WO1999050203A1 - Controle chimique de la porosite d'une ceramique au moyen de carboxylate-alumoxanes - Google Patents

Controle chimique de la porosite d'une ceramique au moyen de carboxylate-alumoxanes Download PDF

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WO1999050203A1
WO1999050203A1 PCT/US1999/006137 US9906137W WO9950203A1 WO 1999050203 A1 WO1999050203 A1 WO 1999050203A1 US 9906137 W US9906137 W US 9906137W WO 9950203 A1 WO9950203 A1 WO 9950203A1
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carboxylate
alumoxane
boehmite
ceramic body
acid
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PCT/US1999/006137
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English (en)
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Rhonda Lynn Callender
Christopher Daniel Jones
Andrew Ross Barron
Diane Amy Bailey
Mark Robert Wiesner
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Wm Marsh Rice University
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Priority to CA002327097A priority Critical patent/CA2327097A1/fr
Priority to AU31958/99A priority patent/AU3195899A/en
Priority to EP99914011A priority patent/EP1070029A1/fr
Publication of WO1999050203A1 publication Critical patent/WO1999050203A1/fr
Priority to US09/670,230 priority patent/US6936306B1/en

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Definitions

  • the present invention relates generally to compositions of matter and methods for synthesizing a composition of matter including controlling the pore size, pore size distribution and porosity of aluminum-oxide based ceramics through the choice of substituents on carboxylate-alumoxanes and aluminum-oxide nanoparticles.
  • the invention includes aluminum and aluminum oxide ceramic bodies with intra-granular pores in the nanometer range and methods for forming intra-granular pores in the nanometer range in alumina and aluminum oxide ceramic bodies.
  • the invention provides for the control over pore size and pore size distribution by the use of chemical substituents on the carboxylate-alumoxanes and aluminum-oxide nanoparticles.
  • the invention also includes the use of controlled-porosity ceramics for ceramic membrane filters and coatings and interphase layers for fibers and fiber reinforced composites.
  • the oxides and hydroxides of aluminum are undoubtedly among the most industrially important chemicals. Their uses include: precursors for the production of aluminum metal, catalysts and absorbents; structural ceramic materials; reinforcing agents for plastics and rubbers, antacids and binders for the pharmaceutical industry; and as low dielectric loss insulators in the electronics industry.
  • Traditional ceramic processing involves three basic steps generally referred to as powder-processing, shape-forming, and densification, often with a final mechanical finishing step (Kingery et al. 1976 and Richerson 1992).
  • solution-gelation processes have been applied industrially used for the production of porous materials and coatings.
  • Solution-gelation involves a four stage process: dispersion; gelation; drying; and firing.
  • a stable liquid dispersion or sol of the colloidal ceramic precursor is initially formed in a solvent with appropriate additives.
  • the dispersion is polymerized to form a solid dispersion or gel.
  • the excess liquid is removed from this gel by drying, and the final ceramic is formed by firing the gel at higher temperatures.
  • the common solution-gelation route to aluminum oxides employs aluminum hydroxide (or hydroxide-based material) as the solid colloid, with the second phase being water and/or an organic solvent.
  • Aluminum hydroxide gels have traditionally been prepared by the neutralization of a concentrated aluminum salt solution (Serna et al. 1977), however, the strong interactions of the freshly precipitated alumina gels with ions from the precursor solutions makes it difficult to prepare these gels in pure form (Green and Hem 1974). To avoid this complication alumina gels may be prepared from the hydrolysis of aluminum alkoxides, Al(OR) 3 (Eq. 1).
  • the aluminum based sol-gels formed during the hydrolysis of aluminum compounds belong to a general class of compounds, namely alumoxanes. These materials were first reported in 1958 (Andrianov and Zhadanov, 1958) with siloxide substituents, however, they have since been prepared with a wide variety of substituents on aluminum. Recent work has shown that the structure of alumoxanes is as three dimensional cage compounds (Apblett et al. 1992 and Landry et al. 1993). For example, siloxy-alumoxanes, [Al(O)(OH) x (OSiR3) ⁇ .
