was not affected by the filler incorporation. These improvements in the properties make these films susceptible to be used in short-time applications in the food packaging industry.

Theoretical Review of Optical Properties of Nanoparticles

2013 ◽  
Vol 8 (2) ◽  
pp. 155892501300800 ◽  
Author(s):  
Amir Rastar ◽  
Mohammad Esmail Yazdanshenas ◽  
Abosaced Rashidi ◽  
Scycd Mansour Bidoki
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Optical Properties ◽  
Specific Area ◽  
Textile Composites ◽  
Optical Scattering ◽  
High Electrical Conductivity ◽  
Particle Type ◽  
Theoretical Methods ◽  
High Specific Area

Nanoparticles are used in a variety of applications and their usage is growing vastly because of their superior characteristics, such as high specific area of contact, great mechanical properties, high electrical conductivity, and high optical scattering efficiency.. Among these numerous properties, optical properties play an important role in either the type of application in which nanoparticles may be utilized or the type of the nanoparticle which may be used for a desired outcome. Many textile products including fibers, fabrics, and textile composites benefit from these capacities of nanoparticles. This paper is a review about the theoretical methods for obtaining optical properties of nanoparticles, noticing that the particle type is selected based on generally used particles like TiO2 in order to acquire needed properties.

Synthesis and Characterization of Stable Mesoporous Multilamellar Silica Vesicles

2007 ◽  
Vol 121-123 ◽  
pp. 473-478 ◽  
Author(s):  
Yu Fang Zhu ◽  
Jian Lin Shi ◽  
Wei Hua Shen
Keyword(s):  
Pore Volume ◽  
Specific Area ◽  
Synthesis And Characterization ◽  
N2 Adsorption ◽  
Structure Directing Agent ◽  
Large Pore Volume ◽  
Desorption Isotherms ◽  
Adsorption Desorption ◽  
High Specific Area

A family of mesoporous multilamellar silica vesicles has been successfully synthesized by using P123 as structure directing agent and hexane as co-surfactant. The structure was characterized with XRD, TEM, and N2 adsorption-desorption isotherms. This multilamellar silica vesicle materials process high specific area, large pore volume, and a bimodale pore size distribution. Furthermore, these materials are stable when the surfactant is removed at 530 oC.

scholarly journals Physical-Mechanical Behavior and Water-Barrier Properties of Biopolymers-Clay Nanocomposites

2021 ◽  
Author(s):  
Heidy Lorena Calambas ◽  
Abril Fonseca ◽  
Dayana Adames ◽  
Yaneli Aguirre-Loredo ◽  
Carolina Caicedo
Keyword(s):  
Mechanical Properties ◽  
Barrier Properties ◽  
Clay Nanocomposites ◽  
Solvent Casting ◽  
New Materials ◽  
Vapour Permeability ◽  
Biodegradable Packaging ◽  
The Matrix ◽  
Response To Water

The preparation of new materials based on starch for the development of biodegradable packaging is increasing, however, the poor properties of this biopolymer for this application causes an area of opportunities for the improvement of water vapour permeability (WVP), mechanical properties, thermal properties, hydrophilicity, water absorption, among others. Hence, starch has been combined with other polymers such as polyvinyl alcohol, which has shown an improvement in the mechanical properties of starch, also, the use of clays suggests that the properties of response to water can be improved. Therefore, in this work, the preparation and characterization of starch-PVA-nanoclay films prepared by solvent casting is reported. The results obtained suggest that the sonication of nanoclay is necessary to reach a good dispersion, which promotes a strong interaction among starch-PVA-nanoclay. In addition, the properties of WVP and mechanical properties of films improved with incorporation of nanoclay, the concentration of 0.5% w/v of nanoclay showed to be the best concentration due to concentrations of 1.0 and 1.5% w/v were poorer than 0.5% w/v. Accordingly, the successful incorporation of nanoclays into the matrix starch-PVA suggests that this material is a good candidate for use as packaging.

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