Preparation of Optically Transparent Films of Poly(methyl methacrylate) (PMMA) and Montmorillonite

2001 ◽  
Vol 703 ◽  
Author(s):  
Elena Vasiliu ◽  
Chyi-Shan Wang ◽  
Richard A. Vaia
Keyword(s):  
Layered Silicate ◽  
Polymer Nanocomposite ◽  
Barrier Properties ◽  
Nanocomposite Material ◽  
Optical Transparency ◽  
Processing Scheme ◽  
Transparent Films ◽  
X Ray Scattering ◽  
Optically Transparent ◽  
High Degree

ABSTRACTTransparent polymeric material with enhanced thermal, mechanical and barrier properties are of special interest for advanced structural, optical and photonic applications. The present paper reports a novel solution processing scheme for fabricating optically transparent polymer nanocomposites involving organophilic layered silicates. It is shown that the nanocomposite material prepared with PMMA and an organically modified montmorrilonite maintains the excellent optical transparency of PMMA. Small-angle x-ray scattering of the polymer nanocomposite material does not show any Bragg's reflection of the organophilic layered silicate. The optical transparency of the nanocomposite material is attributed to a high degree of exfoliation of the montmorrilonite in the polymer matrix.

scholarly journals Optically transparent and very thin structure against electromagnetic pulse (EMP) using metal mesh and saltwater for shielding windows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Duy Tung Phan ◽  
Chang Won Jung
Keyword(s):  
Electromagnetic Pulse ◽  
Low Cost ◽  
High Energy ◽  
Metal Plate ◽  
Optical Transparency ◽  
Shielding Effectiveness ◽  
Concrete Wall ◽  
Metal Mesh ◽  
Wide Range ◽  
Optically Transparent

AbstractAn electromagnetic pulse (EMP) with high energy can damage electronic equipment instantly within a wide range of thousands of kilometers. Generally, a metal plate placed inside a thick concrete wall is used against an EMP, but it is not suitable for an EMP shielding window, which requires not only strong shielding effectiveness (SE) but also optical transparency (OT). In this paper, we propose a very thin and optically transparent structure with excellent SE for EMP shielding window application. The proposed structure consists of a saltwater layer held between two glass substrates and two metal mesh layers on the outside of the glass, with a total thickness of less than 1.5 cm. The SE and OT of the structure are above 80 dB and 45%, respectively, which not only meet the requirement of EMP shielding for military purposes but also retain the procedure of good observation. Moreover, the OT of the structure can be significantly improved using only one metal mesh film (MMF) layer, while the SE is still maintained high to satisfy the required SE for home applicants. With the major advantages of low cost, optical transparency, strong SE, and flexible performance, the proposed structure can be considered a good solution for transparent EMP shielding windows.

scholarly journals Cellulose Nanofibril (CNF) Films and Xylan from Hot Water Extracted Birch Kraft Pulps

2019 ◽  
Vol 9 (16) ◽  
pp. 3436 ◽  
Author(s):  
Marc Borrega ◽  
Hannes Orelma
Keyword(s):  
Food Packaging ◽  
Kraft Pulp ◽  
Barrier Properties ◽  
Hot Water ◽  
Kraft Pulps ◽  
Cellulose Nanofibril ◽  
Vapour Permeability ◽  
Transparent Films ◽  
Cnf Films ◽  
Birch Kraft Pulp

The effects of xylan extraction from birch kraft pulp on the manufacture and properties of cellulose nanofibril (CNF) films were here investigated. Hot water extractions of bleached and unbleached kraft pulps were performed in a flow-through system to remove and recover the xylan. After the extraction, the pulps were oxidized with 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and fibrillated in a high-pressure microfluidizer. Compared to CNF from bleached kraft pulp, the CNF dispersions obtained from water-extracted pulps were less viscous and generally contained a higher amount of microfiber fragments, although smaller in size. In all cases, however, smooth and highly transparent films were produced from the CNF dispersions after the addition of sorbitol as plasticizer. The CNF films made from water-extracted pulps showed a lower tensile strength and ductility, probably due to their lower xylan content, but the stiffness was only reduced by the presence of lignin. Interestingly, the CNF films from water-extracted bleached pulps were less hydrophilic, and their water vapour permeability was reduced up to 25%. Therefore, hot water extraction of bleached birch kraft pulp could be used to produce CNF films with improved barrier properties for food packaging, while obtaining a high-purity xylan stream for other high-value applications.

