scholarly journals Structural Investigation: Anionic Polymerization of Acrylamide under Microwave Irradiation using Maghnite-Na+ Clay (Algerien MMT) as Initiator

2018 ◽  
Vol 13 (2) ◽  
pp. 262 ◽  
Author(s):  
Abdelkader Rahmouni ◽  
Mohammed Belbachir ◽  
Molkheir Ayat
Keyword(s):  
Microwave Irradiation ◽  
Anionic Polymerization ◽  
Structural Investigation ◽  
Aqueous Sodium Hydroxide ◽  
Reaction Engineering ◽  
Purchase Price ◽  
Similar Composition ◽  
Composition And Structure ◽  
Naoh Solution ◽  
Anionic Polyacrylamide

Intercalation of acrylamide into interlayer spaces of natural  montmorillonite called maghnite (Algerian MMT) by the free solvent polymerization technique under micowave irradiation was studied. The transformation was carried out with using both the raw (Maghnite-Na fin) and treated clay (Maghnite-Na+ fin) in aqueous sodium hydroxide NaOH solution (1 M). It was shown that no initial modification of the layered mineral (by ion-exchange with Na+ cations or organophilization) is needed for the successful introduction of anionic hydrogels into the interlayer gallery. The goal of the present study was to synthesis anionic polyacrylamide/Maghnite composite with similar composition and structure to that synthesized of other catalyst. The Maghnite catalyst has a significant role in the industrial scale. In fact, the use of Maghnite is preferred for its many advantages: a very low purchase price compared to other catalysts, the easy removal of the reaction mixture. The anionic sodium-clay polyacrylamide material exhibited a tendency to the formation of exfoliated structure. The synthesized hydrogels, as monitored by the swelling behavior, were characterized by Fourier transform infrared and 1HNMR analysis. Copyright © 2018 BCREC Group. All rights reservedReceived: 24th June 2017; Revised: 13rd December 2017; Accepted: 14th December 2017; Available online: 11st June 2018; Published regularly: 1st August 2018How to Cite: Rahmouni, R., Belbachir, M., Ayat, M. (2018). Structural Investigation: Anionic Polymerization of Acrylamide under Microwave Irradiation using Maghnite-Na+ Clay (Algerien MMT) as Initiator. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (2): 262-274 (doi:10.9767/bcrec.13.2.1308.262-274) 

scholarly journals Development of a Microwave Irradiation Probe for a Cylindrical Applicator

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 143 ◽  
Author(s):  
Tomohiko Mitani ◽  
Ryo Nakajima ◽  
Naoki Shinohara ◽  
Yoshihiro Nozaki ◽  
Tsukasa Chikata ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Impedance Matching ◽  
Input Power ◽  
Ultrapure Water ◽  
Electromagnetic Simulations ◽  
Measurement Results ◽  
Naoh Solution ◽  
Microwave Power Source ◽  
Reflected Power ◽  
Microwave Probe

A microwave irradiation probe was newly developed for downsizing microwave applicators and the overall microwave heating apparatus. The key component of the proposed probe is a tapered section composed of polytetrafluoroethylene (PTFE) and alumina. Insertion of the tapered section between the input port and the applicator vessel realizes impedance matching to the microwave power source and reduces the reflected power from the applicator. The proposed microwave probe for a cylindrical applicator was designed using 3D electromagnetic simulations. The permittivity data of two liquid samples—ultrapure water and 2 M NaOH solution—were measured and taken into simulations. The conductivity of the NaOH solution was estimated from the measurement results. The measured reflection ratio of the fabricated applicator was in good accordance with the simulated one. The frequency ranges in which the measured reflection ratio was less than 10% were from 1.45 GHz to 2.7 GHz when using water and from 1.6 GHz to 2.7 GHz when using the NaOH solution as the sample. The heating rate of the applicator was roughly estimated as 63 to 69 K for a 5 min interval during the 2.45 GHz microwave irradiation at the input power of 100 W.

scholarly journals Recovery of chitin and chitosan from shrimp waste with microwave technique and versatile application

2019 ◽  
Vol 86 ◽  
Author(s):  
Vanessa Pimentel Santos ◽  
Patrícia Maia ◽  
Nathália de Sá Alencar ◽  
Laryssa Farias ◽  
Rosileide Fontenele Silva Andrade ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Particle Size ◽  
Microwave Irradiation ◽  
Shrimp Waste ◽  
Candida Sp ◽  
Naoh Solution ◽  
Chitin And Chitosan ◽  
Shrimp Wastes

ABSTRACT: In this study, chitin and chitosan were extracted from Litopenaeus vannamei waste using chemical and microwave methods. Shrimp waste was cleaned, dried and ground sieved to 16, 32 and 60 mesh, and the samples were depigmented, demineralized, and deproteinized. Then, the chitin was submitted to a deacetylation process by 45% NaOH solution under microwave irradiation at 600w, for intermittent 15 min or using 5 pulses of 5 minutes. The study showed that the effectiveness of the particle size of 32 mesh and 6 pulses of 5 min to deacetylation with 92% of degree and chitosan yield (52.2%). The polymer chitosan showed higher antimicrobial activity against to Staphylococcus aureus, Escherichia coli, Salmonella enterica and the yeast Candida sp., respectively. The results indicated the feasibility of the microwave radiation as an attractive method to recover chitin and chitosan from shrimp wastes.

