High Degree Of Neutralization Research Articles

Laponite-Doped Poly(acrylic acid-co-acrylamide) Hydrogels

Electroacoustic characterization of soft nanocomposites has provided unique insights into the microstructure of soft nanocomposites, including nanoparticle (NP)-doped hydrogels and polyelectrolyte hydrogels without NPs. An outstanding problem is how to interpret the electrokinetic sonic amplitude (ESA) of charged hydrogels bearing charged NPs because both components generate an acoustic response to the electrical forcing. To this end, we study a series of Laponite XLG-doped, neutralized poly(acrylic acid-co-acrylamide) hydrogels, drawing principally on the ESA, electrical conductivity, and linear viscoelastic rheology. The hydrogel charge density was varied by the fraction of acrylic acid monomer fAAc = 0–1 while maintaining the total monomer concentration ≈8 wt % with Laponite concentration ≈0.85 wt %. Upon comparison of data from this study to those in a recent benchmark study of charged hydrogels without NPs, Laponite doping increased the electroacoustic signal and ionic conductivity but decreased the hydrogel storage modulus. Mechanistic theoretical models predicting how the real part of the ESA (at low frequency) and ionic conductivity of polyelectrolyte hydrogels depend on fAAc were extended to Laponite-doped hydrogels, together furnishing an estimate of the partial molar volume of acrylamide (in polymer form) that is close to the value for pure acrylamide (based on its density and molecular weight). The generally lower storage modulus with Laponite doping contrasts with previous studies of Laponite-doped polyacrylamide and poly(acrylic acid) hydrogels and solutions. This seems to reflect the high degree of neutralization, which transforms an attraction between protonated carboxyl moieties and Laponite to an electrostatic repulsion. The hindering effects of polymerization and cross-linking on acrylic acid-co-acrylamide networks were also investigated by comparing the ESA and conductivity of hydrogels with their monomer solution counterparts. Systematically varying the ratio of charged to uncharged monomers, with and without chemical cross-linking, provides insights to benefit a broad range of technological applications for hydrogel nanocomposites.

Development status, key technologies, and prospects of neutralizer-free ion thrusters

<p indent="0mm">The ion thruster is one of the most widely used electric thrusters and is famous for its high specific impulse and efficiency, but there are some shortcomings of the conventional ion thruster, such as the complex structure and the difficulty of miniaturization. One of the most attractive solutions to make up for these shortcomings is the neutralizer-free ion thruster which can reduce the volume and mass of the ion propulsion system and improve the system reliability by canceling the neutralizer system. In this review, the principles, strengths, and weaknesses of the conventional ion thruster are summarized, which leads to the concept of the neutralizer-free ion thruster. Combined with the operations of ion thrusters in real space missions, the advantages of removing neutralizer systems are analyzed. According to the neutralization methods, the neutralizer-free ion thruster can be divided into two types which are the electronegative ion thruster and RF (radio-frequency) ion thruster based on the self-bias effect. At present, the neutralizer-free ion thruster is mainly developed in Europe, Japan, and the United States of America. Researchers in China also perform some numerical and experimental studies on the neutralizer-free ion thruster, but there is still no report on the relatively mature prototype model. Lastly, based on the application requirements of the space propulsion and characteristics of the neutralizer-free ion thruster, the key technologies of the neutralizer-free ion thruster are discussed: (1) For the sake of prolonging the service life and improving the beam performance, the choice of propellant in neutralizer-free ion thrusters, especially the electronegative ion thruster where the propellant should be electronegative, needs more consideration than conventional ion thrusters. (2) The voltages applied on the grid system are generally AC voltages. Thus, to extract the collimated ion beams with high neutralization degree, the determination of the frequency and amplitude of grid voltages should consider many factors, such as the propellant type, insulation design, and plasma properties. (3) The adjustment of the working mode becomes more complex in the neutralizer-free ion thruster, since it is more difficult to adjust the AC grid voltage than conventional DC grid voltages and the relationship between the AC grid voltage and thruster performance also needs further investigations. (4) The magnetic filter plays an important role in the electronegative ion thruster, but it should be optimized because it increases the volume and weight of the thruster and weakens the advantages of the neutralizer-free ion thruster. (5) The ion-ion plasma in the electronegative ion thruster and the sheath near the grid with AC voltages make the plasma characteristics in the neutralizer-free ion thruster quite different from the conventional ion thruster. It is critical to perform more studies on the plasma physics of the neutralizer-free ion thruster to better design the thruster and adjust its performance. Accordingly, it’s concluded that the investigations of the choice of the propellant, design of the magnetic filter and grid system, plasma physics, and flexible regulation method of the grid voltage should be focused on. Moreover, to further understand the performance of the neutralizer-free ion thruster, new methods for diagnosing this new type of thruster need to be developed.

