scholarly journals Preparation of Cellulose Films from Sustainable CO2/DBU/DMSO System

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 994 ◽  
Author(s):  
Longming Jin ◽  
Jianyun Gan ◽  
Gang Hu ◽  
Long Cai ◽  
Zaiquan Li ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Food Packaging ◽  
Solvent System ◽  
Light Transmittance ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Cellulose Films ◽  
Atomic Force ◽  
Dmso System ◽  
Amorphous Structures

Cellulose films are regarded as sustainable materials having wide applications in food packaging, separation, etc. Their preparation substantially relies on sufficient dissolution. Herein, various celluloses adequately dissolved in a new solvent system of carbon dioxide,1, 8-diazabicyclo [5.4.0] undec-7-ene and dimethyl sulfoxide (CO2/DBU/DMSO) were made in to films using different regeneration reagents. The films regenerated from ethanol and methanol presented homogeneous and smooth surfaces, while those from 5 wt % NaOH (aq.) and 5 wt % H2SO4 (aq.) showed rough surfaces, as analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The films regenerated from 5 wt % NaOH (aq.) and 5 wt % H2SO4 (aq.) rendered cellulose II structures, while those regenerated from alcohols had amorphous structures as evidenced using fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results. The films made of microcrystalline cellulose had a good light transmittance of about 90% at 800 nm with a tensile strength of 55 MPa and an elongation break of 6.5%, while those from wood pulp cellulose demonstrated satisfactory flexibility with a tensile strength of 91 MPa and an elongation break of 9.0%. This research reports a simple, environmental, and sustainable method to prepare cellulose films of good mechanical properties.

scholarly journals Preparation And Properties Of Bionanocomposite Films Reinforced With Nanocellulose Isolated From Moroccan Alfa Fibres

2015 ◽  
Vol 15 (3) ◽  
pp. 164-172 ◽  
Author(s):  
Benyoussif Youssef ◽  
Aboulhrouz Soumia ◽  
El Achaby Mounir ◽  
Cherkaoui Omar ◽  
Lallam Abdelaziz ◽  
...  
Keyword(s):  
Carboxymethyl Cellulose ◽  
Food Packaging ◽  
Fourier Transforms ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
Vapour Permeability ◽  
Force Microscopy ◽  
Atomic Force ◽  
Bionanocomposite Films

AbstractNanocellulose (NC) were extracted from the Moroccan Alfa plant (Stipa tenacissima L.) and characterised. These Alfa cellulosic nanoparticles were used as reinforcing phase to prepare bionanocomposite films using carboxymethyl cellulose as matrix. These films were obtained by the casting/evaporation method. The crystallinity of NC was analysed by X-ray diffraction, the dimension of NC by atomic force microscopy, molecular interactions due to incorporation of NC in carboxymethyl cellulose (CMC) matrix were supported by Fourier transforms infrared (FTIR) spectroscopy. The properties of the ensuing bionanocomposite films were investigated using tensile tests, water vapour permeability (WVP) study and thermogravimetric analysis. With the progress of purification treatment of cellulose, the crystallinity is improved compared to the untreated fibres; this can be explained by the disappearance of the amorphous areas in cellulose chain of the plant. Consequently, the tensile modulus and tensile strength of CMC film increased by 60 and 47%, respectively, in the bionanocomposite films with 10 wt% of NC, and decrease by 8.6% for WVP with the same content of NC. The NC obtained from the Moroccan Alfa fibres can be used as a reinforcing agent for the preparation of bionanocomposites, and they have a high potential for the development of completely biodegradable food packaging materials.

scholarly journals New thermoplastic poly(carbonate-urethane) elastomers

2011 ◽  
Vol 13 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Anna Kultys ◽  
Magdalena Rogulska
Keyword(s):  
Soft Segment ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Melt Polymerization ◽  
Atomic Force ◽  
Amorphous Structures ◽  
A Chain ◽  
Poly Carbonate

