Influence of metal ions on the alkali-swelling behavior of carboxylated acrylic polymer latexes

H. Wiese; R. Rupaner

doi:10.1007/s003960050394

Predicting the Swelling Behavior of Acrylic Superabsorbent Polymers Used in Diapers

Advances in Polymer Technology ◽

10.1155/2021/9999826 ◽

2021 ◽

Vol 2021 ◽

pp. 1-7

Author(s):

Shuxin Zhang ◽

Yangyang Peng ◽

Ran Jiang ◽

Wenqiang Liu ◽

Huanlei Yang ◽

...

Keyword(s):

Swelling Behavior ◽

Product Performance ◽

Individual Factors ◽

Semiempirical Model ◽

Practical Application ◽

Acrylic Polymer ◽

Superabsorbent Polymers ◽

Acrylic Polymers ◽

Nacl Concentration ◽

Higher Temperature

Acrylic polymer is a superabsorbent for water and widely used in diapers, in which its swelling behavior can be significantly affected by several factors, i.e., the time, temperature, pH, and salt concentration, and thus the product performance in the applications. In this work, the water absorption behavior of acrylic superabsorbent polymers by each of these individual factors was investigated. The results showed that the water absorbency increases with the pH in the range of 2 to ~7 and decreases when the pH continues to increase. However, it decreases with the increases in NaCl concentration in the solution. Moreover, more water can be absorbed by the acrylic polymers at the higher temperature. Based on a previously developed kinetic swelling model and the information from the above investigations, a semiempirical model for predicting the swelling behavior of superabsorbent polymers (SAPs) under different conditions has been developed. Data showed that the model can predict (with a relative error of <4.5%) the amount of water absorbed by acrylic SAPs under different swelling conditions. The model would be very helpful to the practical application in both product design and its performance evaluation.

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HREM Study of electron-induced surface radiation damage in ReO3

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087495 ◽

1991 ◽

Vol 49 ◽

pp. 636-637

Author(s):

R. Ai ◽

H.-J. Fan ◽

L. D. Marks

Keyword(s):

Transition Metal ◽

Metal Ions ◽

Metal Oxides ◽

Electron Irradiation ◽

Transition Metal Oxides ◽

Carbon Film ◽

Transition Metal Ions ◽

Surface Radiation ◽

Valence Transition ◽

Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

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ELNES of Iron Compounds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133734 ◽

1990 ◽

Vol 48 (2) ◽

pp. 28-29

Author(s):

Hiroki Kurata ◽

Kazuhiro Nagai ◽

Seiji Isoda ◽

Takashi Kobayashi

Keyword(s):

Energy Loss ◽

Metal Ions ◽

Energy Resolution ◽

Transition Metal Oxides ◽

Local Symmetry ◽

Iron Compounds ◽

Fine Structures ◽

Electron Energy Loss ◽

Fe Ions ◽

Electron Energy Loss Spectra

Electron energy loss spectra of transition metal oxides, which show various fine structures in inner shell edges, have been extensively studied. These structures and their positions are related to the oxidation state of metal ions. In this sence an influence of anions coordinated with the metal ions is very interesting. In the present work, we have investigated the energy loss near-edge structures (ELNES) of some iron compounds, i.e. oxides, chlorides, fluorides and potassium cyanides. In these compounds, Fe ions (Fe2+ or Fe3+) are octahedrally surrounded by six ligand anions and this means that the local symmetry around each iron is almost isotropic.EELS spectra were obtained using a JEM-2000FX with a Gatan Model-666 PEELS. The energy resolution was about leV which was mainly due to the energy spread of LaB6 -filament. The threshole energies of each edges were measured using a voltage scan module which was calibrated by setting the Ni L3 peak in NiO to an energy value of 853 eV.

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