Vilyui-Markha interfluve of Yakutia: a region prospective for Cu-Ni-PGM mineralization

2021 ◽  
pp. 51-64
Author(s):  
P. IGNATOV ◽  
A. TOLSTOV ◽  
A. KOLESNIK ◽  
E. PROTSENKO ◽  
M. MALTSEV
Keyword(s):  
Siberian Platform ◽  
Basaltic Magma ◽  
Impact Zone ◽  
Activation Domain ◽  
Similar Composition ◽  
Geochemical Anomalies ◽  
Composition And Structure ◽  
Ore District

Materials are discussed on geologically similar structure of Norilsk ore district (NOD) and Vilyui-Markha interstream area (VMIA), which implies the latter prospects for Cu-Ni-PGM mineralization. Data is provided on Cu-Ni-Co-Zn mineral occurrences within Ygyattinsky diamondiferous region centered on VMIA. Geological similarities of NOD and VMIA are summarized below. Both regions are located in Mesozoic tectonomagmatic activation domain at the edge of large troughs: NOD is localized in the Siberian platform foredeep, and VMIA lies at Vilyui syneclise margin. NOD deposits are hosted by centroclines of large brachysynclines at slopes of Pyasinskoye dome. Within VMIA, prospects are located at Syuldyukarskoye dome slopes in margibal parts of large troughs. NOD and VMIA comprise Paleozoic marl-carbonate strata overlain by carbonaceous Carboniferous-Permian overburden, which could be assimilated by basaltic magma in Mesozoic contributing to its ore differentiation. Norilsk-Kharaelakh ore-bearing intrusion in VMIA appears to be similar to Kholomolokh sulfide-rich intrusion with its inferred extensive ore-bearing sills. They have similar composition and structure including presence of pegmatites. Ore-controlling Norilsk-Kharaelakh fault is believed to be simi- lar to Khatyryk-Kholomolokh fault, which was traced for 24 km by drilling and is one of sutures within deep-seated kimberlite-controlling Vilyui-Markha zone. This fault’s impact zone host concentrated geochemical anomalies and Cu-Ni-Co-Zn-Pt-Au-Ag Khomustakh occurrence. Based on this, Norilsk-type Cu-Ni prospects ranked as a potential ore cluster and three ore fields were identified

Microstructure and Properties of C-S-H/PCE Nanocomposites

2017 ◽  
Vol 898 ◽  
pp. 2089-2094
Author(s):  
He Qing Shen ◽  
Zi Ming Wang ◽  
Xiao Liu ◽  
Xiao Fan Pang ◽  
Long Xue
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Calcium Silicate ◽  
Structural Investigation ◽  
X Ray Diffraction ◽  
Enhancing Effect ◽  
X Ray ◽  
Microstructure And Properties ◽  
Composition And Structure ◽  
Early Strength

Different dosage of TPEG-polycarboxylate (PCE) copolymers were used to prepare the calcium-silicate hydrated (C-S-H)/PCE nanocomposites by precipitating C-S-H from Na2SiO3·9H2O and Ca (NO3)2·4H2O in the PCE solution. The composition and structure of the prepared C-S-H/PCE nanocomposites were characterized by XRD, SEM, FTIR methods, and the early strength of mortars was measured. The results show that structural investigation of the C-S-H/PCE nanocomposites via X-ray diffraction revealed a semi-crystalline composition, and the PCE polymers were adhered the surface of C-S-H particles in the composite. The preparation of C-S-H /PCE nanocomposites enhanced markedly the early strength of mortar, and when the dosage of PCE copolymers was up to 30%, the early strength enhancing effect was the highest, the early flexural strength increased up to 100%, and early compressive strength increased up to 120%. Therefore, C-S-H /PCE nanocomposites can improve the early strength of mortar effectively since it can lower the barrier of nucleation of the products, promote the nucleation and inhibit the growth of large grains effectively.

scholarly journals In Situ Preparation and Corrosion Resistance of a ZrO2 Film on a ZrB2 Ceramic

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 455 ◽  
Author(s):  
Haitao Yang ◽  
Jian Zhang ◽  
Junguo Li ◽  
Qiang Shen ◽  
Lianmeng Zhang
Keyword(s):  
Corrosion Resistance ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Alkaline Solutions ◽  
Hydrogen Electrode ◽  
In Situ Preparation ◽  
Composition And Structure ◽  
Naoh Solution ◽  
Order Of Magnitude

ZrO2 films were in situ prepared using the anodic passivation of a ZrB2 ceramic in alkaline solutions. The composition and structure of the films were characterized using field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The corrosion resistances were evaluated in 0.1 M oxalate solution using the potentiodynamic polarization method (PDP) and the electrochemical impedance spectroscopy (EIS) technique. The results show that ZrO2 films can be prepared using anodization from −0.8 to 0.8 V standard hydrogen electrode (SHE) in 2–16 M NaOH solutions. During the anodization, the dehydration reaction of Zr(OH)4 to ZrO2 caused the volume shrinkage and tensile stress of the films. When the thickness of the films exceeded a critical value, the mud-cracking morphology occurred. The films without cracks exhibited the inhibition effect and provided effective corrosion protection in a 0.1 M H2C2O4 solution, which had a positive correlation with the film thickness. The film obtained when put in an 8 M NaOH solution (near the critical thickness) was found to significantly improve its corrosion resistance when put in a 0.1 M H2C2O4 solution by almost one order of magnitude compared with the bare ceramic.

