Solid state NMR and LVSEM studies on the hardening of latex modified tile mortar systems

Rottstegge, J.; Arnold, M.; Herschke, L.; Glaßer, Gunnar; Wilhelm, Manfred; Spiess, Hans Wolfgang; Hergeth, Wolf Dieter

doi:10.1016/j.cemconres.2004.10.003

Cited by 42 publications

(39 citation statements)

References 25 publications

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“…The glass transition temperatures (T g ) and the minimum film formation temperatures (MFT) of all of the latexes, listed in Table 2, were found to be below room temperature, and the latex particles were about 1 mm in diameter, for the redispersed powders, as reported elsewhere. [20] All of the samples listed above were provided by Wacker Polymer Systems. Nine different fiber samples with different polymer compositions, and different shapes and sizes, as summarized in Table 3, were chosen to reinforce the cement mixture.…”

Section: Investigated Samplesmentioning

confidence: 99%

“…[20] During hydration, latex particles covered the inorganic surfaces and formed an additional organic network. The applied latexes were, however, competing with the PVA and the methyl cellulose for the adsorption onto the inorganic surfaces.…”

Section: Fiber Latex and Cement Latex Compatibilitymentioning

confidence: 99%

“…Due to the low latex concentration of 2 to 3 wt.-%, no complete film formation could be observed among the inorganic components, but nevertheless the inorganic crystals stuck together, due to the latex acting as a glue. P(VAc-E)-1 and P(VAc-E-VeoVa) latexes were found to bind hydrated Rohrdorfer Portland cement crystals [20] and micro-cracks together. These micro-cracks caused by shear, to portlandite (Ca(OH) 2 ) for example, were connected by latex filaments and were easily visible within the hardened cement texture.…”

Section: Fiber Latex and Cement Latex Compatibilitymentioning

confidence: 99%

“…[20] Solid-state NMR spectroscopy [21][22][23][24] was applied to monitor the bulk composition of both the hardened cement and the polymer fibers, and its changes during the hydration process, while scanning electron microscopy [25,26] enabled the visualization of the fiber surfaces, and the particle shapes of the hydrated cement phases and the latex. Several contributions to the hydration and hardening of cement pastes, as determined from 1 H, 27 Al and 29 Si NMR spectroscopy [23,24,[27][28][29][30][31][32][33] and scanning electron microscopy, and of polymer-fiber-modified cements [7][8][9] are available in the literature, and are extended to a microscopic level. In particular the 27 Al NMR signals can be correlated to defined crystal structures within the inorganic phase.…”

Section: Introductionmentioning

confidence: 99%

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Compatibility Investigations on Polymer‐Fiber‐Reinforced Cements Modified with Polymer Latexes

Rottstegge

Han

Hergeth³

2006

Macro Materials & Eng

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Summary: In construction, polymer fibers are commonly applied beside steel, glass and mineral fibers to improve material's flexibility to shear stress. As in other composite systems, there are compatibility problems present between the fibers and the cement due to the different chemical natures and the different thermal expansion coefficients of the cement and the polymers. Within this study the interactions between two Portland cements and polymer fibers were investigated by SEM and solid‐state NMR spectroscopy. To improve the wetting ability of the polymer fibers by the cement matrix, redispersible latex powders were successfully applied to improve the adhesion between the cement matrix and the fibers. Within this study, several solid‐state nuclear magnetic resonance (NMR) spectroscopy methods, detecting 1H, 13C, 27Al and 29Si nuclei, and scanning electron microscopy (SEM) were applied. Thus, cement pastes, inorganic additives and organic admixtures could be monitored individually.SEM images of the interface between poly(propylene) fibers and Portland cement, hardened and hydrated in the presence of a 2 wt.‐% poly[(vinyl acetate)‐co‐ethylene] latex.magnified imageSEM images of the interface between poly(propylene) fibers and Portland cement, hardened and hydrated in the presence of a 2 wt.‐% poly[(vinyl acetate)‐co‐ethylene] latex.

