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Mejía Hugo Fernando Giraldo Jiménez-Piqué Emilio Valdés Matías Procaccini Raúl Pellice Sergio 《Journal of Solid State Electrochemistry》2020,24(10):2451-2460
Journal of Solid State Electrochemistry - A novel material was developed using sol-gel chemistry and an environmental-friendly grafting process of clay nanoparticles. In a previous work of our... 相似文献
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N. C. Rosero-Navarro S. A. Pellice A. Durán S. Ceré M. Aparicio 《Journal of Sol-Gel Science and Technology》2009,52(1):31-40
The aim of this work is the synthesis and characterization of hybrid coatings doped with cerium salts for corrosion protection
of AA2024. The control of the inorganic and organic polymerization process allows the preparation of coatings with an open
structure and a hydrophilic character. These facts facilitate the incorporation and mobility of cerium ions through the structure,
enhancing its ability to promote a self-healing mechanism. The thermal treatment of the coatings has been limited to 120 °C
to preserve the mechanical properties of the alloy. The electrochemical behaviour of the coatings has been evaluated in 0.3
wt% NaCl solution by means of EIS technique. Electrochemical measurements evidence good barrier properties at initial immersion
time, and signals of corrosion inhibition from cerium ions at long immersion times could be assigned to the increasing of
the impedance modulus at low frequencies and the presence of cerium oxide/hydroxide precipitates. 相似文献
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M.A. Fanovich S.A. Pellice P.G. Galliano R.J.J. Williams 《Journal of Sol-Gel Science and Technology》2002,23(1):45-52
The crosslinking of blends of a silsesquioxane (SSO) derived from (3-methacryloxypropyl) trimethoxysilane, variable amounts of a vinylester resin (VE, dimethacrylate of bisphenol A), and benzoyl peroxide (BPO) or dicumyl peroxide (DCP) as initiators, was followed by differential scanning calorimetry (DSC). For the neat SSO a thermally-initiated polymerization was observed in the 150–250°C range, leading to a conversion close to 22% of the initial C=C groups. The final conversion could be increased to a maximum value close to 83%, by adding an initiator and using a thermal cycle attaining temperatures in the range of 200°C. The use of variable amounts of VE as a co-monomer produced a slight increase of the final conversion in SSO/VE/BPO blends. Neither the conversion of double-bonds nor the addition of the VE had any effect on the onset temperature of thermal degradation, which was associated to the presence of the methacryloxypropyl groups supplied by the SSO and the VE resin. However, a distinct two-step degradation process was observed in the presence of VE. Coatings based on SSO/VE/BPO blends exhibited more uniform thicknesses and lower values of the microhardness than those devoid of VE. However, the conversion of C=C groups did not show any significant effect on the values of microhardness. 相似文献
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S. A. Pellice D. P. Fasce R. J. J. Williams 《Journal of Polymer Science.Polymer Physics》2003,41(13):1451-1461
A polyhedral oligomeric silsesquioxane (POSS), consisting mainly of a mixture of octahedra, nonahedra, and decahedra with bulky and flexible organic substituents, with three secondary hydroxyls per organic group, was used to modify epoxy networks produced by the homopolymerization of diglycidyl ether of bisphenol A in the presence of benzyldimethylamine. Several physical, thermal, and mechanical properties of the cured materials containing 0, 10, 30, and 50 wt % POSS were determined. The addition of POSS increased the elastic modulus and the yield stress measured in uniaxial compression tests, mainly because of the increase in the cohesive energy density produced by hydrogen bonding through the hydroxyl groups. A constant yield stress/elastic modulus ratio equal to 0.03 was observed for different POSS concentrations and test temperatures. The glass‐transition temperature decreased with POSS addition because of the flexibility of organic branches present in the POSS structure and the decrease in the crosslink density (determined from the rubbery modulus). Although a combination of a reduction in the glass‐transition temperature (plasticization) with an increase in the glassy modulus (antiplasticization) is a well‐known phenomenon, what is original is that in this case it was not the result of the suppression (or reduction in intensity) of subglass relaxations but was produced by an increase in the cohesive energy density. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1451–1461, 2003 相似文献
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S. Pellice Pablo Galliano Y. Castro A. Durán 《Journal of Sol-Gel Science and Technology》2003,28(1):81-86
Hybrids sols from tetraetoxysilane (TEOS) and 3-(methacryloxypropyl) trimethoxysilane (-MPS) were prepared in acid medium for different TEOS/-MPS ratios and were modified by the addition of a colloidal silica suspension. The stability of the different sols was evaluated by viscosity measurements; the sols showed a Newtonian behaviour and the ageing effect was negligible even after two months from their preparation. Coatings were obtained by dipping at different withdrawal rates and heat-treated between 150 and 250°C. Transparent coatings with thickness higher than 4 m were reached for most of the studied compositions. The surface microhardness of coatings for each composition and thermal treatment was evaluated by the pencil hardness test. The thermal stability was followed by simultaneous thermogravimetric and differential thermal analysis (TGA-DTA) determining the limit temperatures at which the coatings can be treated without losingits hybrid character. A structural analysis was made by deconvolution of Fourier transformed infrared spectra (FTIR) of self-supported films observing the influence of the organic groups on the silica network. 相似文献
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Nataly Carolina Rosero-Navarro Pawel Figiel Roman Jedrzejewski Anna Biedunkiewicz Yolanda Castro Mario Aparicio Sergio Antonio Pellice Alicia Durán 《Journal of Sol-Gel Science and Technology》2010,54(3):301-311
The aim of this work was to study the effect of the incorporation of cerium nitrate in a silica-methacrylate sol–gel hybrid
matrix reinforced with silica nanoparticles. Sols, coatings and powders have been studied, focusing specially in the determination
of the redox ratio Ce3+/Ce4+ and films structure. Sols have been characterised using viscosity measurements and FT-IR spectroscopy, and powders and coatings
obtained with different Ce contents through UV–Vis and FT-IR spectroscopy, TGA, TEM, AFM and FE-SEM. The goal was to reach
the best compromise between maximum cerium concentration and coating stability to better understand the mechanisms acting
in active anti-corrosive processes. 相似文献
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