Browsing by Keyword "NMR"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Effect of addition of silica- and amine functionalized silica-nanoparticles on the microstructure of calcium silicate hydrate (C-S-H) gel(2015-07-05) Monasterio, Manuel; Gaitero, Juan J.; Erkizia, Edurne; Guerrero Bustos, Ana M.; Miccio, Luis A.; Dolado, Jorge S.; Cerveny, Silvina; Tecnalia Research & Innovation; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓNIn this work we study the influence of adding nano-silica (SiO2, Nyasil™) and aminopropyl (-(CH2)3-NH2,) functionalized silica nanoparticles (Stoga) during the synthesis of calcium-silicate-hydrate (C-S-H gel). Characterization by solid state 29Si NMR and ATR-FTIR spectroscopy showed that the addition of both particle types increases the average length of the silicate chains in C-S-H gel being this effect slightly more important in the case of Stoga particles. In addition, 13C NMR and XPS confirmed that the aminopropyl chain remains in the final product cleaved to silicon atoms at the end of the silicate chain of C-S-H gel whereas XRD measurements showed that this result in an increment in the basal distance compared with ordinary CSH. In addition, the dynamics of water within the pores of C-S-H gel was analyzed by broadband dielectric spectroscopy. We observed that water confined in C-S-H formed with the addition of nanoparticles is faster than that in plain C-S-H which can be related to a different porous structure in these materials.Item Effect of lanthanum 4-hydroxy cinnamate on the polymerisation, condensation and thermal stability of hybrid sol–gel formulations(2020-10-01) Suarez Vega, Ana; Agustín-Sáenz, Cecilia; Brusciotti, Fabiola; Somers, Anthony; Forsyth, Maria; INGENIERÍA DE SUPERFICIES; VALORIZACIÓN DE RESIDUOSHybrid organic–inorganic sol–gel based coatings are of increasing interest nowadays as conversion coating replacements due to their promising performance. They provide good barrier properties; however, they lack active corrosion protection. Lanthanum 4-hydroxy cinnamate [La(4-OHCin)3] was incorporated into a known sol–gel formulation with the aim of improving the overall corrosion resistance of the derived coating. Since the final properties of these sol–gel coatings are dependent on the hydrolysis and condensation reactions of the alkoxide precursors, as well as the polymerisation processes that occur in the organic component, the effect of adding an inhibiting agent, such as La(4-OHCin)3, on the sol–gel chemistry and the polymerisation process needs to be investigated. This study focuses on the role of La(4-OHCin)3 on the sol–gel formation when it is incorporated into two different sol–gel formulations (Si sol and Si–Ti sol). Its influence on hydrolysis and condensation reactions has been studied by 29Si NMR and the opening of the epoxide ring from one of the precursors has been monitored by 1H NMR and Fourier-transformed infrared. Differential scanning calorimetry and Thermogravimetric analysis have also been performed to investigate the effect of this compound on the thermal properties of the final materials synthesised. It has been observed that the addition of La(4-OHCin)3 plays an important catalytic role both in the organic and inorganic polymerisation of the different metal alkoxide precursors. Furthermore, this effect is enhanced when only silicon alkoxides are present in the formulation, as the titanium precursor also plays a role on this catalysis. [Figure not available: see fulltext.]Item Synthesis and characterisation of silica nanoparticles bearing different functional groups obtained via a two-stage method(2010-11) Berriozabal, Gemma; De Miguel, Yolanda R.; INGENIERÍA DE SUPERFICIES; MercadoSilica nanoparticles with different functionalities (amine, nitrile, phenyl and vinyl) have been synthesised via a two-stage method and characterised in depth. Analysis by TEM, DLS and AFM has shown that the sizes of these synthetic nanoparticles are mainly in the range of 60-100 nm. In addition, 13C and 29Si CP/MAS NMR spectroscopy has been used to provide evidence of the presence of the organic functional groups. Finally, zeta potential measurements have been used to determine the stability of the colloidal dispersions in each case.