scholarly journals Synthesis and Control of the Shell Thickness of Polyaniline and Polypyrrole Half Hollow Spheres Using the Polystyrene Cores

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Su-Ryeon Yun ◽  
Gyeong-Ok Kim ◽  
Chan Woo Lee ◽  
Nam-Ju Jo ◽  
Yongku Kang ◽  
...  
Keyword(s):  
Shell Thickness ◽  
Hollow Spheres ◽  
Core Shell ◽  
Chemical Structures ◽  
The Core ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Core Shell Structure ◽  
And Control ◽  
Ft Ir Spectroscopy

Polyaniline (Pani) and polypyrrole (Ppy) half hollow spheres with different shell thicknesses were successfully synthesized by three steps process using polystyrene (PS) as the core. The PS core was synthesized by emulsion polymerization. Aniline and pyrrole monomers were polymerized on the surface of the PS core. The shells of Pani and Ppy were fabricated by adding different amounts of aniline and pyrrole monomers. PS cores were dissolved and removed from the core shell structure by solvent extraction. The thicknesses of the Pani and Ppy half hollow spheres were observed by FE-SEM and FE-TEM. The chemical structures of the Pani and Ppy half hollow spheres were characterized by FT-IR spectroscopy and UV-Vis spectroscopy. The shell thicknesses of the Pani half hollow spheres were 30.2, 38.0, 42.2, 48.2, and 52.4 nm, while the shell thicknesses of the Ppy half hollow spheres were 16.0, 22.0, 27.0, and 34.0 nm. The shell thicknesses of Pani and Ppy half hollow spheres linearly increased as the amount of the monomer increased. Therefore, the shell thickness of the Pani and Ppy half hollow spheres can be controlled in these ranges.

scholarly journals Stress Distribution in Microregion of Core–Shell Structure Lightweight Aggregate Concrete

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 540
Author(s):  
Meng Zhu ◽  
Lihua Zhang ◽  
Weilong Wang ◽  
Hongping Zhang ◽  
Wenjin Xing
Keyword(s):  
Stress Distribution ◽  
Shell Structure ◽  
Shell Thickness ◽  
Lightweight Aggregate ◽  
Thickness Ratio ◽  
Core Shell ◽  
Distribution Analysis ◽  
Failure Resistance ◽  
The Core ◽  
Core Shell Structure

An in-depth understanding of the effect of cordierite/belite core–shell structure lightweight aggregate (CSLWA) on the mechanical performance of LWA concrete (LWAC) is critical for improving the failure resistance of LWAC. In this study, the stress distribution of the microregion in CSLWA was systematically investigated via a finite element analysis to explore its effect on the mechanical properties of LWAC. In detail, the material components, core–shell thickness ratio, porosity and width of interfacial transition zone (ITZ), and absence or presence of interfacial bonding zone (IBZ) were considered during the stress distribution analysis of the microregion of LWAC. The results showed that a reduction in the material components, with a high-elastic modulus in the core, a decrease in the core–shell thickness ratio, and the formation of the core–shell IBZ are beneficial for optimizing the stress distribution of the microregion and alleviating the stress concentration phenomenon of LWAC. Moreover, due to the continuous hydration of belite shell, the ITZ of CSLWA becomes increasingly dense, thus the stress distribution is more uniform than that of ordinary LWAC, indicating that CSLWA exhibits the potential to improve the failure resistance of LWAC. This study helps to develop an understanding of the role played by the core–shell structure in improving the toughness of LWAC, and provides a new solution and methodology for improving the brittleness of LWAC.

