Aluminum Polyphosphate Research Articles

Lanthanide Cryptates Entrapment in Aluminum Polyphosphate Gels

In this work, we report for the first time the preparation and spectroscopic investigation of [Tb⊂ Bipy.Bipy.Py(CO 2 Et 2 )] 3+ incorporated in aluminum polyphosphate gels. Gelation occurs under ambient atmosphere at room temperature, which is followed by syneresis, leading to transparent samples after 5-10 days. Transparent auto-standing films were also prepared. The gel samples were characterized by UV-visible absorption spectrophotometry, luminescence spectroscopy and lifetime measurements. The crypate absorption and emission spectra were not greatly affected by its incorporation within the gel matrix. The lifetime of the Tb 3+ 5 D 4 level increases from 0.7 ms to 1.0 ms after entrapment into the gel. The results imply that these systems are promising for application in fluoroimmunoassays, as well as for the design of new optical materials.

Lanthanide Cryptates Entrapment in Aluminum Polyphosphate Gels

In this work, we report for the first time the preparation and spectroscopic investigation of [Tb⊂ Bipy.Bipy.Py(CO 2 Et 2 )] 3+ incorporated in aluminum polyphosphate gels. Gelation occurs under ambient atmosphere at room temperature, which is followed by syneresis, leading to transparent samples after 5-10 days. Transparent auto-standing films were also prepared. The gel samples were characterized by UV-visible absorption spectrophotometry, luminescence spectroscopy and lifetime measurements. The crypate absorption and emission spectra were not greatly affected by its incorporation within the gel matrix. The lifetime of the Tb 3+ 5 D 4 level increases from 0.7 ms to 1.0 ms after entrapment into the gel. The results imply that these systems are promising for application in fluoroimmunoassays, as well as for the design of new optical materials.

Aluminium tripolyphosphate pigments for anticorrosive paints

The efficiency of two anticorrosive pigments containing aluminium polyphosphate was studied. Pigments were analysed by current analytical techniques and characterised by FT‐IR spectrometry. The anticorrosive properties of the selected pigments were evaluated following the electrochemical behaviour of a steel electrode in pigments suspensions. In a second stage, solvent‐borne paints with 30 and 10% v/v of the pigment and PVC/CPVC (pigment volume concentration/critical pigment volume concentration) ratio 0.8 were formulated. Three resins were chosen as film forming materials: an alkyd, an epoxy and a vinyl. The performance of the resulting anticorrosive paints was assessed by accelerated (salt spray cabinet and humidity chamber) and electrochemical tests (corrosion potential, ionic resistance and polarisation resistance). The anticorrosive performance of the tested paints was closely related with pigment composition. The nature of the resin was also of importance; in this sense, epoxy paints showed the best anticorrosive performance. Good correlation has been obtained between accelerated and electrochemical tests.

Aluminum Polyphosphate Nanoparticles: Preparation, Particle Size Determination, and Microchemistry

Admixture of aluminum nitrate, sodium polyphosphate, and ammonium hydroxide solutions yields stable dispersions of hydrated aluminum polyphosphate particles within a broad reagent concentration range. These particles are formed by liquid–liquid phase separation, for which a phase diagram was calculated using suitable models for concentrated electrolyte solutions. Particle effective diameters range from a few nanometers to many hundreds and are fractionated by centrifugation. Particle electrophoretic mobility is very low and the hydration degree is high (∼80% v/v). Dry nanoparticles (1- to 15-nm diameter as observed by TEM) as well as particle aggregates are obtained by lyophilization. Element (P, Al, and Na) mapping by ESI-TEM shows that particle aggregates have a core-and-shell morphology, with a higher content of P in the aggregate core and a higher Na content at the outer shell.

Improved latex film-glass adhesion under wet environments by using an aluminum polyphosphate filler

—Non-crystalline aluminum polyphosphate (A1PP) was added as a filler to poly(vinyl acetate) latex and the resulting dispersion was used both as a glass coating and as a glass-to-glass adhesive. Latex-coated glass samples were subjected to a grid adhesion test following the ASTM D 3359 standard, in which the samples are immersed in water. A1PP improves the latex polymer film adhesion to glass, as evidenced by coating film and adhesive joint stabilities. This is explained in terms of the formation of Al3+ ion bridges between the polymer-polyphosphate bicontinuous composite film and the glass surface.