  • Carboxylate-substituted alumoxanes have been well characterized (Landry et al. 1995 and Callender et al. 1997). Solution particle-size measurements shows that carboxylate-alumoxanes are nano-particles with sizes ordinarily ranging from 1 - 1000 nm ( Figure 10, 11 and 12). Nano- particles are ordinarily defined as materials with sizes ranging from 1 nm to 1 ⁇ m. The carboxylate ligand is bound to the aluminum surface, and is only removed under extreme conditions. The carboxylate-alumoxane materials prepared from the reaction of boehmite and carboxylic acids are air and water stable materials and are easily processable (Figure 7).
  • the soluble carboxylate-alumoxanes can be dip-coated, spin coated, and spray-coated onto various substrates.
  • the physical properties of these alumoxanes are highly dependent on the identity of the alkyl substituents, R, and range from those associated with insoluble crystalline powders to powders that readily form solutions or gels in hydrocarbon solvents and/or water.
  • These alumoxanes are indefinitely stable under ambient conditions, and are adaptable to a wide range of processing techniques.
  • the alumoxanes can be easily converted to aluminum oxide upon mild thermolysis, while they also react with metal complexes to form doped or mixed aluminum oxides (Kareiva et al. 1996).
  • porosity pore size, pore size distribution and pore density
  • Lower porosity improves strength, load-bearing capacity, and corrosion resistance, but can also lead to catastrophic failure from thermal shock, because the pores present
  • the pore size, pore size distribution and porosity are functions of the ceramic particles used to make the ceramic body, because the porosity is determined by the gaps between the individual particles ( Figure 4) and is therefore inter-granular, that is between the crystal grains. For example, pores below 0J ⁇ m in diameter require that submicron powders be used (in traditional ceramic processing),, while smaller pores require sol-gel processing.
  • Fiber reinforced ceramic matrix composites are potential candidates for use in high temperature structural applications (Courtright, 1991).
  • aerospace applications include high thrust-to-weight ratio gas turbine engines and high-specific- impulse rocket motors.
  • Ground based applications include high efficiency turbine and diesel engines.
  • FRCMCs have higher strengths at lower densities, higher maximum use temperatures, and better oxidation resistance.
  • FRCMCs fiber reinforced ceramic matrix composites
  • the fiber-matrix interface must be sufficiently weak to allow debonding and sliding when a crack impinges upon it from the matrix; otherwise the crack passes through the fiber (or the fiber fails near the crack tip) and there is minimal or no toughening (Michalke and Hellmann, 1988).
  • control of pore size, pore size distribution and porosity in ceramics is important for their applications in ceramic membranes and catalyst supports.
  • Membrane-based technologies play a unique and increasingly important role in pollution prevention, resource recovery and waste treatment activities (Baker, 1991). Due in large part to cost considerations, polymeric membranes have dominated these environmental separations applications.
  • Membrane characteristics as well as the properties of the contaminants can be manipulated through adjustments in the solution chemistry of the feed stream in one or more pretreatment steps (Anderson et al. 1988).
  • Ceramic membranes are typically produced by slip casting a colloidal suspension on a porous ceramic support: Okubo, et al. (1990), Elaloui et al. (1997), Lin et al. (1991), Lao et al. (1994), Zaspalis et al. (1992).
  • a schematic view of a typical membrane design is shown in Figure 5. The individual membranes are mounted into a membrane module (see Figure 6). Control of the colloidal suspension in the sol-gel process and limitations on the size of colloids that can be produced have constrained the range of membrane types that can be produced.
  • the membrane selectivity is primarily dependent upon the pore-size distribution: a narrow distribution contributes to a highly selective membrane.
  • Membrane permeability is a function of global porosity, membrane thickness, connectivity, and pore-size distribution.
  • Membrane durability is obtained by high homogeneity and high density; the latter entails a clear compromise with permeability.
  • Mechanical integrity is enhanced in such application by slip-casting a relatively thin selective membrane onto a larger, durable membrane of poor selectivity but high permeability.
  • the present invention provides alumina and aluminum-oxide ceramic membranes filters of controlled pore size, pore size distribution and porosity, a method to produce such filters, and the use of these materials as ceramic membrane filters.