New thermoplastic poly(carbonate-urethane) elastomersTwo series of novel thermoplastic poly(carbonate-urethane) elastomers, with different hard-segment content (30 - 60 wt %), were synthesized by melt polymerization from poly(hexane-1,6-diyl carbonate) diol of Mn= 2000 as a soft segment, 4,4'-diphenylmethane diisocyanate (MDI) or hexane-1,6-diyl diisocyanate (HDI) and 6,6'-[methylenebis(1,4-phenylenemethylenethio)]dihexan-1-ol as a chain extender. The structure and basic properties of the polymers were examined by Fourier transform infrared spectroscopy, X-ray diffraction analysis, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, Shore hardness and tensile tests. The resulting TPUs were colorless polymers, showing almost amorphous structures. The MDI-based TPUs showed higher tensile strengths (up to 21.3 MPa vs. 15.8 MPa) and elongations at break (up to 550% vs. 425%), but poorer low-temperature properties than the HDI-based analogs.

scholarly journals All-Cellulose Nanocomposite Made from Nanofibrillated Cellulose

2010 ◽  
Vol 19 (6) ◽  
pp. 096369351001900 ◽  
Author(s):  
Hossein Yousefi ◽  
Takashi Nishino ◽  
Mehdi Faezipour ◽  
Ghanbar Ebrahimi ◽  
Alireza Shakeri ◽  
...  
Keyword(s):  
Tensile Tests ◽  
Solvent System ◽  
Nanofibrillated Cellulose ◽  
Dissolution Time ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Cellulose Nanocomposites ◽  
Core Part

Commercial microfibrillated cellulose (MFC) was ground and turned into nanofibrillated cellulose (NFC), then all-cellulose nanocomposites (ACNC) were prepared by partially dissolving method. The nanocomposites, with different ratios of undissolved core part of NFC in a matrix of partially dissolved skin part of NFC, were produced using DMAc/LiCl as solvent system. Five dissolution times of 5, 10, 20, 30 and 60 minutes were used as variables and the results were compared with the properties of neat MFC and NFC sheets. The structure and properties of MFC, NFC and nanocomposites were characterized using atomic force microscopy, field emission scanning electron microscopy, X-ray diffraction and tensile tests. The mechanical properties of NFC are significantly larger than those of MFC. As dissolution time increased, the apparent crystallinity of ACNC decreased and more amount of matrix covered the nanofibre surfaces. The ACNC showed best tensile strength (156 MPa) and Young's modulus (13.2 GPa) at 10 minutes dissolution time. The advantage of ACNC is that they are fully bio-based, easily recyclable, fully biodegradable and strong materials.

scholarly journals Local Surface Electric Field’s Effect on Adsorbed Proteins’ Orientation

Surfaces ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 415-431 ◽  
Author(s):  
Larbi Filali ◽  
Yamina Brahmi ◽  
Jamal Dine Sib ◽  
Yahya Bouizem ◽  
Djamel Benlakehal ◽  
...  
Keyword(s):  
Electric Fields ◽  
Electrostatic Interactions ◽  
Nanocrystalline Silicon ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Adsorbed Protein ◽  
Adsorbed Proteins ◽  
Amorphous Structures ◽  
Protein Surface Interactions

Hydrogenated nanocrystalline silicon, while being non-charged and non-polar, could be an ideal candidate for the non-covalent and orientation-controlled immobilization of biomolecules thanks to local electric fields around nanocrystals. To that effect, the adsorption of bovine serum albumin on substrates with different densities of nanocrystals, revealed by Raman spectroscopy and X-ray diffraction, was studied using infrared spectroscopy and atomic force microscopy. It was found that the protein–surface interactions followed different mechanisms depending on the nanostructure at the surface: hydrophobic on the non-crystalline part of the surface and electrostatic around the crystalline part. These electrostatic interactions were driven by the electric fields that arose at the junction between crystalline and amorphous structures. These electric fields were found to be strong enough to interact with the amide dipoles, thereby reorienting the adsorbed protein molecules on this part of the surface. Nevertheless, the adsorbed proteins were found to be denatured, which was due to the surface chemistry, and not affected by the nanostructure.

