Manufacture and testing of water-borne paints by using vinyl latex containing VeoVa10® monomer

Two different water-borne dispersions (latex) containing different amounts of vinyl acetate and a commercial vinyl ester monomer (VeoVa10) were evaluated by incorporating them in paint formulations for wall protection. Three paint formulations were prepared with different PVC values. The main properties such as hiding power, washability, tension of adhesion and elasticity were assessed. Changes in color, gloss and adhesion and the extension of chalking, checking, cracking and blistering were also evaluated in normal and accelerated weathering tests. The results indicate that both dispersions are suitable for wall protection (interior or exterior, permanent or temporary protection) and  they are compatible with the most common additives used in the Argentinean and Mercosur markets. The presence of VeoVa10 in the binder composition improves the water and UV resistance of the paint. A styrenic-acrylic latex, commonly used in the local marked, was used as comparative product.Centro de Investigación y Desarrollo en Tecnología de PinturasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Dilute-solution viscosimetry and solution properties of colloidal polymers

The intrinsic viscosities of a terpolymer of methyl methacrylate, ethyl acrylate and methacrylic acid, prepared by semicontinuous emulsión polymerization (látex) were measured in acetone and THF at different temperatures. Data were analyzed with the aid of the equations of Huggins, Kraemer, Martín, Schulz-Blaschke and an equation recently suggested by Rao. Relationships between different parameters were also considered The effects of low-molecular weight and water-soluble compounds on the intrinsic viscosities were observed for uncleaned samples of látex as compared to samples purified, by single precipitation or by dissolution and precipitation from THF. Solvent powers and effects of degree of purification and temperature on viscosity are discussed. Polymer-solvents interactions are discussed in terms of the acceptor / donor properties of the solvents

Espectroscopia vibracional de sólidos inorgánicos

Este trabajo se llevó a cabo como parte de un programa de estudio de sales de pentaciano-L-metalatos, en el que interesa especialmente el comportamiento vibracional del agua de hidratación, como resultado de los enlaces de hidrógeno que puede formar el agua como donor y/o aceptor y de la coordinación a cationes. En este último aspecto, interesaba extender a los cationes K+ y Mg2+ , en forma de los correspondientes nitroprusiatos, la correlación propuesta hace mucho tiempo entre el número de ondas del estiramiento de los grupos OH (OD) de moléculas de agua no afectadas a puentes de hidrógeno y coordinadas a cationes y el poder polarizante de estos últimos (definido como el cociente entre la carga y el radio) que estudios previos en nitro prusiatos de metales alcalinos y alcalino-térreos daban como válida para algunos de esos cationes (100).Tesis digitalizada en SEDICI gracias a la Biblioteca Central de la Facultad de Ciencias Exactas (UNLP).Facultad de Ciencias Exacta

Etude visant à comparer les résultats de différents types de bandelettes urinaires en fonction de leur mode d’utilisation chez le chien

Trois marques de bandelettes urinaires à dix plages réactives, dont deux destinées à la médecine humaine et une à usage strictement vétérinaire sont prises en exemple dans cette l’étude. Une première partie bibliographique décrit d’abord la structure, les principes et les gammes analytiques de ces bandelettes qui montrent de grandes similitudes, puis s’intéresse aux performances des dix plages réactives mises en jeux pour l’espèce canine. La partie expérimentale, vise à comparer le mode d’utilisation par « immersion », lorsque la bandelette est plongée entièrement dans l’urine comme recommandé par toutes les notices d’utilisation et le mode d’utilisation par « imbibition », lorsqu’une goutte d’urine est déposée sur chaque plage test comme fréquemment réalisé en médecine vétérinaire. Il a également été comparé les trois marques de bandelettes entre elles, ainsi que la plage test densité à un réfractomètre portable et la plage test pH à un papier pH. L’analyse des résultats indique que les deux modes d’utilisation semblent pouvoir s’utiliser indifféremment. Le nombre relativement faible de spécimens inclus et la puissance statistique des tests incitent cependant à une interprétation prudente des résultats, notamment pour certaines plages réactives