Formation of opaque films by biomimetic process

The preparation of opaque white films with amorphous aluminium polyphosphate, crystalline calcium carbonate and poly(vinyl acetate) latex is described. Film optical properties were characterized by diffuse reflectance spectrophotometry; morphological film features were examined by SEM, TEM, STM and AFM. Domain organization and void formation were detected, with dimensions of the same order of magnitude as the wavelength of visible light and can thus account for the film optical properties. Calcium carbonate consumption was monitored by X-ray diffraction and is assigned to a chemical reaction with aluminium polyphosphate, in which a mixed Al-Ca carbonate-polyphosphate is formed. The process of film opacification is interpreted as a result of dispersion, chemical reaction and orientation of solid inorganic particles within the polymer network during the film drying process. A model is proposed for void formation, based on volume contraction of the swollen inorganic particles, at a stage when their rigid surfaces are bound to the polymeric matrix.

Nanosized Particles of Aluminum Polyphosphate

Precipitation of noncrystalline aluminum polyphosphate in aqueous medium yields different products, depending on the actual conditions used. Within the P:Al mol ratio = 0.4−0.6 in the reaction mixture, strongly hydrated nanosized particles are obtained. Under suitable drying and sampling procedures, these can be observed as individual entities in the transmission electron microscope. Evaporation of an aqueous dispersion yields large aggregates, probably formed by capillary adhesion and surface tension-driven coalescence. Room-temperature compression molding of the powders made from these particles yields translucent monoliths, as expected for superplastic nanosized particles.

Non-Crystalline Aluminum Polyphosphates: Preparation and Properties

Non-Crystalline Aluminum Polyphosphates: Preparation and Properties

Aluminum Polyphosphate Thermoreversible Gels: A Study by31P and27Al NMR Spectroscopy

The formation of thermoreversible gels from aqueous aluminum polyphosphate solutions was previously assigned to hydration-dependent interionic associations, but these were not elucidated. In the present work, aluminum-phosphate interactions were examined by31P- and27Al-NMR spectroscopy of aqueous aluminum polyphosphate solutions and gels, at various P/Al ratios and temperatures. The fraction of aluminum and phosphate groups actually involved in the sol–gel transition is small, as evidenced by the comparison of spectra of solutions at various P/Al ratios and temperatures, in which only minor spectral changes are actually associated with gel formation. Chemical groups responsible for network formation are mainly Al- (H2O)4(PO3)2groups, in which the phosphate ligands are polyphosphate chain-ends. Within the gels, a large fraction of total aluminum is found as hexaquoaluminum ions, as evidenced by27Al-NMR spectra; on the other hand,31P-NMR spectra show that most phosphate ions are associated. These data indicate that bonding and bridging involve both inner- and outer-coordination sphere interactions. The former depend on ligand exchange reactions with half-life on the order of magnitude of a few seconds, which explains the time dependence of thermoreversible sol–gel transformations, in this system.

Aluminium polyphosphate in the ectomycorrhizal fungus Suillus variegatus (Fr.) O. Kunze as revealed by energy dispersive spectrometry

SUMMARYThe aluminium detoxification mechanism of an ectomycorrhizal fungus, Suillus variegatus (Fr.) O. Kunze, grown on Petri dishes was studied using an atomic absorption spectrometer (AAS) and scanning transmission electronmicroscope with an electron dispersion photometer (STEM‐EDS). Higher concentrations of soluble Al in the growth medium resulted in abundant formation of aluminium polyphosphate granules in the hyphae, which have not been noted earlier in ectomycorrhizal fungi or in their mycorrhizas. EDTA washing and STEM‐EDS demonstrated that the granules were mainly located in the cell walls. The results suggest that growth of the fungal mycelium decreased as a result of higher Al and lower P concentrations inside the cells, as measured by AAS. The aluminium polyphosphate granules also contained varying amounts of other elements such as Ca, Cl, K, S, and Si.