Synthesis of polyaniline/TiO2 nanocomposites with metalloporphyrin and metallophthalocyanine catalysts

2009 ◽  
Vol 13 (08n09) ◽  
pp. 980-985 ◽  
Author(s):  
Mohammad Reza Nabid ◽  
Roya Sedghi ◽  
Abdolmajid Bayandori Moghaddam ◽  
Mohammad Barari ◽  
Parisa R. Jamaat ◽  
...  
Keyword(s):  
Oxidative Polymerization ◽  
Inorganic Nanoparticles ◽  
Cathodic Peak ◽  
The Core ◽  
Tetraphenyl Porphyrin ◽  
Ft Ir ◽  
Core Shell Structure ◽  
Tga Analysis ◽  
Ft Ir Spectroscopy ◽  
Aniline Polymerization

Inorganic nanoparticles combined with conducting polymers provide interesting physical properties. This research describes the aniline polymerization taking place on the nanoparticles surface by catalytic oxidative polymerization with metalloporphyrin and metallophthalocyanine. In this way, the core-shell structure of the polyaniline/ TiO2 nanocomposites was obtained. The comparison of results demonstrates that porphyrin is a better catalyst than phthalocyanine for synthesis of nanocomposite. The morphology and composition of the nanocomposites were characterized by techniques such as SEM and FT-IR spectroscopy. TGA analysis showed that the nanocomposites, synthesized with iron(III) tetrasulfonated tetraphenyl porphyrin and iron(II) tetrasulfonated phthalocyanines, contained 10% and 5% conducting polyaniline (by mass), respectively. Eventually, the voltammograms revealed that these nanocomposites were electroactive and there was a linear relationship between the anodic and cathodic peak current values and scan rates.

Preparation and Characterization of SiO2-PMMA with Different Shell Thickness Using AGET ATRP

2013 ◽  
Vol 634-638 ◽  
pp. 1951-1954 ◽  
Author(s):  
Lei Zhang ◽  
Guo Wei Zhou ◽  
Min Nan Zhao
Keyword(s):  
Electron Transfer ◽  
1H Nmr ◽  
Shell Thickness ◽  
Silica Surface ◽  
Core Shell ◽  
Aget Atrp ◽  
The Core ◽  
Ft Ir ◽  
Shell Composite

Monodispersed SiO2-core/PMMA-shell composite nanospheres have been prepared via activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) mediated by an iron (III) catalyst. By simply adjusting the amount of monomer, the shell thickness of products can easily be tuned. Samples were characterized by FT-IR, TEM, 1H NMR. The results showed that the sphere structure kept unchanging after grafting. FT-IR and 1H NMR measurements show that the polymer was grafted on the silica surface successfully. TEM results for composite nanospheres suggested the core-shell-like structure of the hybrid nanoparticle.

scholarly journals Control of Spectral Shift of Plasmon Resonance of Ag-PVP Nanocomposite By Varying The PVP Shell Thickness In Core-Shell Structure

2021 ◽  
Author(s):  
Dilip Sao ◽  
Probodh Kumar Kuiri ◽  
Rajib Nath
Keyword(s):  
Plasmon Resonance ◽  
Shell Structure ◽  
Crucial Role ◽  
Shell Thickness ◽  
Synthesis Process ◽  
Core Shell ◽  
Ag Nps ◽  
The Core ◽  
Core Shell Structure

Abstract Metal-polymer nanocomposite materials have interesting physical, chemical, and optical properties which were highly utilized in electronic, optical,and biomedical applications. Here, we have experimentally and theoretically studied the crucial role of polymer Polyvinylpyrrolidone (PVP) on the localized surface plasmon resonance (LSPR) spectra of silver (Ag) nanoparticles (NPs). In this work, we have synthesized PVP stabilized Ag NPs in Ethelene Glycol (EG) medium and observed a large blueshift (20 nm)of LSPR peak and tunable plasmonic properties of PVP coated Ag NPs by only varying the concentration of PVP. A reduction of Ag NP size from 13 nm to 5 nm with the increase in PVP concentration from 0.125 mM to 3 mM is seen. We found that the observed large blueshift of the LSPR bands with the varying in PVP concentration is not just due to the reduced Ag NP size but due to the combined effect of thickness of the PVP shell and radius of the Ag NP core. The polymer PVP used in the synthesis process of Ag NPs plays role of a surface modifier and forms a protective shell/layer surrounding the (core) particle. This is supported by the theoretical optical absorption data obtained from a modified effective medium theory. To accommodate such a large blueshift of the LSPR bands we have considered the Ag-PVP core-shell structure. The LSPR peak shift in the core-shell nanostructure is well accommodated by varying the effective shell thickness of PVP while taking the core size of Ag NPs as measured experimentally for each case. This clearly indicates that the observed large blueshift of SPR band of Ag NPs cannot be justified by considering the decrease in Ag NP size alone. It is also confirmed that the shell thickness of PVP plays a crucial role in explaining the blueshift of the SPR band of Ag NPs. This study can help to understand the optical response especially plasmonic properties of other metal NPs coated with organic polymers.