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Section: Investigated Samplesmentioning

confidence: 99%

Section: Fiber Latex and Cement Latex Compatibilitymentioning

confidence: 99%

Section: Fiber Latex and Cement Latex Compatibilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Compatibility Investigations on Polymer‐Fiber‐Reinforced Cements Modified with Polymer Latexes

Rottstegge

Han

Hergeth³

2006

Macro Materials & Eng

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“…Besides, it has been described that adding polymer modifies the mineral assemblage of the cementitious matrix: the presence of polymer seems to reduce the amounts of both portlandite [16][17] and ettringite [18]. In this study, we characterized the calcium silicate hydrates (noted C-S-H) by 29 Si NMR and the aluminate hydrates by 27 Al NMR to assess the hydration processes in cement-polymer composites.…”

Section: Introductionmentioning

confidence: 99%

Cement-Polymer Composites for Oilwell Cementing

Chougnet

Audibert‐Hayet

Moan

et al. 2009

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Composites ciment-polymère pour la cimentation des puits pétroliers -La durabilité des matériaux utilisés pour les sondages pétroliers est une question essentielle pour garantir l'étanchéité à long terme des puits. Des composites ciment/polymère présentent de bonnes propriétés mécaniques et de durabilité : il est en effet connu que l'ajout de latex améliore l'adhésion ou la flexibilité des pâtes de ciment durcies. Ainsi, des composites ciment/polymère apparaissent comme de bons matériaux de cimentation de puits dans des environnements sévères. Lors de la construction d'un puits, le placement du laitier de ciment dépend très fortement de ses propriétés rhéologiques. Dans cet article, nous avons étudié les propriétés rhéologiques de suspensions composites à base de ciment et de poudre de polymère : nous montrons que sous cisaillement oscillatoire, ces suspensions présentent une transition d'un état gélifié vers un état de type liquide. Le remplacement d'une partie des particules de ciment par des particules de polymère induit une baisse du module de conservation de l'état gel. La bonne dispersion des particules de polymères et leur forte affinité pour les grains de ciment ont été observées par microscopie électronique. Des expériences de spectroscopie RMN et de calorimétrie ont mis en évidence une influence de l'addition de particules de polymères sur les mécanismes d'hydratation et de durcissement de la matrice cimentaire. L'ensemble des résultats acquis a amélioré notre compréhension des relations entre la composition du coulis, son comportement rhéologique et les propriétés du matériau durci, ce qui nous a permit de formuler de nouveaux matériaux de cimentation. Abstract -Cement-Polymer Composites for Oilwell Cementing -The selection of an optimal cementitious material is critical to maintain zonal isolation for the lifetime of oil & gas or gas

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A Total Synthesis of Spirastrellolide A Methyl Ester

Andrejew

Benson

Schulthoff

et al. 2013

Chemistry A European J

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A concise total synthesis of spirastrellolide A methyl ester (1 a, R(1) =Me) as the parent compound of a series of highly cytotoxic marine macrolides is disclosed, which exploits and expands the flexibility of a synthesis plan previously developed by our group en route to the sister compound spirastrellolide F methyl ester (6 a, R(1) =Me). Key to success was the masking of the signature Δ(15,16) -bond of 1 a as a C16-carbonyl group until after the stereogenic center at C24 had been properly set by a highly selective hydrogenation of the C24 exo-methylene precursor 66. Conformational control over the macrocyclic frame allowed the proper stereochemical course to be dialed into this reduction process. The elaboration of the C16 ketone to the C15-C16 double bond was accomplished by a chemoselective alkenyl triflate formation followed by a palladium-catalyzed hydride delivery. The role of the ketone at C16 as a strategic design element is also evident up-stream of the key intermediate 66, the assembly of which hinged upon the addition of the polyfunctionalized dithiane 37 to the similarly elaborate aldehyde fragment 46. Other crucial steps of the total synthesis were an alkyl-Suzuki coupling and a Yamaguchi lactonization that allowed the Northern and the Southern sector of the target to be stitched together and the macrocyclic perimeter to be forged. The lateral chain comprising the remote C46 stereocenter was finally attached to the core region by a modified Julia-Kocienski olefination. The preparation of the individual building blocks led to some methodological spin-offs, amongst which the improved procedure for the N-O-bond cleavage of isoxazolines by zero-valent molybdenum and the ozonolysis of a double bond in the presence of other oxidation-prone functionality are most noteworthy. Preliminary biological data suggest that the entire carbon framework, that is the macrocyclic core plus the lateral chain, might be necessary for high cytotoxicity.

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Solid state NMR and LVSEM studies on the hardening of latex modified tile mortar systems

Cited by 42 publications

References 25 publications

Compatibility Investigations on Polymer‐Fiber‐Reinforced Cements Modified with Polymer Latexes

Compatibility Investigations on Polymer‐Fiber‐Reinforced Cements Modified with Polymer Latexes

Cement-Polymer Composites for Oilwell Cementing

A Total Synthesis of Spirastrellolide A Methyl Ester

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