Evaluation of pH-sensitive poly(2-hydroxyethyl methacrylate-co-2 (diisopropylamino)ethyl methacrylate) copolymers as drug delivery systems for potential applications in ophthalmic therapies/ocular delivery of drugs

Smart polymers like pH sensitive systems can improve different pharmacological treatment. In this work the behavior of copolymers containing 2-hydroxyethyl methacrylate (HEMA) with different proportions of 2-(diisopropylamino) ethyl methacrylate (DPA) and different amounts of cross-linker agent, ethylene glycol dimethacrylate (EGDMA) are evaluated as pH-sensitive drug delivery systems for potential application in ophthalmic therapies. A detailed characterization of the pH-responsive behavior was performed by swelling studies and scanning electron microscopy (SEM) analysis. Drug loading and release studies at different pH values were evaluated using Rhodamine 6G (Rh6G) as a model drug. The interaction between Rh6G and hydrogels was studied by Fourier Transform Infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The results show that the presence of DPA in the copolymers confers pH-responsive properties to the polymer, as noted in swelling and SEM studies, when the pH decreases below 7.40 the swelling degree increases and a porous morphology is observed. The apparent pKa of copolymers was estimated between 6.80 and 7.17 depending on the composition. The amount of Rh6G loaded depends mainly on the medium pH and the interaction between the drug and the copolymers, observed by SEM and FTIR spectrum. The release of Rh6G of copolymers p(HEMA/DPA) show a normal Fickian or anomalous diffusion behavior at different pH values, depending on the HEMA/DPA ratio.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasCentro de Investigación y Desarrollo en Tecnología de PinturasFacultad de Ingenierí

Evaluation of pH-sensitive poly(2-hydroxyethyl methacrylate-co-2 (diisopropylamino)ethyl methacrylate) copolymers as drug delivery systems for potential applications in ophthalmic therapies/ocular delivery of drugs

Smart polymers like pH sensitive systems can improve different pharmacological treatment. In this work the behavior of copolymers containing 2-hydroxyethyl methacrylate (HEMA) with different proportions of 2-(diisopropylamino) ethyl methacrylate (DPA) and different amounts of cross-linker agent, ethylene glycol dimethacrylate (EGDMA) are evaluated as pH-sensitive drug delivery systems for potential application in ophthalmic therapies. A detailed characterization of the pH-responsive behavior was performed by swelling studies and scanning electron microscopy (SEM) analysis. Drug loading and release studies at different pH values were evaluated using Rhodamine 6G (Rh6G) as a model drug. The interaction between Rh6G and hydrogels was studied by Fourier Transform Infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The results show that the presence of DPA in the copolymers confers pH-responsive properties to the polymer, as noted in swelling and SEM studies, when the pH decreases below 7.40 the swelling degree increases and a porous morphology is observed. The apparent pKa of copolymers was estimated between 6.80 and 7.17 depending on the composition. The amount of Rh6G loaded depends mainly on the medium pH and the interaction between the drug and the copolymers, observed by SEM and FTIR spectrum. The release of Rh6G of copolymers p(HEMA/DPA) show a normal Fickian or anomalous diffusion behavior at different pH values, depending on the HEMA/DPA ratio.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasCentro de Investigación y Desarrollo en Tecnología de PinturasFacultad de Ingenierí

