Multi-layer MoS2 : An Effective Barrier Enhancer and a Promising Nanofiller for Metal Protection

Abstract Two-dimensional nanomaterials are of great interest because of their unique properties and the great application potential in various fields. In this study, the performance of few-layer MoS2 nanosheets (MDNSs) as new nanofillers to enhance the barrier properties of poly(vinyl butyral) (PVB) is investigated. Gas permeability tests show that well-dispersed MDNSs can prevent at least 98% of oxygen molecules and 31% of water vapour from penetrating through the matrix of MDNS/PVB composites. Electrochemical analyses reveal that the corrosion rate of brass coated with the resulting composite coating is as low as 1.35×10− 8 mm/year, which is six orders of magnitude smaller than that of brass protected by a pristine PVB coating. These results indicate that MDNSs are highly effective barrier enhancers and suitable candidate materials for metal protection.

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Nanocomposite Barrier Coatings for Elastomeric Applications

MRS Proceedings ◽

10.1557/proc-733-t4.7 ◽

2002 ◽

Vol 733 ◽

Cited By ~ 1

Author(s):

H.A. Goldberg ◽

C.A. Feeney ◽

D.P. Karim ◽

M. Farrell

Keyword(s):

Aspect Ratio ◽

Gas Permeability ◽

Barrier Properties ◽

Butyl Rubber ◽

Commercial Application ◽

Tennis Ball ◽

Unique Combination ◽

Barrier Coatings ◽

The Matrix ◽

Very High

AbstractInMat LLC has developed aqueous, non-hazardous nanocomposite dispersions with a unique combination of barrier properties and flexibility. Using butyl rubber as the matrix, and very high aspect ratio vermiculite filler, flexible coatings with gas permeability 30-300 times lower than butyl rubber have been produced.[1,2] These coatings have been shown to be undamaged by strains up to 20%. The first commercial application of this technology (sold under InMat's trademark Air D-FenseTM) is in Wilson's new, longer life, Double CoreTM tennis ball.

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Polypropylene/montmorillonite Nanocomposites for Food Packaging

e-Polymers ◽

10.1515/epoly.2007.7.1.305 ◽

2007 ◽

Vol 7 (1) ◽

Cited By ~ 1

Author(s):

Mohammad Sirousazar ◽

Mortaza Yari ◽

Bahram Fathi Achachlouei ◽

Jalal Arsalani ◽

Yagoub Mansoori

Keyword(s):

Food Packaging ◽

Gas Permeability ◽

Tensile Modulus ◽

Barrier Properties ◽

X Ray Diffraction ◽

Transmission Electron ◽

Blending Method ◽

The Matrix ◽

Silicate Layers ◽

Montmorillonite Nanocomposites

AbstractPolypropylene / organically modified montmorillonite nanocomposites were prepared using polypropylene-graft-maleic anhydride as compatibilizer by the melt blending method. The structural, mechanical and gas barrier properties of the prepared nanocomposites containing various amounts of organoclay (i.e. 0, 2, 5, 7 and 10 wt%) were investigated to evaluate their potential as food packaging materials. The X-ray diffraction (XRD) profiles of the nanocomposites and the transmission electron microscopy (TEM) micrograph showed that polypropylene chains have intercalated between silicate layers of organoclay. The mechanical properties tests showed that the tensile modulus and strength of the nanocomposites increased on increasing the clay loading, while the strain at the break decreased. The gas permeability tests demonstrated that adding organoclay into polypropylene matrix enhances the barrier property of the matrix against O2 , CO2 and water vapour.

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Dynamic Emergence of Nanostructure and Transport Properties in Perfluorinated Sulfonic Acid Ionomers

10.26434/chemrxiv.12302693.v1 ◽

2020 ◽

Author(s):

Adlai Katzenberg ◽

Debdyuti Mukherjee ◽

Peter J. Dudenas ◽

Yoshiyuki Okamoto ◽

Ahmet Kusoglu ◽

...