  • the inventive method is based on the use of carboxylate-alumoxanes that can be described by the general formula: [Al(O) x (OH)y( ⁇ 2CR) z ] ⁇ and/or [Al(O) x (OH) y (O 2 CR) z (O 2 CR) z .] n and/or
  • RCO2" (and RCO2 " and R”CO 2 ") are mono-carboxylates and R (and R' and R") are the same or different and are from the group of a hydrogen and/or an organic group.
  • the organic group is preferably an alkyl, alkenyl, aromatic, haloalkyl, haloalkenyl, haloaromatic groups or alkyl, alkenyl, aromatic ether groups or an organic group containing a hetero-atom including, oxygen, nitrogen, sulfur, phosphorous.
  • These components may be prepared by the methods described in Landry et al. (1995), Apblett et al. (1992), Kareiva et al. (1996), and the preferred method of Callender et al. (1997).
  • the composition of the carboxylate-alumoxane varies depending on the starting materials employed and the details of the synthetic method employed by Callender et al. (1997). Thermolysis of the carboxylate-alumoxanes results in alumina being formed.
  • the size and distribution of pores within the alumina-oxide ceramic is dependent on the identity of the carboxylate substituents. In particular, the formation of intra- versus inter-granular porosity is dependent on the identity of the carboxylate substituents. Similarly, size and distribution of the pores is controlled by the choice of the organic substituents.
  • the invention also provides methods for the manufacture of ceramic coatings on ceramic and carbon fibers for composite applications and ceramic membranes with nanometer sized pores. Dipping a ceramic or carbon fiber into a solution of the carboxylate-alumoxane in accordance with the invention, drying and firing provides a uniform coating of the aluminum- oxide based ceramic on the surface of the fiber.
  • the pore size, pore size distribution and porosity, and hence the strength, permeability and surface adhesion of the ceramic coating is controlled by the choice of the substituent on the carboxylate-alumoxane.
  • Thermolysis of self-supporting spun layers of the carboxylate-alumoxanes results in disks of alumina with controlled pore size, pore size distribution and porosity.
  • a porous substrate may be dipped or coated with a solution of the carboxylate-alumoxane, followed by thermolysis to produce a composite membrane.
  • the present invention includes a ceramic body of controlled pore size and distribution comprising the thermolysis product of a carboxylate- alumoxane represented by the formula [Al(O) x (OH) y (O2CR) z ] n; wherein x is from 0 to 1.5, y is from 0 to 3, z is from 0 to 3, n is greater than 6, and R is hydrogen or an organic group.
  • a carboxylate- alumoxane represented by the formula [Al(O) x (OH) y (O2CR) z ] n; wherein x is from 0 to 1.5, y is from 0 to 3, z is from 0 to 3, n is greater than 6, and R is hydrogen or an organic group.
  • the invention includes a ceramic body of controlled pore size and distribution comprising the thermolysis products of a carboxylate-alumoxane represented by the formula [Al(O) x (OH)y( ⁇ 2CR) z ( ⁇ 2CR') z ']n, wherein x is from 0 to 1.5, y is from 0 to 3, z is from 0 to 3, z* is from 0 to 3, n is greater than 6, wherein each R, which may be the same or different, is hydrogen or an organic group, and wherein each R', which may be the same or different, is hydrogen or an organic group.
  • a carboxylate-alumoxane represented by the formula [Al(O) x (OH)y( ⁇ 2CR) z ( ⁇ 2CR') z ']n, wherein x is from 0 to 1.5, y is from 0 to 3, z is from 0 to 3, z* is from 0 to 3, n is greater than 6, wherein each R, which may be the
  • the invention includes a porous ceramic body comprising the thermolysis product of the reaction product of a carboxylic acid with boehmite, represented by the formula [Al(O) x (OH) y (O2CR) z ] n , wherein the porosity and pore size distribution of the ceramic body is controlled by the selection of the number, z, of carboxylate groups.
  • the invention includes a porous ceramic composite comprising a nano-particle comprising the thermolysis product of the reaction product of a substituted carboxylate-alumoxane with an aluminum oxide wherein the pore size and pore distribution of the ceramic composite are controlled by the substituent on the carboxylate- alumoxane.