Oil‐in‐water Pickering emulsion stabilization with oppositely charged polysaccharide particles: chitin nanocrystals/fucoidan complexes

Chitin nanocrystals (ChN) are insoluble particles that can be used as stabilizers for Pickering emulsions. Their unique cationic properties and antibacterial activity have generated considerable interest among researchers. However, ChN have remained largely underexplored. Furthermore, the droplets of the emulsions stabilized by ChN are as large as 10-100 μm, and their physical stability requires further improvement. Some studies have shown that the spontaneous reaction of oppositely charged particles can effectively stabilize the emulsions. Positively charged ChN and negatively charged fucoidan (F) were therefore compounded to stabilize Pickering emulsions, and the stability of these emulsions was analyzed qualitatively. The results showed that the composite particles comprising two polysaccharides in a mass ratio of 1:1 and at a pH of 2 (ChN1 -F1 -pH 2) possessed the lowest sulfate content (20.1%) and almost zero potential (-3 mV), indicating a high degree of neutralization of the positively charged amino group in ChN and the negatively charged sulfate group in F. Meanwhile, ChN1 -F1 -pH 2 displayed a dense network structure that improved the dispersibility and wettability (contact angle = 9.3°). Fourier transform infrared spectroscopy results confirmed that ChN and F were effectively combined through electrostatic interaction or neutralization to produce a polyelectrolyte complex. Furthermore, the particle size of the Pickering emulsion stabilized by ChN-F was significantly reduced, and the maximum size did not exceed 10 μm; the physical and storage stability also improved. The ChN1 -F1 -pH 2 emulsion presented excellent storage stability; in particular, the emulsions stabilized by ChN1 -F1 -pH 5 and ChN1 -F1 -pH 6 exhibited excellent flocculation stabilities. The size of the emulsion droplets stabilized by the oppositely charged polysaccharide particles (ChN-F complexes) reduced significantly. Furthermore, by changing the mass ratio and pH, the microstructure and binding degree of the complexes can be adjusted, thereby promoting their adsorption on the oil-water interface and improving the stability of the Pickering emulsion. © 2020 Society of Chemical Industry.

Development of a Carrier-Free Dry Powder Ofloxacin Formulation With Enhanced Aerosolization Properties

Tuberculosis (TB) is a serious infectious disease that affects more than new 10 million patients each year. Many of these cases are resistant to first-line drugs so second-line ones, like fluoroquinolones, need to be incorporated into the therapeutic. Ofloxacin (OF) is a fluoroquinolone which demonstrates high antibiotic activity against the bacteria that causes TB (M. tuberculosis). In this work, ionic complexes, composed by hyaluronic acid (HA) and OF, with different neutralization degrees, were prepared and processed by spray drying (SD) to obtain powders for inhalatory administration. Combining a formulation with high neutralization degree, high SD atomization air flowrate and the use of a high-performance collection cyclone, very good process yields were obtained. Carrier-free formulations with a loading of 0.39–0.46 gOF/gpowder showed excellent emitted, fine particle, and respirable fractions for capsule loadings of 25 and 100 mg. The ionic complexes demonstrated higher mucoadhesion than pure OF and HA. The best formulation did not affect CALU-3 cell viability up to a dose 6.5 times higher than the MIC90 reported to treat multi-drug resistant TB.

Effect of Multivalent Cations on Intermolecular Association of Isotactic and Atactic Poly(Methacrylic Acid) Chains in Aqueous Solutions.