Keyword(s):

Rate Constant ◽

Sulfonic Acid ◽

Mass Fraction ◽

Gas Permeability ◽

Transport Processes ◽

Segmental Mobility ◽

The Matrix ◽

Swelling Rate ◽

Ion Conducting ◽

Perfluorinated Sulfonic Acid

Limitations in fuel cell electrode performance have motivated the development of ion-conducting binders (ionomers) with high gas permeability. Such ionomers have been achieved by copolymerization of perfluorinated sulfonic acid (PFSA) monomers with bulky and asymmetric monomers, leading to a glassy ionomer matrix with chemical and mechanical properties that differ substantially from common PFSA ionomers (e.g., Nafion™). In this study, we use perfluorodioxolane-based ionomers to provide fundamental insights into the role of the matrix chemical structure on the dynamics of structural and transport processes in ion-conducting polymers. Through in-situ water uptake measurements, we demonstrate that ionomer water sorption kinetics depend strongly on the properties and mass fraction of the matrix. As the PFSA mass fraction was increased from 0.26 to 0.57, the Fickian swelling rate constant decreased from 0.8 s-1 to 0.2 s-1, while the relaxation rate constant increased from 3.1×10-3 s-1 to 4.0×10-3. The true swelling rate, in nm s-1, was determined by the chemical nature of the matrix; all dioxolane-containing materials exhibited swelling rates ~1.5 - 2 nm s-1 compared to ~3 nm s-1 for Nafion. Likewise, Nafion underwent relaxation at twice the rate of the fastest-relaxing dioxolane ionomer. Reduced swelling and relaxation kinetics are due to limited matrix segmental mobility of the dioxolane-containing ionomers. We demonstrate that changes in conductivity are strongly tied to the polymer relaxation, revealing the decoupled roles of initial swelling and relaxation on hydration, nanostructure, and ion transport in perfluorinated ionomers.

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Tunable characteristics of low-frequency bandgaps in two-dimensional multivibrator phononic crystal plates under prestrain

Scientific Reports ◽

10.1038/s41598-021-87904-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hai-Fei Zhu ◽

Xiao-Wei Sun ◽

Ting Song ◽

Xiao-Dong Wen ◽

Xi-Xuan Liu ◽

...

Keyword(s):

Phononic Crystal ◽

Real Life ◽

Low Frequency ◽

Acoustic Vibration ◽

Crystal Plate ◽

Frequency Noise ◽

Two Dimensional ◽

The Matrix ◽

Noise Frequency ◽

Realtime Control

AbstractIn view of the influence of variability of low-frequency noise frequency on noise prevention in real life, we present a novel two-dimensional tunable phononic crystal plate which is consisted of lead columns deposited in a silicone rubber plate with periodic holes and calculate its bandgap characteristics by finite element method. The low-frequency bandgap mechanism of the designed model is discussed simultaneously. Accordingly, the influence of geometric parameters of the phononic crystal plate on the bandgap characteristics is analyzed and the bandgap adjustability under prestretch strain is further studied. Results show that the new designed phononic crystal plate has lower bandgap starting frequency and wider bandwidth than the traditional single-sided structure, which is due to the coupling between the resonance mode of the scatterer and the long traveling wave in the matrix with the introduction of periodic holes. Applying prestretch strain to the matrix can realize active realtime control of low-frequency bandgap under slight deformation and broaden the low-frequency bandgap, which can be explained as the multiple bands tend to be flattened due to the localization degree of unit cell vibration increases with the rise of prestrain. The presented structure improves the realtime adjustability of sound isolation and vibration reduction frequency for phononic crystal in complex acoustic vibration environments.

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Divergent ⇒ complex amplitudes in two dimensional string theory

Journal of High Energy Physics ◽

10.1007/jhep02(2021)086 ◽

2021 ◽

Vol 2021 (2) ◽

Author(s):

Ashoke Sen

Keyword(s):

Scattering Amplitudes ◽

String Theory ◽

Matrix Model ◽

Two Dimensional ◽

Full Matrix ◽

Instanton Contribution ◽

The Matrix ◽

Theory Result ◽

The One ◽

Remarkable Agreement

Abstract In a recent paper, Balthazar, Rodriguez and Yin found remarkable agreement between the one instanton contribution to the scattering amplitudes of two dimensional string theory and those in the matrix model to the first subleading order. The comparison was carried out numerically by analytically continuing the external energies to imaginary values, since for real energies the string theory result diverges. We use insights from string field theory to give finite expressions for the string theory amplitudes for real energies. We also show analytically that the imaginary parts of the string theory amplitudes computed this way reproduce the full matrix model results for general scattering amplitudes involving multiple closed strings.