  • the invention includes a porous ceramic filter of controlled pore size and pore size distribution comprising a nano-particle comprising the thermolysis product of the reaction product of a substituted carboxylate-alumoxane with an aluminum oxide wherein the pore size and pore distribution of the ceramic composite are controlled by the substituent on the carboxylate-alumoxane.
  • the invention includes a fiber reinforced material comprising a fiber, and a fiber coating comprising a porous ceramic composite of a nano-particle comprising the thermolysis product of the reaction product of a substituted carboxylate- alumoxane with an aluminum oxide wherein the pore size and pore distribution of the ceramic composite are controlled by the substituent on the carboxylate-alumoxane.
  • the invention includes a method of controlling the porosity and pore size distribution of ceramic bodies comprising: reacting boehmite with a carboxylic acid to produce carboxylate-alumoxane nanoparticles; drying the carboxylate- alumoxane nano-particles; re-dissolving the carboxylate-alumoxane nano-particles in a solvent; drying the nano-particles; andfiring the dried nano-particles at a temperature greater than 300 °C.
  • Figure 1 is a schematic representation of the core of an alumoxane sol-gel material
  • Figure 2 is a schematic representation of the periphery of a typical siloxide-alumoxane
  • Figure 3 is a schematic representation of the periphery of a carboxylate-alumoxane
  • Figure 4 is a schematic representation of a typical spacer ligand
  • Figure 5 is schematic representation of intergranular porosity
  • Figure 6 is a another schematic representation of intergranular porosity
  • Figure 7 is a pictorial representation of the reaction of boehmite with carboxylic acids
  • Figure 8 illustrates thermal processing of alumoxanes by a controlled heating series
  • Figure 9 illustrates a model for inter-granular versus intra-granular porosity
  • Figure 10 illustrates particle size determination by Photon Correlation Spectroscopy (PCS);
  • Figure 11 is a graphical representation of particle size determination of carboxylate- alumoxanes in water by PCS;
  • Figure 12 is a graphical representation of particle size determination of various aliquots removed from the reaction of MEA-H with boehmite by PCS;
  • Figure 13 shows Transmission Electron Microscopy (TEM) images of ⁇ -Al O 3 from carboxylate-alumoxanes
  • Figure 14 is a TEM image of Al 2 O 3 ceramic material from fired acetate-alumoxane
  • Figure 15 shows TEM negative images of fired acetate-alumoxane illustrating intra- granular pores
  • Figure 16 shows images of fired acetate-alumoxane illustrating intragranular porosity
  • Figure 17 is a Selected Area Diffraction (SAD) image of fired acetate-alumoxane ceramic material
  • Figure 18 shows surface images of mixed carboxylate-alumoxanes
  • Figure 19 is a schematic representation of the method of formation of a membrane
  • Figure 20 is a schematic representation of the structure of a filter-supported membrane
  • Figure 21 is a SEM image of a coated frit
  • Figure 22 shows micrographs of coated carbon fibers
  • Figure 23 shows a micrograph of a hibonite coated silicon carbide fiber
  • Figure 24 shows micrographs of coated and uncoated sapphire fibers
  • Figure 25 is a schematic representation of a mixed-ligand alumoxane
  • Figure 26 is a bar chart comparing the pore size distributions of two carboxylate alumoxanes and a physical mixture of two carboxylate alumoxanes
  • Figure 27 is a bar chart comparing the pore size distributions of two carboxylate alumoxanes and a chemical mixture of two carboxylate alumoxanes.
  • This invention discloses the use of carboxylate-alumoxanes ([Al(O) x (OH) y (O2CR) z ] n ) and/or aluminum-oxide nano-particles to prepare alumina and aluminum oxide-based ceramic bodies, coatings and membranes with chemically controlled pore sizes, pore size distributions and porosities.
  • Such ceramics with chemically controlled porosities may be used as membrane materials with controlled pore size distributions or as coatings on fibers.
  • the carboxylato-alumoxanes are precursors to alumina and aluminum oxides (Table 1) and are prepared by the reaction of boehmite or pseudoboehmite with carboxylic acids in a suitable solvent (Tables 2, 3, 4, and 5).
