Preparation of Asymmetric Thermosensitive Double-layer Gel

2008 ◽  
Vol 1129 ◽  
Author(s):  
Takashi Iizawa ◽  
Akihiro Terao
Keyword(s):  
Acrylic Acid ◽  
Double Layer ◽  
Axial Symmetry ◽  
Core Shell ◽  
Synthetic Method ◽  
Shell Layer ◽  
New Approach ◽  
The Core ◽  
Shell Type ◽  
Acid Gel

AbstractHeterogeneous amidation of poly(acrylic acid) gel-1,8-diazabicyclo-[5,4,0]-7-undecene salt (DAA) in N-methyl-2-pyrrolidone containing an excess of alkylamine and triphenylphosphite occurred from the surface to give the corresponding DAA-poly(N-alkylacrylamide) (PNAA) core-shell type gel, consisting of an unreacted DAA core and a quantitatively amidated shell layer. Further amidation of the DAA-PNAA core-shell type gel with a second alkylamine afforded a novel core-shell type gel consisting of two PNAA layers: PNAA(2) and PNAA(1). The resulting cylindrical PNAA(2)-PNAA(1) core-shell type gels were resistant to marked deformation caused by swelling/de-swelling because of their axial symmetry. This paper proposes a new approach to the preparation of asymmetric thermosensitive PNAA(2)-PNAA(1) double-layer gels by several procedures using the synthetic method of the core-shell type gels containing of poly(N-isopropylacrylamide) and poly(N-n-propylacrylamide) layers. Among the obtained asymmetric double-layer gels the model I type gel (cylindrical grooved PNNPA-PNIPA core-shell type gel) was markedly bent in water at temperatures between the lower critical solution temperatures of both layers.

scholarly journals Synthesis of Poly(N-isopropylacrylamide) Gel and Core-Shell Type Gel with Thermo-Sensitive Shell Layer by Amidation of Poly(acrylic acid) Gel

2002 ◽  
Vol 34 (2) ◽  
pp. 63-71 ◽  
Author(s):  
Takashi Iizawa ◽  
Naoki Matsuno ◽  
Masashi Takeuchi ◽  
Fumihiko Matsuda
Keyword(s):  
Acrylic Acid ◽  
Core Shell ◽  
Shell Layer ◽  
Shell Type ◽  
Acid Gel ◽  
Poly Acrylic Acid

scholarly journals Microstructure and Magnetic Properties of NdFeB Sintered Magnets Diffusion-Treated with Cu/Al Mixed Dyco Alloy-Powder

2017 ◽  
Vol 62 (2) ◽  
pp. 1263-1266 ◽  
Author(s):  
M.-W. Lee ◽  
K.-H. Bae ◽  
S.-R. Lee ◽  
H.-J. Kim ◽  
T.-S. Jang
Keyword(s):  
Grain Boundary ◽  
Diffusion Path ◽  
Boundary Phase ◽  
Core Shell ◽  
Phase Layer ◽  
Sintered Magnets ◽  
The Core ◽  
Shell Type ◽  
Property Changes ◽  
And Diffusion

AbstractWe investigated the microstructural and magnetic property changes of DyCo, Cu + DyCo, and Al + DyCo diffusion-treated NdFeB sintered magnets. The coercivity of all diffusion treated magnet was increased at 880ºC of 1stpost annealing(PA), by 6.1 kOe in Cu and 7.0 kOe in Al mixed DyCo coated magnets, whereas this increment was found to be relatively low (3.9 kOe) in the magnet coated with DyCo only. The diffusivity and diffusion depth of Dy were increased in those magnets which were treated with Cu or Al mixed DyCo, mainly due to comparatively easy diffusion path provided by Cu and Al because of their solubility with Ndrich grain boundary phase. The formation of Cu/Al-rich grain boundary phase might have enhanced the diffusivity of Dy-atoms. Moreover, relatively a large number of Dy atoms reached into the magnet and mostly segregated at the interface of Nd2Fe14B and grain boundary phases covering Nd2Fe14B grains so that the core-shell type structures were developed. The formation of highly anisotropic (Nd, Dy)2Fe14B phase layer, which acted as the shell in the core-shell type structure so as to prevent the reverse domain movement, was the cause of enhancing the coercivity of diffusion treated NdFeB magnets. Segregation of cobalt in Nd-rich TJP followed by the formation of Co-rich phase was beneficial for the coercivity enhancement, resulting in the stabilization of the metastable c-Nd2O3phase.