The reaction engineering of the anionic polymerization of isoprene

1993 ◽  
Vol 47 (9) ◽  
pp. 1589-1599 ◽  
Author(s):  
C. C. Chang ◽  
A. F. Halasa ◽  
J. W. Miller
Keyword(s):  
Anionic Polymerization ◽  
Reaction Engineering

Mastication. V. Separation and Structural Investigation of Natural Rubber-Polymethyl Methacrylate Interpolymers Formed by Mastication

1958 ◽  
Vol 31 (1) ◽  
pp. 58-72
Author(s):  
D. J. Angier ◽  
W. F. Watson
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Polymethyl Methacrylate ◽  
Structural Investigation ◽  
Extraction Methods ◽  
Fractional Precipitation ◽  
Block Polymer ◽  
Gel Effect ◽  
Profound Influence ◽  
Composition And Structure

Abstract Polymerization of methyl methacrylate admixed with natural rubber occurs on rupture of rubber molecules to free radicals by applied shearing forces. The polymeric products after different conditions and extents of reaction have been separated into uncombincd rubber, two interpolymer fractions, and uncombined polymethyl methacrylate by fractional precipitation and extraction methods. The structure of the interpolymers has been investigated by measurement of composition and osmotic molecular weight, ozonolysis to degrade the rubber segments and isolation of the polymethyl methacrylate fragments, autoxidation of the rubber segments, and viscosity measurements on the uncombined rubber. The interpolymer is a linear block polymer containing one polymethyl methacrylate segment and of the order of one or two rubber segments per molecule. The Trommsdorff gel effect has a profound influence on the rate of formation, composition, and structure of the interpolymer.

Experimental Study of Chemo-Thermal Micromachining of Glass

2016 ◽  
Author(s):  
Arham Ali ◽  
Murali Sundaram
Keyword(s):  
Laser Beam ◽  
Thermal Ablation ◽  
Carbon Dioxide Laser ◽  
Aqueous Sodium Hydroxide ◽  
Chemical Degradation ◽  
Target Point ◽  
Micro Machining ◽  
Machined Surface ◽  
Laser Target ◽  
Naoh Solution

Chemo-thermal micro-machining is a hybrid method of micro fabrication achieved by integrating laser based thermal ablation and chemical etching. Material removal in this process involves focussing laser beam on a glass specimen submerged in aqueous sodium hydroxide (NaOH) solution that causes chemical degradation of glass along with thermal ablation at the laser target point. Though laser by itself is capable of machining numerous materials, it often causes micro fractures radially along the machined surface, especially when used on glass. In the proposed process, continuous waves of carbon dioxide laser (10.6 μm wavelength) with varying power are irradiated on the surface of borosilicate glass slide immersed in 1M NaOH solution for varying duration of exposure. This resulted in smaller hole diameter and better surface finish in the micro machining of glass, as compared to machining by laser beam alone.

scholarly journals Zinc Recovery from Steelmaking Dust by Hydrometallurgical Methods

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 547 ◽  
Author(s):  
Piotr Palimąka ◽  
Stanisław Pietrzyk ◽  
Michał Stępień ◽  
Katarzyna Ciećko ◽  
Ilona Nejman
Keyword(s):  
Solid Phase ◽  
Sodium Hydroxide Solution ◽  
Aqueous Sodium Hydroxide ◽  
Complete Recovery ◽  
Phase Ratio ◽  
Maximum Efficiency ◽  
Test Results ◽  
Zinc Recovery ◽  
Naoh Solution ◽  
Steelmaking Dust

Hydrometallurgical recovery of zinc from electric arc furnace dust was investigated on a laboratory scale, using aqueous sodium hydroxide solution as a leaching agent. Special attention was paid to the effect of NaOH concentration, temperature and liquid/solid phase ratio on the zinc leachability. It was found that all tested factors increased the leachability, with the maximum efficiency of 88% obtained in a 6 M NaOH solution at a temperature of 80 °C and the liquid/solid phase ratio of 40. The test results confirmed the high selectivity of the zinc leaching agent. In spite of this, complete recovery of zinc from steelmaking dust has proved to be very difficult due to the occurrence of this element in the form of stable and sparingly soluble ZnFe2O4 ferrite. Purification of the solution by cementation and electrolysis gave zinc of purity 99.88% in powder form.

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