Development and characterization of novel polybutylene nanocomposites

2016 ◽  
Vol 51 (1) ◽  
pp. 95-108 ◽  
Author(s):  
Khaled Alfadhel ◽  
Adam Al-Mulla ◽  
Bader Al-Busairi
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Initial Period ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Elongation At Break ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
The Matrix

Polybutylene/starch/nanoclay composite blends were prepared by melt extrusion technique. Maleic anhydride grafted polybutylene was used as a compatibilizer. The nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, rheological, and mechanical analysis. Addition of compatibilizer to the polybutylene/starch/nanoclay showed dispersion and nucleation related to the nanoclay in the polybutylene matrix. An increase in the mechanical properties like modulus and tensile strength at break and a decrease in the elongation at break were observed on the addition of compatibilizer to the matrix compared to that of uncompatibilized matrix. The biodegradability of the nanocomposites was studied using the landfill burial test. The blends subjected to the burial test were evaluated for their tensile properties. The results revealed that the tensile strength and elongation at break of the compatibilized nanocomposites decreased after 80 days of land burial test compared to the initial period.

scholarly journals Investigations of the formation of zeolite ZSM-39 (MTN)

2019 ◽  
Vol 97 (12) ◽  
pp. 840-847 ◽  
Author(s):  
Zheng Sonia Lin ◽  
Donghan Chen ◽  
Heng-Yong Nie ◽  
Y.T. Angel Wong ◽  
Yining Huang
Keyword(s):  
Eutectic Mixture ◽  
Solvent System ◽  
Layer Growth ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Fluoride Ions ◽  
Subsequent Formation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Crystallization Conditions

Crystallization of zeolite ZSM-39 (MTN), a clathrate and silicate analogue of the 17 Å cubic gas hydrate, was examined in a solvent system involving a tetramethylammonium chloride – 1,6-hexanediol deep eutectic mixture and significant amount of water. The crystallization process was followed by powder X-ray diffraction (PXRD), and solid-state nuclear magnetic resonance (SSNMR) techniques involving several nuclei such as 19F, 29Si, and 13C. The results indicate that the crystallization starts from the arrangement of amorphous Si–O–Si species around the tetramethylammonium ions and subsequent formation of the cages in the precursors similar to [51264] cages in the MTN topology. The larger [51264] cages are then connected via the smaller [512] cages containing the fluoride ions to form the final MTN structure. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses show that the crystal growth rates along <100> and <111> directions are roughly the same, suggesting that the (100) and (111) planes have similar stability under the crystallization conditions used. AFM study also shows that the freshly born nuclei on the (100) face are of a height of 2 nm, suggesting a layer by layer growth of the polyhedral crystal.

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optical Quality ◽  
X Ray Diffraction ◽  
Interface Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

scholarly journals Ultrafine metal-polymer catalysts based on polyconjugated systems for Fisher–Tropsch synthesis

2020 ◽  
Vol 92 (6) ◽  
pp. 977-984
Author(s):  
Mayya V. Kulikova ◽  
Albert B. Kulikov ◽  
Alexey E. Kuz’min ◽  
Anton L. Maximov
Keyword(s):  
Tropsch Synthesis ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
Force Microscopy ◽  
Composite Catalysts ◽  
Fe Catalyst ◽  
Atomic Force ◽  
And Function ◽  
Metal Polymer

AbstractFor previously studied Fischer–Tropsch nanosized Fe catalyst slurries, polymer compounds with or without polyconjugating structures are used as precursors to form the catalyst nanomatrix in situ, and several catalytic experiments and X-ray diffraction and atomic force microscopy measurements are performed. The important and different roles of the paraffin molecules in the slurry medium in the formation and function of composite catalysts with the two types of aforementioned polymer matrices are revealed. In the case of the polyconjugated polymers, the alkanes in the medium are “weakly” coordinated with the metal-polymer composites, which does not affect the effectiveness of the polyconjugated polymers. Otherwise, alkane molecules form a “tight” surface layer around the composite particles, which create transport complications for the reagents and products of Fischer-Tropsch synthesis and, in some cases, can change the course of the in situ catalyst formation.

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