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Perrin, F.X.; Nguyen, Van Nhan; Vernet, Jean

doi:10.1023/a:1026081100860

Cited by 78 publications

(59 citation statements)

References 12 publications

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“…To identify the effect of the ligands on the nature of the coordination with the zirconium atom, 5 complexes were synthesised and respective infrared spectra recorded in the 1300-1800 cm −1 spectral range, as represented in Table 2. This is well known to be the region where the carboxylic vibration bands are usually identified [32]. Within this spectral window TPOZ shows 6 absorption bands centred at 1350, 1360, 1380, 1440, 1460 and 1470 cm −1 ascribable to the stretching vibrations of the aliphatic CH groups contained in the propoxide group [33].…”

Section: Ftir Resultsmentioning

confidence: 85%

Effect of organic chelates on the performance of hybrid sol–gel coated AA 2024-T3 aluminium alloys

Varma

Colreavy

Cassidy³

et al. 2009

Progress in Organic Coatings

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a b s t r a c tSol-gels are organic-inorganic polymers formed by hydrolysis/condensation reactions of alkoxide precursors, primarily silanes, which have found applications as electronic, optical and protective coatings. These coatings possess important characteristics such as chemical stability, physical strength and scratch resistance. Further performance improvement is achieved through the incorporation of zirconium and titanium based nanoparticles, also formed through the sol-gel process. However due to the inherent difference in the reactivity of the precursors, the hydrolysis of each precursor must be carried out separately before being combined for final condensation. Zirconium precursors are commonly chelated using acetic acids, prior to hydrolysis, to lower the hydrolysis rate.In this body of work various ligands such as organic acids, acetyl acetone (AcAc) and 2,2 -bipyridine (Bipy) were used to control the zirconium hydrolysis reaction and form nanoparticles within the silane sol matrix.Nanoparticle modified coatings formed from the silane sol on AA 2024-T3 aluminium were characterised spectroscopically, electrochemically and calorimetrically to evaluate the potential effect of the different chelates on the final film properties while neutral salt spray tests were performed to study their anti-corrosion performance. Results indicate that the acid ligand modified coatings provided the best performance followed by AcAc, while Bipy was the poorest. In all cases the zirconium nanoparticle improved the protective properties of the sol-gel coating.

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Section: Ftir Resultsmentioning

confidence: 85%

Effect of organic chelates on the performance of hybrid sol–gel coated AA 2024-T3 aluminium alloys

Varma

Colreavy

Cassidy³

et al. 2009

Progress in Organic Coatings

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“…The above results show that only organic moieties are released into water. Because the weight loss increases with the titania content in the hybrids, we believe that a large part of the released organic compounds comes from the slow hydrolysis of the residual TiOBu groups (mostly bridging butoxy groups that are still present in the structure of the final hybrid 14 ) and/or TiOAc groups that are likely promoted by the plasticizing effect of the initially entering water molecules. It must be emphasized that the hydrolysis of COOTi and BuOTi bonds is a slow process: after 2 days of immersion, no leaching can be detected by elemental analysis for the AP-4 and AP-6 samples.…”

Section: Mass Change Measurementsmentioning

confidence: 99%

Water absorption characteristics of hybrid materials incorporating tetrabutyl titanate with acrylic polymer via sol–gel process

Perrin

Nguyen

Vernet

2005

J of Applied Polymer Sci

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ABSTRACT:The sol-gel process was used to prepare organic/inorganic hybrids utilizing a terpolymer of n-butyl methacrylate, methyl methacrylate, and methacrylic acid as an organic phase and titanium tetrabutoxide as a precursor of the inorganic phase. Such hybrid materials may be of interest as primers for corrosion protection of metal substrates. In the absence of electrochemical influence, which is usually provided by anticorrosive pigments in current protective coatings, the barrier mechanism becomes one of the basic elements for protecting metals against atmospheric corrosion. In that context, we report the water uptake characteristics of hybrid films with titania content up to 16.3 wt %. The slow hydrolysis of butoxy, acetate, and carboxylate ligands, which becomes more and more obvious with an increase in titanium oxide cluster content, is found to produce a chemically driven force for water uptake in hybrids. The 4.6 wt % TiO 2 hybrid results in the best balance of properties with a far lower diffusion coefficient and nearly the same amount of water absorbed at saturation compared to the polymer matrix.

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“…[12,13] In ref. [11,14] , it was shown that the formation of metal carboxylate bonds between the lateral acid groups of an acrylic polymer and titanium alkoxide was an effective way to compatibilize the organic component and the inorganic component. The aim of this work is to investigate how the polymer dynamics are affected by the titania sol-gel component by studying the change in the dynamics of the methacrylate terpolymer/titania hybrids with frequency and temperature.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Study of the Effect of a Sol‐Gel Inorganic Network on Polymeric Relaxation Dynamics in Acrylic/Titania Hybrids

Perrin

Nguyen

Vernet

2005

Macro Chemistry & Physics

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In this research, poly[(methyl methacrylate)-co-(butyl methacrylate)-co-(methacrylic acid)]/TiO 2 hybrids were prepared by the sol-gel process. The copolymer composition was 16 mol-% methyl methacrylate (MMA), 80 mol-% butyl methacrylate (BMA) and 4 mol-% methacrylic acid (MA). The dielectric properties of the hybrids with varying titania content were measured over the frequency range 0.1 Hz to 100 kHz and between 25 and 160 8C. In addition, the hybrids were investigated using differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). In the given frequency range, a single relaxation peak was observed both by dielectric relaxation spectroscopy (DRS) and DMTA. The single relaxation observed by DRS behaves in the manner of an a-relaxation, with the frequency-temperature locus showing non-Arrhenius behavior (curved downwards like a VTF law). The change in the DRS and DMTA characteristics in hybrids compared to the pure polymer reflect the presence of antagonistic mechanisms controlling the dynamics of the polymer chains: nanodomains with enhanced and restricted mobilities are suggested to be responsible for the broadening of the isochronal dielectric loss curve toward, respectively, the low and the high temperature sides. Combining the DSC and DRS results, it can be inferred that the domains with enhanced mobility result from internal and external plasticization effects that reduce the intermolecular hydrogen bonds between the polymer chains. Besides, the motion of polymer chains is found to be significantly hindered by the titania network, due to the presence of iono-covalent bonds between the polymer and titania and geometrical restrictions in high junction-point density and titania-rich microphases. From the Arrhenius plot, it is also shown that the addition of sol-gel titania more severely hinders the segmental motion of the macromolecular chains than the local motion of the lateral groups (b relaxation).Simplified schematic morphology for the poly(MMA-co-BMA-co-MA)/TiO 2 hybrids.

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Untitled

Cited by 78 publications

References 12 publications

Effect of organic chelates on the performance of hybrid sol–gel coated AA 2024-T3 aluminium alloys

Effect of organic chelates on the performance of hybrid sol–gel coated AA 2024-T3 aluminium alloys

Water absorption characteristics of hybrid materials incorporating tetrabutyl titanate with acrylic polymer via sol–gel process

Dielectric Study of the Effect of a Sol‐Gel Inorganic Network on Polymeric Relaxation Dynamics in Acrylic/Titania Hybrids

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