Microwave absorption properties of the core/shell-type iron and nickel nanoparticles

2008 ◽  
Vol 320 (6) ◽  
pp. 1106-1111 ◽  
Author(s):  
B. Lu ◽  
X.L. Dong ◽  
H. Huang ◽  
X.F. Zhang ◽  
X.G. Zhu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Nickel Nanoparticles ◽  
Core Shell ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
The Core ◽  
Shell Type

Li-insertion Behavior in NanocrystallineTiO2-(MoO3)z Core-Shell Materials

2000 ◽  
Vol 658 ◽  
Author(s):  
Gregory J. Moore ◽  
Dominique Guyomard ◽  
Scott H. Elder
Keyword(s):  
Transition Metal ◽  
Surface Charge ◽  
Double Layer ◽  
Single Phase ◽  
Inductive Effect ◽  
Core Shell ◽  
Fundamental Study ◽  
The Core ◽  
Single Phase Material

ABSTRACTA fundamental study of the Li insertion behavior of a series of materials consisting of a TiO2 core having MoO3 on the surface has been carried out in order to determine the influence of the shell. These TiO2-(MoO3)z materials, where (z) denotes the fraction of coverage from a partial to a double layer, range in diameter from 40-100 Å. Calculations have been done on their theoretical lithium capacity using a maximum of Li0.5TiO2 for the core, and Li1.5MoO3 at the TiO2/MoO3 interface, and they have been compared to that found experimentally. The reversible Li-insertion capacity was shown to increase from 0.34 per Ti for the pure TiO2 sample, to 0.91 Li per transition metal when the MoO3 coverage increased to one monolayer. There was only one plateau observed in the electrochemical scans for the samples showing that they function as a single-phase material making them interesting for electrodes. The redox voltage of the TiO2/Li0.5TiO2 biphasic transformation increased 60 mV from the pure TiO2 to the sample containing one monolayer of MoO3. This effect was interpreted as due to a change in TiO2 surface charge coming from an inductive effect of Ti-O-Mo bonds.

Design of Core−Shell-Type Nanoparticles Carrying Stable Radicals in the Core

2009 ◽  
Vol 10 (3) ◽  
pp. 596-601 ◽  
Author(s):  
Toru Yoshitomi ◽  
Daisuke Miyamoto ◽  
Yukio Nagasaki
Keyword(s):  
Core Shell ◽  
The Core ◽  
Shell Type ◽  
Stable Radicals

Novel core-shell type thermo-sensitive nanoparticles composed of poly(γ-benzyl L-glutamate) as the core and poly(N-isopropylacrylamide) as the shell

1997 ◽  
Vol 18 (5) ◽  
pp. 361-369 ◽  
Author(s):  
Chong-Su Cho ◽  
Jae-Bok Cheon ◽  
Young-Il Jeong ◽  
In-Sook Kim ◽  
Sung-Ho Kim ◽  
...  
Keyword(s):  
Core Shell ◽  
The Core ◽  
Shell Type

Responsive properties of crystalline colloidal arrays formed by core-shell microspheres with pH and temperature sensitivities

2012 ◽  
Vol 90 (1) ◽  
pp. 131-137 ◽  
Author(s):  
Gwénaëlle Bazin ◽  
X.X. Zhu
Keyword(s):  
Acrylic Acid ◽  
Critical Concentration ◽  
Colloidal Crystals ◽  
Core Shell ◽  
Shell Layer ◽  
Polymeric Microspheres ◽  
Temperature Changes ◽  
Crystalline Colloidal Arrays ◽  
Colloidal Arrays ◽  
Stimuli Sensitive

Polymeric microspheres responsive to pH and temperature changes have been prepared by a two-step surfactant-free emulsion polymerization with a polystyrene core and a hydrogel shell. The double sensitivity is achieved by the copolymerization in the shell layer of acrylic acid and N-isopropylacrylamide, which are pH- and thermo-responsive, respectively. Above a certain critical concentration, these microspheres are able to self-assemble into crystalline colloidal arrays, causing intense visible light diffraction. The behavior of these structures has been studied and correlated to the properties of the microspheres. The packing of these microspheres results in stimuli-sensitive colloidal crystals, with a behavior directly linked to the interactions between the particles and the surrounding media.

Preparation and Application of a Leather Finish with Core-Shell Structure

2013 ◽  
Vol 791-793 ◽  
pp. 326-329 ◽  
Author(s):  
Xin Zhao ◽  
Yan Song Zhao
Keyword(s):  
Infrared Spectroscopy ◽  
Acrylic Acid ◽  
Methyl Methacrylate ◽  
Acrylic Resin ◽  
Core Shell ◽  
Coating Agent ◽  
The Core ◽  
Core Shell Structure ◽  
Finishing Agent ◽  
Leather Finishing

The core-shell acrylic resin emulsion is prepared by seed polymerization technology, with styrene, methyl methacrylate, acrylonitrile as monomer, butyl acrylate, methyl methacrylate, acrylic acid as shell monomer, and the of nanoTiO2 is introducted in shell emulsion. Infrared spectroscopy were used to characterize the structure of the prepared coating agent. The preparation of TiO2/acrylic resin emulsion for leather finishing agent, and discusses its influence on the leather properties. The results show that the synthetic finishing agents for dyeing after the fatliquoring leather finishing, good finishing effect can be obtained.

A Cd(OH)2/CdS heteronanostructure of the core-shell type

2008 ◽  
Vol 419 (1) ◽  
pp. 41-46 ◽  
Author(s):  
A. S. Vorokh ◽  
N. S. Kozhevnikova
Keyword(s):  
Core Shell ◽  
The Core ◽  
Shell Type
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