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Assessment of Graphene Oxide and Nanoclay Based Hybrid Filler in Chlorobutyl-Natural Rubber Blend for Advanced Gas Barrier Applications

Nanomaterials ◽

10.3390/nano11051098 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1098

Author(s):

Jibin Keloth Paduvilan ◽

Prajitha Velayudhan ◽

Ashin Amanulla ◽

Hanna Joseph Maria ◽

Allisson Saiter-Fourcin ◽

...

Keyword(s):

Graphene Oxide ◽

Carbon Black ◽

Natural Rubber ◽

Gas Permeability ◽

Chemical Properties ◽

Barrier Properties ◽

Hybrid Filler ◽

Physical And Chemical ◽

Chlorobutyl Rubber ◽

And Chemical Properties

Nanomaterials have engaged response from the scientific world in recent decades due to their exceptional physical and chemical properties counter to their bulk. They have been widely used in a polymer matrix to improve mechanical, thermal, barrier, electronic and chemical properties. In rubber nanocomposites, nanofillers dispersion and the interfacial adhesion between polymer and fillers influences the composites factual properties. In the present work, a comparison of the hybrid effects of carbon black with two different nanofillers (graphene oxide and nanoclay) was studied. The 70/30 composition of chlorobutyl rubber/natural rubber elastomer blend was taken as per the blend composition optimized from our previous studies. The hybrid effects of graphene oxide and nanoclay in dispersing the nanofillers were studied mainly by analyzing nanocomposite barrier properties. The results confirm that the combined effect of carbon black with graphene oxide and nanoclay could create hybrid effects in decreasing the gas permeability. The prepared nanocomposites which partially replace the expensive chlorobutyl rubber can be used for tyre inner liner application. Additionally, the reduction in the amount of carbon black in the nanocomposite can be an added advantage of considering the environmental and economic factors.

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A new fourth-order explicit group method in the solution of two-dimensional fractional Rayleigh–Stokes problem for a heated generalized second-grade fluid

Advances in Difference Equations ◽

10.1186/s13662-020-03061-6 ◽

2020 ◽

Vol 2020 (1) ◽

Author(s):

Muhammad Asim Khan ◽

Norhashidah Hj. Mohd Ali ◽

Nur Nadiah Abd Hamid

Keyword(s):

Finite Difference ◽

Stokes Problem ◽

Stability And Convergence ◽

Second Grade ◽

Group Method ◽

Two Dimensional ◽

Second Grade Fluid ◽

The Matrix ◽

Grade Fluid ◽

Generalized Second Grade Fluid

Abstract In this article, a new explicit group iterative scheme is developed for the solution of two-dimensional fractional Rayleigh–Stokes problem for a heated generalized second-grade fluid. The proposed scheme is based on the high-order compact Crank–Nicolson finite difference method. The resulting scheme consists of three-level finite difference approximations. The stability and convergence of the proposed method are studied using the matrix energy method. Finally, some numerical examples are provided to show the accuracy of the proposed method.

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Nanocomposites Materials of PLA Reinforced with Nanoclays Using a Masterbatch Technology: A Study of the Mechanical Performance and Its Sustainability

Polymers ◽

10.3390/polym13132133 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2133

Author(s):

Helena Oliver-Ortega ◽

Josep Tresserras ◽

Fernando Julian ◽

Manel Alcalà ◽

Alba Bala ◽

...