The formation of nanoparticles of two poly(methacrylic acid) (PMA) isomers, atactic (aPMA) and isotactic (iPMA), was investigated in aqueous solutions in the presence of mono- (Na+) and multivalent cations (Mg2+ and La3+). Using dynamic (DLS) and static light scattering (SLS), we show that PMA nanoparticles have characteristics of microgel-like particles with a denser core and a swollen corona. iPMA aggregates are stable at a much higher degree of neutralization (αN) than the aPMA ones, indicating a much stronger association between iPMA chains. This is explained by proposing segregation of ionized and unionized carboxyl groups within the iPMA aggregates and subsequent cooperative hydrogen-bonding between COOH groups. The calculated shape parameter (ρ) suggests different behavior of both isomers in the presence of Mg2+ ions on one hand and Na+ and La3+ on the other. The microgel-like particles formed in the presence of Mg2+ ions have a more even mass distribution (possibly a no core-shell structure) in comparison with those in the presence of Na+ and La3+ ions. Differences between the aggregate structures in the presence of different ions are reflected also in calorimetric experiments and supported by pH and fluorimetric measurements. Reasons for different behavior in the presence of Mg2+ ions lie in specific properties of this cation, in particular in its strong hydration and preference towards monodentate binding to carboxylate groups.

Ресурсосберегающая технология обезвреживания фенолсодержащих промышленных сточных вод

We have developed a resource-saving, low-waste technology for the disposal of highly toxic phenol-containing wastewater that enables to utilize phenol and formaldehyde as an organic binder. The technology involves the use of technogenic raw materials («overresin» water from the production of phenol-formaldehyde resins, soft wood waste, waste from the production and processing of laminated plastics) and processes of regeneration, recovery and conversion of phenol. The optimal technological parameters of phenol sorption on wood sorbent and secondary poly/condensation were experimentally established. This in turn provides a high degree of neutralization and extraction of resin-forming components from wastewater and subsequent production wood-polymer thermoplastic structural composite and sodium phenolate on their basis.

Discussion about the Influence of Ionomers Neutralization Degree for Hot Tack Property Using New Evaluation Method

Ionomers are polymer materials with a small amount of ionic functional group, e.g. carboxylic acid, sulfuric acid, or their metal salts. Above all, poly(ethylene-co-methacrylic acid)(EMAA) neutralized with metal cations is the most widely used ionomers for industrial applications. When neutralization degree by metal ions increases, metal ions aggregate to form ion aggregations. In ionomers containing ion aggregations, ion hopping phenomena occurs in which metal ions repeat bonding and dissociating with unneutralized carboxylic acid. As a result, ionomer forms a pseudo-crosslinked structure. With this structure, ionomer realizes excellent mechanical properties for elasticity, processability, toughness, hot tackiness, and so on. These properties extend application of ionomers to sports goods, food packaging materials, and adhesive materials. In the high-speed automatic filling process, packaging films are heat-sealed almost simultaneously after feeding contents.Hot tack property is important for the high-speed filling process. By hot tack property we mean that adhesive force is stabilized when films in semi-molten state are put together. Development of hot tack property contributes to saving of process time, and simplification of sealing process improving productivity in food packaging. At present, ionomer is generally recognized to be superior material for hot tack property. The mechanism of the excellence of ionomer for the hot tack property has not been elucidated, yet. It is considered that systematic research of hot tack properties for ionomers should be conducted. In this research, at the beginning, we proposed a new evaluation method of the hot tack property. More reliable evaluation method than conventional one was proposed. Furthermore, by using the new evaluation method, the influence of the neutralization degree of the ionomer on hot tack property was examined. We examined new evaluation method for hot tack test data. Evaluation of hot tackiness is considered to be essential for the initial stage of peeling. In the conventional evaluation method, force at a specific time, i.e. delay time, is adopted for evaluation. The hot tack strength at the delay time is evaluated. For a new evaluation method, the average of hot tack strength in an appropriate peeling time range was determined. The new evaluation method using average hot tack strength leads to understand peeling behavior precisely in wider time range than conventional method. In this study, the average of hot tack strength in the time range from 0.2 to 0.5 s was employed. Unneutralized EMAA showed the highest hot tack strength at seal temperature 80℃. However, the hot tack strength drastically decreased at seal temperature higher than 80℃. Though hot tack strength of ionomer was lower than unneutralized EMAA, it decreased slowly with temperature increase in comparison with unneutralized EMAA samples. Ionomer samples showed higher hot tack strength than unneutralized EMAA finally in the high temperature range (80-120℃). From these results, it was found that the ionomer samples keep hot tackiness in wider temperature range than unneutralized EMAA samples. The neutralization degree of 20% showed the highest hot tack strength. It was found that the ionomer consisting of a neutralization degree of 20% showed the highest hot tack property in the peel time range of 0.2 to 0.5 s in this study From these results, it was indicated that the presence of sodium ion improves the hot tack property. Neutralization degree of 20% improved the hot tack property remarkably. We expect ion hopping is related for this hot tack mechanism. For the ionomer of low neutralization degree, a large number of unneutralized carboxyl acid groups exit. Ion hopping due to acid cation exchange frequently occur because of existence of unneutralized carboxyl acid groups causing reconstruction to steady structure. In the case of high degree of neutralization, unneutralized carboxyl acid groups hardly exist. Ion hopping is not easy to occur because of lack of unneutralized carboxyl acid groups. Molecular chain diffusion is caused by ion hopping affecting structure of ion bondings. It is considered that lack of molecular chain diffusion caused decrease of hot tack property for ionomer samples of high degree of neutralization. Therefore, the hot tack strength of the ionomer is decreased at high degree of neutralization.

