Chemical effects of DCCA to the sol-gel reaction process

Uchida, Nozomu; Ishiyama, Nobuo; Kato, Zenji; Uematsu, Keizo

doi:10.1007/bf01151115

Cited by 36 publications

(18 citation statements)

References 6 publications

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“…Specifically, the weight ratio of the slurry components was modified as follows: 30% CEL2, 6% PVA, 10% EG, 54% water. The presence of EG, as previously reported in literature, should lead to the prevention of cracks formation during the drying process of the samples [11,30] and thus obtaining an increase of the mechanical properties.…”

Section: Scaffolds Preparationsupporting

confidence: 60%

High strength bioactive glass-ceramic scaffolds for bone regeneration

Brovarone

Baino

Verné

2008

J Mater Sci: Mater Med

114

137

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This research work is focused on the preparation of macroporous glass-ceramic scaffolds with high mechanical strength, equivalent with cancellous bone. The scaffolds were prepared using an open-cells polyurethane sponge as a template and glass powders belonging to the system SiO(2)-P(2)O(5)-CaO-MgO-Na(2)O-K(2)O. The glass, named as CEL2, was synthesized by a conventional melting-quenching route, ground and sieved to obtain powders of specific size. A slurry of CEL2 powders, polyvinyl alcohol (PVA) as a binder and water was prepared in order to coat, by a process of impregnation, the polymeric template. A thermal treatment was then used to remove the sponge and to sinter the glass powders, in order to obtain a replica of the template structure. The scaffolds were characterized by means of X-ray diffraction analysis, morphological observations, density measurements, volumetric shrinkage, image analysis, capillarity tests, mechanical tests and in vitro bioactivity evaluation.

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Section: Scaffolds Preparationsupporting

confidence: 60%

High strength bioactive glass-ceramic scaffolds for bone regeneration

Brovarone

Baino

Verné

2008

J Mater Sci: Mater Med

114

137

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“…In order to shorten the reaction times and to enhance the drying behaviour of the gel network, Drying Control Chemical Additives (DCCAs) are often added to the sol [3,4,5]. The most commonly used one is formamide [6,7].…”

Section: Introductionmentioning

confidence: 99%

Structural evolution of a formamide modified sol—Spectroscopic study

Viart

Nižňanský

Rehspringer

1997

J Sol-Gel Sci Technol

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Abstract.We investigated the influence of formamide on the acid-catalyzed sol-gel process at 40~ by Fourier transformed infrared spectroscopy. Two silica sols were studied: one containing formamide and one without. Following the time evolution of both the Si--O(H) stretching vibration at around 950 cm -1 and the Si--O(--Si) vibration between 1080 and 1200 cm -1, we were able to describe the structural evolution of each sol. We thus observed, in the case of the formamide containing sol, a peculiar two-step structural evolution which eventually resulted in a highly interconnected gel.

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“…The main cause of such a dual particle size might the complexity arising from the difference in the rate of particle gelation as well as the self-hydrolysis and condensation rates of PMHS, depending on the concentration of either NaOH or K2HPO4.3H2O. On the other hand, the mean particle size of the sample increased with increasing NaOH concentration [29,30]. At higher NaOH concentrations (PS5), the particle size of the superhydrophobic powder increased to a micrometer size (Figure 4A, Table 2).…”

Section: Resultsmentioning

confidence: 99%

“…Dynamic light scattering (DLS, Zeta sizer, Nano S90) was used to measure the particle size of the samples. Before the measurements, the superhydrophobic powder was dispersed well in ethanol for 24 h. The functional groups present in the superhydrophobic powder were analyzed by Fourier transform infrared (FTIR, JASCO (FTIR-4100)) spectroscopy and 29 Si cross polarization magic angle spinning nuclear magnetic resonance ( 29Si CP MAS NMR) spectroscopy using a 400 MHz Avance II+ Bruker Solid-state NMR at the Korea Basic Science Institute (KBSI) Daegu Centre. The thermal stability of the superhydrophobic powder was estimated by thermogravimetric analysis (TGA, Q50 V6.2, Build 187, TA instruments, U.S) in a nitrogen atmosphere at a heating rate at 10 °C/min.…”

Section: Characterizationmentioning

confidence: 99%

Effect of Sodium Hydroxide on the Fast Synthesis of Superhydro-phobic Powder from Polymethylhydrosiloxane

Nagappan

2014

J. Coat. Sci. Technol.

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The paper reports the role of sodium hydroxide in the synthesis of a superhydrophobic powder from polymethylhydrosiloxane (PMHS) in the presence of ethanol and water. The effects of other basic and acidic solutions as well as the absence of water were also investigated. PMHS exhibited rapid gelation (from 8 h to 2 h) by increasing the concentration of sodium hydroxide in the presence of ethanol and water. In contrast, gelation did not occur in the absence of sodium hydroxide or water or in the presence of acidic solutions. Delayed gelation (96 h to 120 h) occurred as a result of the introduction of dipotassium hydrogen phosphate trihydrate. Superhydrophobic powder was obtained by the evaporation of solvents from the gelated sol at 150 °C. The surface properties of the superhydrophobic powder were examined by scanning electron microscopy, high resolution transmission electron microscopy, N2 sorption isotherm, and X-ray diffraction. The particle size, functional groups and thermal stability of the powder were analyzed by dynamic light scattering spectroscopy, Fourier transform infrared spectroscopy, 29 Si cross polarization magic angle spinning nuclear magnetic resonance spectroscopy, and thermogravimetric analysis. The surface properties of the powder were also assessed by contact angle measurements. The results showed that increasing the concentration of sodium hydroxide added to PMHS or increasing the drying temperature of the gelated sol resulted in the more rapid formation of superhydrophobic powder.

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Chemical effects of DCCA to the sol-gel reaction process

Cited by 36 publications

References 6 publications

High strength bioactive glass-ceramic scaffolds for bone regeneration

High strength bioactive glass-ceramic scaffolds for bone regeneration

Structural evolution of a formamide modified sol—Spectroscopic study

Effect of Sodium Hydroxide on the Fast Synthesis of Superhydro-phobic Powder from Polymethylhydrosiloxane

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