Polymer nanocomposite coatings based on polyhedral oligosilsesquioxanes: route for industrial manufacturing and barrier properties

2011 ◽  
Vol 13 (10) ◽  
pp. 4691-4701 ◽  
Author(s):  
Ferdinand Männle ◽  
Terje Rosquist Tofteberg ◽  
Morten Skaugen ◽  
Huaitian Bu ◽  
Thijs Peters ◽  
...  
Keyword(s):  
Polymer Nanocomposite ◽  
Barrier Properties ◽  
Nanocomposite Coatings ◽  
Industrial Manufacturing ◽  
Polyhedral Oligosilsesquioxanes

THE STRUCTURAL DEVELOPMENT OF NYLON6/LAYERED SILICATE NANOCOMPOSITE DURING ZONE-DRAWING

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4577-4582
Author(s):  
SUNG SOO HAN ◽  
YANG-WHAN CHO ◽  
SOO-YOUNG PARK
Keyword(s):  
Thermal Analysis ◽  
Dynamic Mechanical Thermal Analysis ◽  
Crystalline Phase ◽  
Layered Silicate ◽  
Phase Region ◽  
Structural Development ◽  
X Ray ◽  
Dynamic Mechanical ◽  
X Ray Scattering ◽  
Degree Of Orientation

The structural development of nylon6/layered silicate nanocomposite during zone-drawing was studied using X-ray scattering and dynamic mechanical thermal analysis. The γ form, which was favored in the pressed film, was converted into the α form during zone-drawing. The newly developed α form, during zone-drawing, has a better orientation than the existing γ form, thus supporting the claim that the α form crystallizes away from the polymer-silicate inter-phase region during drawing. The degree of orientation of the layered silicate, projected along the TD direction, increases with the increase of the draw ratio, suggesting that the layered silicate has become straighter during zone-drawing, although the layered silicate within the zone-drawn film buckled perpendicular to the draw direction. The β transition of the dynamic mechanical thermal analysis is independent of the crystalline phase, although the α transition is strongly dependent upon the crystalline phase. This can be explained by the free volume that exists in the inter-phase between the γ lamellar and the layered silicate.

scholarly journals Room Temperature Gas Multisensor System Based on a Novel Polymer Nanocomposite Material

2014 ◽  
Vol 87 ◽  
pp. 152-155
Author(s):  
Mikhail Yablokov ◽  
Alexey Vasiliev ◽  
Andrey Varfolomeev ◽  
Sergey Zavyalov
Keyword(s):  
Room Temperature ◽  
Polymer Nanocomposite ◽  
Nanocomposite Material ◽  
Multisensor System

scholarly journals Nitrosative stress sensing inPorphyromonas gingivalis: structure of and heme binding by the transcriptional regulator HcpR

2019 ◽  
Vol 75 (4) ◽  
pp. 437-450 ◽  
Author(s):  
B. Ross Belvin ◽  
Faik N. Musayev ◽  
John Burgner ◽  
J. Neel Scarsdale ◽  
Carlos R. Escalante ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Nitrosative Stress ◽  
Gas Sensing ◽  
Anaerobic Bacteria ◽  
Heme Iron ◽  
Heme Binding ◽  
X Ray ◽  
X Ray Scattering ◽  
Stress Sensing ◽  
High Degree

Although the HcpR regulator plays a vital step in initiation of the nitrosative stress response in many Gram-negative anaerobic bacteria, the molecular mechanisms that it uses to mediate gas sensing are not well understood. Here, a 2.6 Å resolution crystal structure of the N-terminal sensing domain of the anaerobic periodontopathogenPorphyromonas gingivalisHcpR is presented. The protein has classical features of the regulators belonging to the FNR-CRP family and contains a hydrophobic pocket in its N-terminal sensing domain. It is shown that heme bound to HcpR exhibits heme iron as a hexacoordinate system in the absence of nitric oxide (NO) and that upon nitrosylation it transitions to a pentacoordinate system. Finally, small-angle X-ray scattering experiments on full-length HcpR reveal that the C-terminal DNA-binding domain of HcpR has a high degree of interdomain flexibility.

scholarly journals Structure and oligomerization state of the C-terminal region of the Middle East respiratory syndrome coronavirus nucleoprotein

2019 ◽  
Vol 75 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Thi Hong Van Nguyen ◽  
Julie Lichière ◽  
Bruno Canard ◽  
Nicolas Papageorgiou ◽  
Sarah Attoumani ◽  
...  
Keyword(s):  
Middle East ◽  
Structural Information ◽  
Respiratory Illness ◽  
Middle East Respiratory Syndrome ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Nucleoprotein N ◽  
High Degree ◽  
Genome Encapsidation

Middle East respiratory syndrome coronavirus (MERS-CoV) is a human pathogen responsible for a severe respiratory illness that emerged in 2012. Structural information about the proteins that constitute the viral particle is scarce. In order to contribute to a better understanding of the nucleoprotein (N) in charge of RNA genome encapsidation, the structure of the C-terminal domain of N from MERS-CoV obtained using single-crystal X-ray diffraction is reported here at 1.97 Å resolution. The molecule is present as a dimer in the crystal structure and this oligomerization state is confirmed in solution, as measured by additional methods including small-angle X-ray scattering measurements. Comparisons with the structures of the C-terminal domains of N from other coronaviruses reveals a high degree of structural conservation despite low sequence conservation, and differences in electrostatic potential at the surface of the protein.

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