Aerogels made of chitosan and chondroitin sulfate at high degree of neutralization: Biological properties toward wound healing.

In this study, highly neutralized, highly porous, and ultralight polymeric aerogels prepared from aqueous colloidal suspensions of chitosan (CS) and chondroitin sulfate (ChS) nanocomplexes, formulated as quasi-equimolar amounts of both, are described. These aerogels were designed as healing agents under the inspiration of minimizing the amount of matter applied to wounds, reducing the electrostatic potential of the material and avoiding covalent cross-linkers in order to decrease metabolic stress over wounds. Aerogels synthesized under these criteria are biocompatible and provide specific properties for the induction of wound healing. They do not affect neither the metabolic activity of cultured 3T3 fibroblasts nor the biochemical parameters of experimental animals, open wounds close significantly faster and, unlike control wounds, complete reepithelialization and scarring can be attained 14 days after surgery. Because of its hydration abilities, rapid adaptation to the wound bed and the early accelerator effect of wound closure, the CS/ChS aerogels appear to be functional inducers of the healing. Previous information show that CS/ChS aerogels improve wound bed quality, increase granulation tissue and have pain suppressive effect. CS/ChS aerogels are useful as safe, inexpensive and easy to handle materials for topical applications, such as skin chronic wounds. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2464-2471, 2018.

Formation of W/O Microemulsions in the Extraction of the Lanthanide Series by Purified Cyanex 301

ABSTRACTThe formation of water-in-oil (W/O) microemulsions during the extraction of the series of trivalent lanthanides Ln(III) by bis(2,4,4-trimethylpentyl)dithiophosphinic acid (HC301, also known as purified Cyanex 301) was studied. The phenomena in the formation of W/O microemulsions were similar in the extraction of all Ln(III) by HC301 at a high neutralization degree (50%), according to the measurement of the distribution ratios of Ln(III) and the concentrations of Na+ and NO3- in the organic phase, IR spectroscopy, and dynamic light scattering (DLS). W/O microemulsions also formed at a low neutralization degree (15%) for the extraction of heavy Ln(III). The coordination environment of the representative heavy lanthanide Ho(III) in the extracted complexes was monitored by absorption spectroscopy and extended X-ray absorption fine structure (EXAFS). Unlike the light lanthanide, Nd(III) and Ho(III) in the organic phase did not directly coordinate with the HC301 anions regardless of whether W/O microemulsions formed, which further demonstrated the different extraction behavior of HC301 toward the light lanthanides and the heavy lanthanides.

The Politics of Security Deployment of Security Operatives to Jos Metropolis, Plateau State, Nigeria 2001-2014

Abstract The paper examines the politics of security deployment by the Federal Government of Nigeria to Jos, metropolis. A cross-sectional study was conducted and Public Opinion Theory adopted. Methodologically, mixed methods of data collection were conducted that involved the administration of 377 questionnaires to adult respondents, six In-Depth Interviews with religious and community leaders while three Key Informant Interviews with security personnel working with Special Task Force. The survey reveals that, the deployment of Mobile Police from 2001-2010 and the formation of Special Task Force in 2010 has generated mixed reactions and divergent perceptions among the residents of Jos metropolis. Majority of the ethnic groups that are predominantly Christians were more contented with the deployment of the Mobile Police whereas ethnic groups that are dominantly Muslims questioned the neutrality, capability, performance and strength of the Nigerian Police Force in managing the crises. The study recommends that, security personnel should display high degree of neutrality in order to earn the confidence of the residents and change their perceptions.