  • the boehmite (or pseudoboehmite) source can be a commercial boehmite product such as Catapal (A, B, C, D, or FI, Vista Chemical Company) or boehmite prepared by the precipitation of aluminum nitrate with ammonium hydroxide and then hydrothermally treated at 200 °C for 24 hours or boehmite prepared by the hydrolysis of aluminum trialkoxides followed by hydrothermal treatment at 200 °C.
  • the carboxylic acid can be any monocarboxylic acid.
  • the carboxylic acid can be aromatic, aliphatic, and can contain hetero- atom functional groups such as hydroxyls, amines, mercaptans, phosphines, etc.
  • the carboxylate alumoxanes are stable both in solution and the solid state.
  • the solubility of the carboxylate alumoxanes is dependent only on the identity of the carboxylic acid residue, which is almost unrestricted according to the present invention. The solubility of the alumoxanes is therefore readily controlled so as to make them compatible with any co-reactants.
  • the alumoxanes have yet further benefits with respect to large scale production of ternary and quaternary ceramics.
  • the most dramatic of these is the simplicity of the alumoxane methodology.
  • the alumoxane route is simple, and can be halted and/or modified at any stage without significant effects on the products.
  • a careful control of pH, the use of additives to inhibit precipitation, and slow concentration steps are not required, thus making the alumoxane route easier and quicker than prior art techniques.
  • Another benefit with respect to large scale processing is the relatively low cost of the alumoxane precursors.
  • Thermogravimetric/differential thermal analysis (TG/DTA) of the carboxylate- alumoxanes generally indicates two major decomposition regions. The relative mass loss and temperatures at which these regions occur is dependent on the identity of the carboxylic acid. The volatiles are predominantly the carboxylic acid and water, with traces of the ketone, i.e., acetone is liberated from the acetate-alumoxane (A-alumoxane or A- A). As may be expected, the ceramic yield is conditional on the identity of the carboxylic acid: greatest for A-A (ca. 75 %), lowest for methoxy(ethoxyethoxy)acetate-alumoxane (MEEA-A) (ca. 20 %). All of the carboxylate- alumoxanes decompose above 180 °C to give amorphous alumina. Firing above 900 °C (> 3 h.)
  • the ⁇ -Al 2 ⁇ 3 formed from MEEA-, MEA-, and MA- (methoxyacetate) alumoxanes exists as a nanocrystalline matrix with a very high volume of large interconnecting pores, as determined by TEM studies ( Figure 13).
  • analysis of the ⁇ -Al2 ⁇ 3 formed from A-alumoxane revealed very fine uniform intra-granular porosity (Figure 14), in which the crystallite size is relatively large (ca. 2 ⁇ m).
  • the difference in pore size and structure is more consistent with the chemical identity of the substituents than the physical processing conditions, i.e., a higher organic volume outgassed produces larger pores.
  • alumoxane series it is possible to engineer pore size continuously between these extremes by using mixed ligand solutions (Figure 25).
  • A-alumoxane acetate-alumoxane
  • the pores are intra-granular, that is, they are within the individual crystal grains ( Figure 6).
  • This novelty of chemical control over the formation of intra- granular (rather than inter-granular) porosity has the aforementioned benefit of increased fracture toughness.
  • Intra-granular pores instead of inter-granular therefore allow increased fracture toughness and less opportunity for pore/boundary/crack interactions to occur.
  • the formation of intra-granular pores for the A-alumoxane is thought to be due to the nano-particulate nature of
  • Control of pore size, pore size distribution and porosity, and hence density, through chemical means is an important departure from traditional ceramic processing in which physical methods only are applied.
  • the porosity of the resulting alumina is dependent on the length of the carboxylate side chain. That is, the pore sizes for carboxylate-alumoxanes with CH3 substituents is different from those with C5H11 substituents.
  • Another approach to controlling pore size, pore size distribution and porosity described herein is the use of spacer ligands.
  • the alumoxane can be cross-linked after fabrication of the membrane with di-acids ( Figure 4). Upon pyrolysis, it then inhibits the collapse of the ceramic.
  • a physical mixture of more than one carboxylate-alumoxane may be produced and fired to alumina (Tables 4, 5, 6 and 7).