The Preparation of Core-Shell Type Acrylic-Polyurethane Composite Emulsions for Pigment Printing

2011 ◽  
Vol 332-334 ◽  
pp. 387-390
Author(s):  
Chun Lei Xu ◽  
Yi Hu ◽  
Jin Qiang Liu ◽  
Sheng Peng Wang ◽  
Shao Min Qu ◽  
...  
Keyword(s):  
Shell Structure ◽  
Core Shell ◽  
Seeded Emulsion Polymerization ◽  
Acrylic Polymer ◽  
The Core ◽  
Polyurethane Composite ◽  
Transmission Electron ◽  
Ft Ir ◽  
Core Shell Structure ◽  
Acrylic Polyurethane

Vinyl-endblocked polyurethanes were prepared from polyether diols(N210), isophorone diisocyanate (IPDI), dimethylol propionic acid (DMPA) and 2-hydroxyethyl acrylate (HEA). The core-shell structure acrylic-polyurethane composite emulsion was prepared by seeded emulsion polymerization of methyl methacrylate (MMA) and butyl acrylate (BA) using the polyurethanes emulsions as seeded emulsions. The core and shell regions were occupied by acrylic polymer and polyurethane, respectively. Because polyurethanes were vinyl-endblocked, acrylic monomers could graft partially to them. The formation of core-shell structure was observed by transmission electron microscopy (TEM). The structure and properties of dried film were studied by Fourier-transform infrared spectroscopy (FT-IR) and TGA.

scholarly journals The Preparation, Thermal Properties, and Fire Property of a Phosphorus-Containing Flame-Retardant Styrene Copolymer

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 127 ◽  
Author(s):  
Yu Sun ◽  
Yazhen Wang ◽  
Li Liu ◽  
Tianyuan Xiao
Keyword(s):  
Thermal Properties ◽  
Thermogravimetric Analysis ◽  
Flame Retardant ◽  
Oxygen Index ◽  
Limiting Oxygen Index ◽  
Chemical Structures ◽  
1H Nuclear Magnetic Resonance ◽  
Phosphorus Containing ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

A 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) acrylate, (6-oxidodibenzo [c,e][1,2] oxaphosphinin-6-yl) methyl acrylate (DOPOAA), has been prepared. Copolymers of styrene (St) and DOPOAA were prepared by emulsion polymerization. The chemical structures of copolymers containing levels of DOPOAA were verified using Fourier transform infrared (FT-IR) spectroscopy and 1H nuclear magnetic resonance (1H-NMR) spectroscopy. The thermal properties and flame-retardant behaviors of DOPO-containing monomers and copolymers were observed using thermogravimetric analysis and micro calorimetry tests. From thermogravimetric analysis (TGA), it was found out that the T5% for decomposition of the copolymer was lower than that of polystyrene (PS), but the residue at 700 °C was higher than that of PS. The results from micro calorimetry (MCC) tests indicated that the rate for the heat release of the copolymer combustion was lower than that for PS. The limiting oxygen index (LOI) for combustion of the copolymer rose with increasing levels of DOPOAA. These data indicate that copolymerization of the phosphorus-containing flame-retardant monomer, DOPOAA, into a PS segment can effectively improve the thermal stability and flame retardancy of the copolymer.

scholarly journals A SERS Study of Charge Transfer Process in Au Nanorod–MBA@Cu2O Assemblies: Effect of Length to Diameter Ratio of Au Nanorods