Dynamic selection of evolutionary operators based on online learning and fitness landscape analysis

Self-adaptive mechanisms for the identification of the most suitable variation operator in evolutionary algorithms rely almost exclusively on the measurement of the fitness of the offspring, which may not be sufficient to assess the optimality of an operator (e.g., in a landscape with an high degree of neutrality). This paper proposes a novel adaptive operator selection mechanism which uses a set of four fitness landscape analysis techniques and an online learning algorithm, dynamic weighted majority, to provide more detailed information about the search space to better determine the most suitable crossover operator. Experimental analysis on the capacitated arc routing problem has demonstrated that different crossover operators behave differently during the search process, and selecting the proper one adaptively can lead to more promising results.

Evolution of functional diversification within quasispecies.

According to quasispecies theory, high mutation rates limit the amount of information genomes can store (Eigen’s Paradox), whereas genomes with higher degrees of neutrality may be selected even at the expenses of higher replication rates (the “survival of the flattest” effect). Introducing a complex genotype to phenotype map, such as RNA folding, epitomizes such effect because of the existence of neutral networks and their exploitation by evolution, affecting both population structure and genome composition. We reexamine these classical results in the light of an RNA-based system that can evolve its own ecology. Contrary to expectations, we find that quasispecies evolving at high mutation rates are steep and characterized by one master sequence. Importantly, the analysis of the system and the characterization of the evolved quasispecies reveal the emergence of functionalities as phenotypes of nonreplicating genotypes, whose presence is crucial for the overall viability and stability of the system. In other words, the master sequence codes for the information of the entire ecosystem, whereas the decoding happens, stochastically, through mutations. We show that this solution quickly outcompetes strategies based on genomes with a high degree of neutrality. In conclusion, individually coded but ecosystem-based diversity evolves and persists indefinitely close to the Information Threshold.

Study on the Storage Stability of High Neutralization Degree Phosphate-Bonded No-Bake Sand

Effect of particle size of Al (OH)3 and Mg-containing modifier of binder and hardener on the dry strength and storage stability of high neutralization degree phosphate-bonded no-bake sand were studied. Results show that particle size of Al (OH)3 has little effect on the dry strength and storage stability when its varieties are 4.552 μ m toothpaste-grade Al (OH)3 and 6.136μm industrial special Al (OH)3, 6.136μm industrial special Al (OH)3 is more appropriate in consideration of cost and source. Adding Mg-containing modifier to binder code 32B8M15B cannot improve the dry strength and storage stability, but adopting compound modifier, 2% fused magnesia powder+2% iron powder+4% copper powder ,can obtain better properties , dry strength can reach 3.022MPa, and the minimum strength is above 1MPa with humidity fluctuation from 21%RH to 60%RH in 18 days.

Differences in association behavior of isotactic and atactic poly(methacrylic acid)

In this paper we show by light scattering techniques that polymer tacticity introduces an opposite association behavior in the case of aqueous solution of poly(methacrylic acid) in the presence of 0.1 M NaCl. Aggregates of highly stereoregular isotactic poly(methacrylic acid), iPMA, are disrupted by shear and gradually reform in solution at rest, whereas those of the usual atactic form, aPMA, multiply as a result of mechanical stress (phenomenon of negative thixotropy) and gradually decrease in number after its cessation. The aggregates have characteristics of microgel particles and may act as precursors for temperature induced gelation at higher concentrations. According to the shape parameter ρ (∼0.6 and ∼0.70 for iPMA and aPMA, respectively) iPMA aggregates have a denser core than aPMA ones. Additional differences between both isomers are demonstrated at higher degrees of neutralization, αN, through the analysis of the polyelectrolyte slow mode, which was identified for all αN > 0.25 with iPMA but only for αN = 1 with aPMA.

Optimizing Study of Solidification Agent with High Neutralization Degree Compound Phosphate-Bonded No-Bake Sand by Orthogonal Test

Regarding dry strength and storage strength of high neutralization degree compound phosphate no-bake sand as index, optimization was analyzed on the ratios of solidification agent to obtain the appropriate adding amount in different environment by orthogonal test, and influence of optimum formula on the storage stability of the no-bake sand was studied. The results show that, in condition of up 25°C, when humidity is more than 60% RH, the formula of solidification agent is 5% Mg-contained powder + 2% Al-contained powder + 4% Zn-contained powder, its no-bake sand sample has high dry strength and good storage stability. When humidity is less than 60% RH, the formula of solidification agent is 2% Mg-contained powder + 2% Al-contained powder + 4% Zn-contained powder, its no-bake sand sample has high dry strength and good storage stability.