  • the porosity (average pore size and pore size distribution) is dependent on the relative amounts of each carboxylate-alumoxane (Table 8). In general, the porosity is a mixture of the values of each individual carboxylate-alumoxane ( Figures 26 and 27).
  • Mixed carboxylate-alumoxanes may be synthesized in which more than one type of carboxylate group is bonded to each of the alumoxane nano-particles.
  • the resulting porosity is different than the individual materials, and is dependent on the relative concentration of each carboxylate used (Table 8).
  • the relative intra- to inter-granular porosity can be controlled by the choice of carboxylate group and/or mixtures or carboxylate groups.
  • a porous substrate such as a glass or ceramic filter frit may be spun coated, painted, or dip-coated with the carboxylate-alumoxane solution, Figure 21 (Tables 9 and 10). After drying and firing the composite consists of a membrane supported on a coarse filter ( Figure 20).
  • the support for the carboxylate-alumoxane derived ceramic membrane does not have to be flat but may be a ceramic tube or column. If doped carboxylate-alumoxanes are employed, then the resulting membrane will have the composition of the doped carboxylate-alumoxane. In order to ensure that uniform membranes are produced, physical mixtures of different carboxylate-alumoxanes can be used. The lowering of phase formation/crystal growth temperatures observed for the carboxylate-alumoxane in
  • Carbon or ceramic fibers can also be dipped or coated with a solution of the carboxylate- alumoxanes ( Figures 22, 23, and 24). After drying either in air, in an oven or with a heat gun, the carboxylate-alumoxane can be thermolyzed to give the appropriate ceramic coating with a chemically controlled porosity.
  • Suitable ceramic fibers include (but are not limited to) silicon carbide ( Figure 23) and sapphire ( Figure 24). The conditions of thermolysis of the alumoxane coating are dependent on the type of the fiber and the identity of the carboxylate-alumoxane.
  • the ceramic coatings produced using the carboxylate-alumoxanes show superior coverage, better uniformity, and lower defects than found for sol-gel type coatings, due to the nano-particle nature of the carboxylate-alumoxane. Furthermore, the lowering of phase formation/crystal growth temperatures observed for the carboxylate-alumoxane allow for less damage to the fiber substrate during formation of the ceramic coating.
  • EXAMPLES Surface area and pore size analysis were conducted on all samples utilizing a Coulter SA
  • Sample tubes used are all Coulter Rapi-tubes. Samples were outgassed at 350 °C for 3 hours under nitrogen gas on the SA 3100. All sample masses were in the 0J00 g to 0J90 g range. For actual analysis, nitrogen gas was also used as the absorbate and helium gas was used to measure the free-space in the sample tube. BET surface area was determined using 5 data points. The t-plot method was determined utilizing the Harkins-Jura equation at normal resolution. BJH parameters were determined using medium (45 data points) resolution and the equation used was Harkins-Jura. Pore size distributions (and weighted averages) are reported as a function of the BJH adsorption.
  • AFM images of samples were obtained using a Nanoscope Ilia Scanning Probe Microscope, (Digital Instruments, Santa Barbara, CA) in tapping mode AFM.
  • FESP tips were used with a pyramidal shape and end radius of 5 - 10 nm (also from Digital Instruments). Images were taken at scan sizes of 10 ⁇ m, 1 ⁇ m, and 200 nm, and the scan angle was changed from 0 to 45° to check the integrity of the images. Images were later processed to obtain roughness, grain size, and section analysis with the accompanying Nanoscope software. Permeability was derived from Flux experiments using dead end filtration cells from Spectrum and Sartorious. The cells were 400 mL and 200 mL (respectively) and were connected to a tank of zero-air for positive pressure.
  • a pressure regulator was used to set constant pressure for each flux experiment at 10, 20, or 30 psi, and filtrate was collected in beakers and measured volumetrically. Ultrapure deionized water was used, obtained from a Milli-Q water filter. Membrane samples were epoxied to precut aluminum foil disks with precut holes in the center, of known area, matching each membrane piece. The membrane pieces had an area between 0.5
  • Membranes were crushed with a mortar and pestle and combined with sodium chloride as an electrolyte to form a 500 mg.L -1 alumoxane and 500 mg.L -1 NaCl solution.