Keyword(s):

Food Packaging ◽

Mechanical Performance ◽

Polymeric Materials ◽

Barrier Properties ◽

Food Tray ◽

Environmental Concerns ◽

Poly Lactic Acid ◽

The Matrix ◽

Surface Modified ◽

Being Moved

Packaging consumes around 40% of the total plastic production. One of the most important fields with high requirements is food packaging. Food packaging products have been commonly produced with petrol polymers, but due to environmental concerns, the market is being moved to biopolymers. Poly (lactic acid) (PLA) is the most promising biopolymer, as it is bio-based and biodegradable, and it is well established in the market. Nonetheless, its barrier properties need to be enhanced to be competitive with other polymers such as polyethylene terephthalate (PET). Nanoclays improve the barrier properties of polymeric materials if correct dispersion and exfoliation are obtained. Thus, it marks a milestone to obtain an appropriate dispersion. A predispersed methodology is proposed as a compounding process to improve the dispersion of these composites instead of common melt procedures. Afterwards, the effect of the polarity of the matrix was analyzing using polar and surface modified nanoclays with contents ranging from 2 to 8% w/w. The results showed the suitability of the predispersed and concentrated compound, technically named masterbatch, to obtain intercalated structures and the higher dispersion of polar nanoclays. Finally, the mechanical performance and sustainability of the prepared materials were simulated in a food tray, showing the best assessment of these materials and their lower fingerprint.

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Lymphocyte locomotion and attachment on two-dimensional surfaces and in three-dimensional matrices

The Journal of Cell Biology ◽

10.1083/jcb.92.3.747 ◽

1982 ◽

Vol 92 (3) ◽

pp. 747-752 ◽

Cited By ~ 109

Author(s):

WS Haston ◽

JM Shields ◽

PC Wilkinson

Keyword(s):

Three Dimensional ◽

Two Dimensional ◽

Collagen Gels ◽

Peripheral Lymph Node ◽

Cellulose Esters ◽

Peripheral Lymph ◽

The Matrix ◽

Identical Material ◽

Variable Morphology ◽

Collagen Lattices

The adhesion and locomotion of mouse peripheral lymph node lymphocytes on 2-D protein- coated substrata and in 3-D matrices were compared. Lymphocytes did not adhere to, or migrate on, 2-D substrata suck as serum- or fibronectin-coated glass. They did attach to and migrate in hydrated 3-D collagen lattices. When the collagen was dehydrated to form a 2-D surface, lymphocyte attachment to it was reduced. We propose that lymphocytes, which are poorly adhesive, are able to attach to and migrate in 3-D matrices by a nonadhesive mechanism such as the extension and expansion of pseudopodia through gaps in the matrix, which could provide purchase for movement in the absence of discrete intermolecular adhesions. This was supported by studies using serum-coated micropore filters, since lymphocytes attached to and migrated into filters with pore sizes large enough (3 or 8 mum) to allow pseudopod penetration but did not attach to filters made of an identical material (cellulose esters) but of narrow pore size (0.22 or 0.45 mum). Cinematographic studies of lymphocyte locomotion in collagen gels were also consistent with the above hypothesis, since lymphocytes showed a more variable morphology than is typically seen on plane surfaces, with formation of many small pseudopodia expanded to give a marked constriction between the cell and the pseudopod. These extensions often remained fixed with respect to the environment as the lymphocyte moved away from or past them. This suggests that the pseudopodia were inserted into gaps in the gel matrix and acted as anchorage points for locomotion.

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Finite Element Study of Oxygen Diffusion in the Intervertebral Disc

10.1115/imece2000-2622 ◽

2000 ◽

Author(s):

E. Sélard ◽

A. Shirazi-Adl ◽

J. P. G. Urban

Keyword(s):

Intervertebral Disc ◽

Blood Supply ◽

Oxygen Diffusion ◽

Consumption Rate ◽

The Body ◽

Cellular Viability ◽

Two Dimensional ◽

Concentration Gradients ◽

Exchange Area ◽

The Matrix

Abstract The intervertebral disc consists of a water-rich extra-cellular matrix which is synthesized and maintained by its cells. The disc is the largest avascular tissue in the body with its cells lying as much as 8mm away from the blood supply. Nutrients, essential for maintaining cellular viability, diffuse through the matrix from blood supply under a concentration gradient arising from cellular demand. The oxygen concentration gradients in the intervertebral disc are investigated to examine the effects of exchange area and disc thickness on oxygen flux in the disc. The concentration gradients are computed using the two-dimensional Poisson’s equation and measured values for oxygen consumption rate and oxygen diffusion.

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