Control of crystal polymorphs by a ‘latent inductor’: crystallization of calcium carbonate in conjunction with in situ radical polymerization of sodium acrylate in aqueous solution

2000 ◽  
pp. 1537-1538 ◽  
Author(s):  
Kensuke Naka ◽  
Dong-Ki Keum ◽  
Yasuyuki Tanaka ◽  
Yoshiki Chujo
Keyword(s):  
Aqueous Solution ◽  
Calcium Carbonate ◽  
Radical Polymerization ◽  
Sodium Acrylate

scholarly journals Aqueous copper(0) mediated reversible deactivation radical polymerization of 2-hydroxyethyl acrylate

2015 ◽  
Vol 6 (36) ◽  
pp. 6509-6518 ◽  
Author(s):  
Mingmin Zhang ◽  
Michael F. Cunningham ◽  
Robin A. Hutchinson
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Radical Polymerization ◽  
Reversible Deactivation ◽  
Reversible Deactivation Radical Polymerization

Lowering the concentration of adsorbed radicals on the Cu(0) surface, achieved by reducing catalyst and adding NaBr, is the key to the synthesis of well-defined P(HEA) without a high molecular weight shoulder in aqueous solution using two-step Cu(0)in situmediation.

Biomimetic Synthesis of Hydrophobic Calcium Carbonate Nanoparticles In Situ

2010 ◽  
Vol 113-116 ◽  
pp. 807-810
Author(s):  
Yang Xu ◽  
Cheng Yu Wang ◽  
Jian Li
Keyword(s):  
Aqueous Solution ◽  
Contact Angle ◽  
Calcium Carbonate ◽  
Nucleation And Growth ◽  
Organic Substrate ◽  
Biomimetic Synthesis ◽  
Dodecanoic Acid ◽  
Caco3 Nanoparticles ◽  
Surface Modified

The hydrophobic CaCO3 nanoparticles were synthesized in situ by mimicking the essential functions of biomineralization. Using this method, CaCO3 nanoparticles were synthesized and were surface modified at the same time in the system of aqueous solution. The organic substrate of dodecanoic acid used here not only induces the nucleation and growth of calcium carbonate but also make the surface of calcium carbonate hydrophobic. The contact angle of the modified CaCO3 nanoparticles reached 110o.

A TEM study of the microstructure of avian eggshells

1992 ◽  
Vol 50 (2) ◽  
pp. 1102-1103
Author(s):  
S. Q. Xiao ◽  
S. Baden ◽  
A. H. Heuer
Keyword(s):  
Electron Microscope ◽  
Calcium Carbonate ◽  
Nucleation And Growth ◽  
Growth Mechanisms ◽  
Shell Surface ◽  
Thin Sections ◽  
Polycrystalline Metals ◽  
Transmission Electron ◽  
Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

scholarly journals Effect of Na- and Organo-Modified Montmorillonite/Essential Oil Nanohybrids on the Kinetics of the In Situ Radical Polymerization of Styrene

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 474
Author(s):  
Ioannis S. Tsagkalias ◽  
Alexandra Loukidi ◽  
Stella Chatzimichailidou ◽  
Constantinos E. Salmas ◽  
Aris E. Giannakas ◽  
...  
Keyword(s):  
Essential Oil ◽  
Radical Polymerization ◽  
Food Packaging ◽  
In Situ Polymerization ◽  
Average Molecular Weight ◽  
Monomer Conversion ◽  
Hydroxyl Groups ◽  
Modified Montmorillonite ◽  
Kinetics Of

The great concern about the use of hazardous additives in food packaging materials has shown the way to new bio-based materials, such as nanoclays incorporating bioactive essential oils (EO). One of the still unresolved issues is the proper incorporation of these materials into a polymeric matrix. The in situ polymerization seems to be a promising technique, not requiring high temperatures or toxic solvents. Therefore, in this study, the bulk radical polymerization of styrene was investigated in the presence of sodium montmorillonite (NaMMT) and organo-modified montmorillonite (orgMMT) including thyme (TO), oregano (OO), and basil (BO) essential oil. It was found that the hydroxyl groups present in the main ingredients of TO and OO may participate in side retardation reactions leading to lower polymerization rates (measured gravimetrically by the variation of monomer conversion with time) accompanied by higher polymer average molecular weight (measured via GPC). The use of BO did not seem to affect significantly the polymerization kinetics and polymer MWD. These results were verified from independent experiments using model compounds, thymol, carvacrol and estragol instead of the clays. Partially intercalated structures were revealed from XRD scans. The glass transition temperature (from DSC) and the thermal stability (from TGA) of the nanocomposites formed were slightly increased from 95 to 98 °C and from 435 to 445 °C, respectively. Finally, better dispersion was observed when orgMMT was added instead of NaMMT.

Comment on ‘‘In situ photoluminescence spectral study of porous Si in HF aqueous solution’’ [Appl. Phys. Lett. 65, 1653 (1994)]

1995 ◽  
Vol 66 (21) ◽  
pp. 2912-2913 ◽  
Author(s):  
M. Davison ◽  
K. P. O’Donnell ◽  
U. M. Noor ◽  
D. Uttamchandani ◽  
L. E. A. Berlouis
Keyword(s):  
Aqueous Solution ◽  
Spectral Study ◽  
Porous Si

scholarly journals Radiation-initiated high strength chitosan/lithium sulfonate double network hydrogel/aerogel with porosity and stability for efficient CO2 capture

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20486-20497
Author(s):  
Zhiyan Liu ◽  
Rui Ma ◽  
Wenjie Du ◽  
Gang Yang ◽  
Tao Chen
Keyword(s):  
Aqueous Solution ◽  
High Strength ◽  
Beam Radiation ◽  
Chitosan Hydrogel ◽  
Double Network ◽  
Electron Beam Radiation ◽  
Freeze Dried ◽  
Urea Aqueous Solution ◽  
Capture Capacity

Chitosan hydrogel is regenerated from alkali/urea aqueous solution and the lithium sulfonate second network is introduced by electron beam radiation-initiated in situ free radical polymerization. The freeze-dried aerogel has CO2 capture capacity.

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