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 867
Author(s):  
Lin Guo ◽  
Zhu Mao ◽  
Sila Jin ◽  
Lin Zhu ◽  
Junqi Zhao ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Shell Structure ◽  
Shell Structures ◽  
Core Shell ◽  
Absorption Bands ◽  
Au Nanorods ◽  
The Core ◽  
Band Position ◽  
Surface Enhanced Raman ◽  
Core Shell Structure

Surface-enhanced Raman scattering (SERS) is a powerful tool in charge transfer (CT) process research. By analyzing the relative intensity of the characteristic bands in the bridging molecules, one can obtain detailed information about the CT between two materials. Herein, we synthesized a series of Au nanorods (NRs) with different length-to-diameter ratios (L/Ds) and used these Au NRs to prepare a series of core–shell structures with the same Cu2O thicknesses to form Au NR–4-mercaptobenzoic acid (MBA)@Cu2O core–shell structures. Surface plasmon resonance (SPR) absorption bands were adjusted by tuning the L/Ds of Au NR cores in these assemblies. SERS spectra of the core-shell structure were obtained under 633 and 785 nm laser excitations, and on the basis of the differences in the relative band strengths of these SERS spectra detected with the as-synthesized assemblies, we calculated the CT degree of the core–shell structure. We explored whether the Cu2O conduction band and valence band position and the SPR absorption band position together affect the CT process in the core–shell structure. In this work, we found that the specific surface area of the Au NRs could influence the CT process in Au NR–MBA@Cu2O core–shell structures, which has rarely been discussed before.

Construction of MOFs-Shell Porous Materials and Performance Study in Selective Adsorption and Separation of Benzene Pollutants

2021 ◽  
Author(s):  
Yu Qiao ◽  
Na Lv ◽  
Dong Li ◽  
Hongji Li ◽  
Xiangxin Xue ◽  
...  
Keyword(s):  
Porous Materials ◽  
Shell Structure ◽  
Selective Adsorption ◽  
Core Shell ◽  
Architecture Design ◽  
Performance Study ◽  
The Core ◽  
Core Shell Structure ◽  
And Performance ◽  
Sacrificial Agent

Metastable Cu2O is an attractive material for the architecture design of integrated nanomaterials. In this context, Cu2O was used as the sacrificial agent to form the core-shell structure of Cu2O@HKUST-1...

Optical Temperature Sensing of Core-Shell Structured NaYF4:Yb3+, Er3+@NaYF4 Nanocrystals with Different Shell Thickness

2015 ◽  
Vol 738-739 ◽  
pp. 27-30
Author(s):  
Dong Dong Li ◽  
Qi Yue Shao ◽  
Yan Dong ◽  
Jian Qing Jiang
Keyword(s):  
Shell Thickness ◽  
Thermal Sensitivity ◽  
Upconversion Luminescence ◽  
Temperature Sensing ◽  
Upconversion Nanoparticles ◽  
Core Shell ◽  
Sensing Properties ◽  
The Core ◽  
Β Phase ◽  
Biomedical Fields

Hexagonal (β)-phase NaYF4:Yb3+, Er3+ upconversion nanoparticles (UCNPs) with and without an inert (undoped NaYF4) shell have been successfully synthesized and the effects of shell thickness on the upconversion luminescence (UCL) and temperature sensing properties were systematically investigated. It was found that the NaYF4 shell and its thickness do not affect the RHS values and thermal sensitivity, but can obviously improve the UCL intensity of NaYF4:Yb3+, Er3+ UCNPs. It implies that the core-shell structured NaYF4:Yb3+, Er3+@NaYF4 UCNPs with excellent UCL properties have great potential to be used as temperature sensing probes in biomedical fields, without considering the influences of the shell thickness on their temperature sensing properties.

Assessing molecular similarity/diversity of chemical structures by FT-IR spectroscopy

2001 ◽  
Vol 24 (4) ◽  
pp. 613-627 ◽  
Author(s):  
V. Schoonjans ◽  
F. Questier ◽  
Q. Guo ◽  
Y. Van der Heyden ◽  
D.L. Massart
Keyword(s):  
Ir Spectroscopy ◽  
Molecular Similarity ◽  
Chemical Structures ◽  
Ft Ir ◽  
Ft Ir Spectroscopy
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