Invited Review Article: The electrostatic plasma lens

The fundamental principles, experimental results, and potential applications of the electrostatic plasma lens for focusing and manipulating high-current, energetic, heavy ion beams are reviewed. First described almost 50 years ago, this optical beam device provides space charge neutralization of the ion beam within the lens volume, and thus provides an effective and unique tool for focusing high current beams where a high degree of neutralization is essential to prevent beam blow-up. Short and long lenses have been explored, and a lens in which the magnetic field is provided by rare-earth permanent magnets has been demonstrated. Applications include the use of this kind of optical tool for laboratory ion beam manipulation, high dose ion implantation, heavy ion accelerator injection, in heavy ion fusion, and other high technology.

Study of Environmentally Friendly Phosphate-Bonded No-Bake Sand

Regarding dry strength as the index, and considering liftability and storage stability, effects of solidification agent amount and organics N on the property of high neutralization degree phosphate no-bake sand mold/core were studied by modifying the binder coded 32B8M15 and adding solidification agent fused MgO in sand mixing. A new type of compound phosphate binder coded 32B8M15N4 is developed, and results indicate that, at environment condition of below 15°C and 50% RH, the proper solidification agent amount is 5% when using high neutralization degree binder coded 32B8M15N4 (its addition amount is 3%) to make no-bake sand, its molding sand sample has high dry strength and good storage stability, its compressive strength, σ0, σ1, σ2, σ3, σ4 is 2.33 MPa, 2.27 MPa, 2.01 MPa, 2.03 MPa, 2 MPa separately.

Synthesis and pH/Temperature‐Responsive Behavior of PLLA‐b‐PDMAEMA Block Polyelectrolytes Prepared via ROP and ATRP

AbstractWell‐defined diblock poly(L‐lactide)‐block‐poly(dimethylamino‐2‐ethyl methacrylate) (PLLA‐b‐PDMAEMA) copolymers were synthesized by combining ROP of LLA and ATRP of DMAEMA, from a dual‐initiator 2‐hydroxylethyl 2‐bromoisobutyrate. The molecular characterization of these diblock copolymers was performed using 1H NMR, FT‐IR, and GPC‐MALLS analysis. The responsive behavior of these diblock copolymers in aqueous solutions at different pH and temperatures were investigated using DLS. Results show that both higher pH and temperature result in a higher degree of neutralization, weaker hydrogen bonding, and micellar aggregation. As observed by TEM, changes in micellar morphology are in accordance with DLS results. magnified image

Effect of Type and Concentration of Ionomer Compatibilizer on the Hdpe/ Ionomer/ Clay Nanocomposites Morphology

A study of the effect of an ionomer compatibilizer (surlyn® 9520 and 9721, both with zinc as the neutralizing cation) on the morphology and properties of a high density polyethylene (HDPE) - montmorillonite clay nanocomposite was carried out. The nanoclay used was cloisite 20A®. Polyethylene /Ionomer /Clay nanocomposites were prepared via melt mixing in a twin screw extruder. The nanoclay dispersion and exfoliation were examined through X-Ray Difraction (XRD) and Scanning Electron Microscopy (SEM). TGA was carried out to determine the effect of nanoclay on the thermal stability of the HDPE nanocomposites. Results showed that both ionomers impart a marked compatibility between the polymer and the nanoclay, promoting the exfoliation of the nanoclay within the HDPE matrix. Nonetheless, ionomer 9520 (with the higher degree of neutralization) at 10 and 12 wt% content produced completely exfoliated morphologies, whereas, the ionomer 9721 produced a lesser degree of exfoliation with few tactoids.

The State of NaOH in NaOH/Poly(Sodium Acrylate) Composite

NaOH/poly(sodium acrylate) composites were prepared by in situ polymerization of acrylic acid with an overneutralization level by adding excess NaOH. The composites were studied by XRD, IR and 23Na MAS NMR spectroscopy. The results showed that the high neutralization degree (>100%) may lead to a complete polymerization. Both XRD and 23Na MAS NMR spectra did not show any peaks of phase-separated NaOH or Na2CO3 until the neutralization degree was up to 217.5%. It can be presumed that the aggregates of Na+ ions can contain approximately two Na+ units for every carboxyl group before the phase separation.