Espectroscopia vibracional de sólidos inorgánicos

Este trabajo se llevó a cabo como parte de un programa de estudio de sales de pentaciano-L-metalatos, en el que interesa especialmente el comportamiento vibracional del agua de hidratación, como resultado de los enlaces de hidrógeno que puede formar el agua como donor y/o aceptor y de la coordinación a cationes. En este último aspecto, interesaba extender a los cationes K+ y Mg2+ , en forma de los correspondientes nitroprusiatos, la correlación propuesta hace mucho tiempo entre el número de ondas del estiramiento de los grupos OH (OD) de moléculas de agua no afectadas a puentes de hidrógeno y coordinadas a cationes y el poder polarizante de estos últimos (definido como el cociente entre la carga y el radio) que estudios previos en nitro prusiatos de metales alcalinos y alcalino-térreos daban como válida para algunos de esos cationes (100).Tesis digitalizada en SEDICI gracias a la Biblioteca Central de la Facultad de Ciencias Exactas (UNLP).Facultad de Ciencias Exacta

Corn starch-based coating enriched with natamycin as an active compound to control mold contamination on semi-hard cheese during ripening

The effectiveness of natamycin supported in corn starch-based films to control environmental molds (mainly Penicillium spp) activity that could colonize the surface of semi-hard cheese during ripening, was evaluated. The starch amount was maximized, and this was achieved by adding polyvinyl alcohol (PVA) and also polyurethane (PU) to the formulation. The PU acted as plasticizer and also provided functional groups that interacted with the natamycin and affected its diffusion. When 5 % PU was added, the natamycin migration of the coating doped with 1% natamycin was reduced by half. The natamycin distribution on both sides of the film was also evaluated, concluding that, in line with the reduced migration, when polyurethane is included, the formulation presents high hydrophobicity and natamycin is left with a preferential distribution towards the air face (exterior). For microbiological tests, microorganisms were isolated from cheese factories. Natamycin solutions showed inhibitory effect against environmental molds including Penicillium spp. Accordingly, films loaded with 0.1 % natamycin showed a significant inhibitory effect against Penicillium spp. The polymer combination in this work was optimized to obtain an active coating with good physicochemical properties and enriched with natamycin that has proven to be available for acting against molds and preferentially on the surface exposed to potential mold attack during ripening.Fil: González Forte, Lucía del Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Amalvy, Javier. Universidad Tecnológica Nacional. Facultad Regional La Plata. Centro de Investigación y Desarrollo en Ciencia y Tecnología de Materiales; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Bertola, Nora Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin

Desarrollo y evaluación de electrolitos poliméricos con aplicaciones en baterías de litio

Las baterías ion Li- polímero son una variación de las baterías de ion-Li y aunque sus características son muy similares, las primeras utilizan un polímero sólido como electrolito, permiten una mayor densidad de energía y tienen una velocidad de descarga bastante superior. A fin de contribuir con la búsqueda de alternativas viables, se prepararon películas de poliuretano (PU), poli(óxido de etileno) (PEO) y mezclas de PU y PEO. Posteriormente mediante diferentes estrategias se incorporó a las películas una sal de Li en varias concentraciones. Las películas puras de PU presentan una alta resistencia a la conducción, pero la combinación con PEO permite obtener sistemas con valores de conductividad adecuados para su empleo en baterías.Facultad de Ciencias Exacta

Starch/Polyvinyl Alcohol Blends Containing Polyurethane as Plasticizer

Starch-based films containing 70wt% of starch and a combination of poly(vinyl alcohol) and a low glass transition temperature polyurethane as plasticizer were prepared. The effect of PVA/PU ratio content on the morphology and physical properties was investigated by infrared spectroscopy (FTIR), X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy and measurements of mechanical properties and water vapor permeability. A relative small amount of PU (less than 15 wt%), significantly changes the properties of the blend due to intermolecular hydrogen bonding interactions between the three components. FTIR and XRD results indicate that blends containing PU are more amorphous than the pure starch/PVA blend and SEM images show a homogeneous matrix due to the good compatibility between starch and PU. Incorporation of PU to the starch/PVA blend shifts the glass transition temperature to lower values and reduce the elastic modulus, indicating a successful plasticization effect. The resulting blends produce films with improved physical properties.Facultad de Ciencias Exacta