Raman spectroscopic study of hydrogen bonding in aqueous carboxylic acid solutions. 3. Polyacrylic acid

Tanaka, Naoki; Kitano, Hiromi; Ise, Norio

doi:10.1021/ma00010a060

Cited by 46 publications

(41 citation statements)

References 9 publications

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“…38 Tanaka et al showed the presence of dimer, resolved the dimer from monomer in solution, and suggested that a "cooperative" H-bonding may form in a Poly-A aqueous solution that may explain the observed behavior in the Raman spectra. 39 In contrast to our Raman results, NMR analysis shows no difference between the spectra of solid and liquid samples of Poly-A. Figure 17 illustrates a set of surprising results wherein the chelation values for calcium, after dissolving the dry sample of Poly-A in water, are lower than those observed in the original sample prepared in water.…”

Section: Further Characterization Of Poly-acontrasting

confidence: 70%

Polyacrylic acid (poly-A) as a chelant and dispersant

Kuila¹,

Blay²,

Borjas³

et al. 1999

J. Appl. Polym. Sci.

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Polyacrylic acid was synthesized in water by persulfate-initiated polymerization (solution polymerization) of glacial acrylic acid in the absence of a chain-transfer agent. The final product is odorless and colorless. Chelation for calcium ions using a calcium electrode show that our poly(acrylic acid) has a higher chelation capacity than that of existing commercial poly(acrylic acids). A design of experiments was performed to optimize the synthesis conditions to obtain poly(acrylic acid) with a high maximum chelation value. These studies also helped us to gain insight into its high chelation capacity. The chelation capacity for calcium reaches its highest values when polymerization near isothermal conditions is done ϳ 95°C with an acrylic acid concentration of Յ21 wt % and an addition time Ͼ1 h. These conditions favor higher molecular weight poly(acrylic acid) with a polydispersity ϳ 4. The dispersion properties of our poly(acrylic acid) are similar to those of the commercial ones. This dual capability of chelation and dispersion is absent in commercial chelants such as ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and their analogs. At pH Ͼ 7, chelation of calcium by our poly(acrylic acid) is much higher than that observed with EDTA. Characterization by NMR, Raman, FTIR, and molecular modeling are included in an attempt to understand structural features that can explain the higher chelation capacity of our atactic poly(acrylic acid).

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Section: Further Characterization Of Poly-acontrasting

confidence: 70%

Polyacrylic acid (poly-A) as a chelant and dispersant

Kuila¹,

Blay²,

Borjas³

et al. 1999

J. Appl. Polym. Sci.

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“…However, PAA chains are known to form inter-and intramolecular hydrogen bonds that act as stickers and enhance the dissipation involved in pulling out the entanglements. [10] Thus, the solution transforms into a tough solid gel. The MMS was made from a mixture of styrene, butyl acrylate, and acrylic acid (AA).…”

Section: When the Mms Emulsion Is Irradiated With 60mentioning

confidence: 99%

A Novel Hydrogel with High Mechanical Strength: A Macromolecular Microsphere Composite Hydrogel

et al. 2007

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The industrial and biomedical applications of hydrogels made from either natural or synthetic sources are strongly limited by their poor mechanical properties. A normal structure (NS) hydrogel breaks under low stress because there are very few energy dissipation mechanisms to slow crack propagation. In addition, as their crosslinking points are distributed irregularly and the polymer chains between the crosslinking points have different lengths, the stress cannot be evenly distributed between the polymer chains, and crack initiation is facile. Many efforts have been focused on increasing the mechanical strength of hydrogels, [1] but the robustness still remains unsatisfactory. In recent years, three kinds of novel hydrogels with unique structures and high mechanical strength have been developed. [2] Topological (TP) gels have figure-ofeight crosslinkers that can slide along polymer chains.[3] The gel swells to about 500 times its original weight and can be stretched to nearly 20 times its original length. The nanocomposite (NC) hydrogel is made from specific polymers with a water-swellable inorganic clay. [4] Most of the macromolecules are grafted onto nanoparticles, indicating that the nanoparticle clay acts as a highly multifunctional crosslinking agent. We believe that the high mechanical strength of this material has its origin in the very high functionality of the rigid crosslinked points and the lack of short chains between crosslinked components, as every active chain has to stretch between nanoparticles. The extension degree of a chain before breakage is controlled by the relationship between its relaxed end-to-end distance and its contour length, which is low for short chains. When a short chain in an NS hydrogel breaks, its load is thrown onto just one or two other adjacent chains, which dramatically increases their load. Hence, multiple chain fractures occur, causing voids and microcracks. However, in an NC hydrogel with large, rigid crosslinking points, the load from a single broken chain will be spread over many other chains, and the material is less likely to form the microcracks and voids responsible for initiating bulk failure. Gong et al. have reported a new method of obtaining strong and tough hydrogels by making double-network (DN) materials with a high molar ratio of the second network to the first network. In this case, the first network is highly crosslinked and the second network is loosely crosslinked.[5] These DN hydrogels demonstrate extremely high mechanical strength. By adding a third component to a DN gel, either a weakly crosslinked network or noncrosslinked linear chains, gels with high-strength and low-frictional coefficients were obtained. [6] Macromolecular microspheres (MMSs) have become an important structure in polymeric materials. The hydrogel microspheres on the micro-or nanoscale are known as microgels or nanogels, respectively. They are usually environmentally sensitive and are mainly used in drug delivery and other biomedical applications. [7] However, it is difficult to...

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“…However, PAA chains are known to form inter-and intra-molecular hydrogen bonds that act as sticking points and enhance the dissipation involved in pulling out the entanglements. 14 This assumption has been proven by the fact that the synthesized hydrogel is easily swollen in a basic solution to suppress hydrogen bonding and cannot be dissolved in a low pH solution. (See the supplement information.)…”

Section: Resultsmentioning

confidence: 99%

Formation and characterization of poly(acrylic acid) on silica particles irradiated by γ-ray radiation

et al. 2012

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Organic/inorganic hybrid gels were directly prepared by polymerization on the peroxide surface of silica particles where the particle surface was irradiated by a 60 Co γ-ray. These hydrogels have no residues of initiators or cross-linkers, so they can be used in biocompatible gel applications. Wide Raman spectroscopy was used to verify the interaction between the particles and poly(acrylic acid) (PAA). We observed that covalent bonds existing between the peroxide particles and acrylic acid, and the hydrogen bonds between the acrylic acids. For these studies, we prepared hydrogels by varying the particles' concentration and the size of the silica particles to classify the number of reaction sites, which are the dominant factor for the chemical reaction between the silica particles and PAA.

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Raman spectroscopic study of hydrogen bonding in aqueous carboxylic acid solutions. 3. Polyacrylic acid

Cited by 46 publications

References 9 publications

Polyacrylic acid (poly-A) as a chelant and dispersant

Polyacrylic acid (poly-A) as a chelant and dispersant

A Novel Hydrogel with High Mechanical Strength: A Macromolecular Microsphere Composite Hydrogel

Formation and characterization of poly(acrylic acid) on silica particles irradiated by γ-ray radiation

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