  • the solutions were set at various pHs using HC1 or NaOH, and electrophoretic mobility and zeta potential were measured at several different voltages.
  • Example 1 Synthesis of methoxy(ethoxyethoxy)acetate-alumoxane (MEEA-A).
  • Pseudoboehmite (20.0 g) and methoxy(ethoxyethoxy)acetic acid (102 mL) were refluxed in water (400 mL) resulting in a clear solution after 72 h.
  • the solution was centrifuged at 6000 rpm for 1 hour and decanted. Removal of the volatiles in vacuo (10 -2 Torr) at 90 °C yielded a gel which was then dissolved in ethanol (100 mL) while stirring (10 min.) then triturated with diethyl ether (200 mL).
  • the white solid powder thus obtained was redissolved in water (100 mL) and dried at 50 °C for 24 h resulting in a clear glassy material.
  • the MEEA-alumoxane is soluble in water, methanol, chloroform, and methylene chloride.
  • the alumoxane was heated from 25 °C to 225 °C at the rate of l°C/min., soaked for 30 mins. at 225 °C, followed by a temperature ramp up to 300 °C at the rate of 2 °C/min., and soaked for 80 mins., with a final ramp to the maximum temperature of 1100°C (over 360 minutes) which was then maintained for 400 minutes (Figure 8).
  • Example 2 Synthesis of methoxy(ethoxyethoxy)acetate-alumoxane.
  • Methoxy(ethoxyethoxy)acetic acid 60 mL was dissolved in 300 mL of water and Vista Captal B boehmite (12 g) was slowly added and allowed to reflux for 96 hours. The clear/yellow solution was filtered and the filtrate was evaporated under reduced pressure to a yellow gel. The gel was dissolved in ethanol and the white/yellow powder product was obtained upon addition of diethyl ether. Yield: 13.6 g.
  • the TGA of the methoxy(ethoxy)acetate-alumoxane showed 22.3% ceramic yield (weight loss of 77.7% ). The alumoxane was heated from 25 °C to 200 °C at the
  • Example 3 Synthesis of Methoxy(ethoxy)acetate-alumoxane (MEA-A).
  • Pseudoboehmite (10.0 g) and methoxy(ethoxy)acetic acid (38.0 mL) were refluxed in water (100 mL) for 24 h, resulting in a clear solution.
  • the solution was centrifuged at 6000 rpm for 1 h and decanted.
  • the water was removed in vacuo (10" 2 Torr) at 50 °C, resulting in a gel.
  • the gel was washed with Et2 ⁇ (3 x 75 mL) then dissolved in EtOH (50 mL) while stirring (10 minutes).
  • the MEA-alumoxane was precipitated via the addition of Et2 ⁇ (100 mL) as a white powder.
  • the powder was dissolved in water (100 mL), isolated by filtration, concentrated under vacuum and dried at 50°C resulting in a white solid material.
  • the alumoxane was heated from 25 °C to 225 °C at the rate of l°C/min., soaked for 30 mins. at 225 °C, followed by a temperature ramp up to 300 °C at the rate of 2 °C/min., and soaked for 80 mins., with a final ramp to the maximum temperature of 1100°C (over 360 minutes) which was then maintained for 400 minutes.
  • Pseudoboehmite (20.0 g) was slowly added to a vigorously stirring mixture of acetic acid (51.0 mL) in water (200 mL). The resulting slurry was decanted after 10 minutes and then centrifuged at 6000 rpm for 1 hour to yield a clear viscous solution. Removal of the volatiles in vacuo (10" 2 Torr) at 90°C results in clear, white granules. The granules were dissolved in water and dried for 24 hours at 80 °C to yield a clear glassy material. The alumoxane was heated from 25 °C to 225 °C at the rate of l°C/min., soaked for 30 mins.
  • the alumoxane was heated from 25 °C to 200 °C at the rate of 1.5 0 C.min _1 , soaked for 2 h. at 200 °C, followed by a temperature ramp up to 1000 °C at the rate of 5 °C.min- 1 , soaked for 2 h.
  • Example 8 Synthesis of Acetate-alumoxane.
  • Example 12 Synthesis of Malonate-alumoxane. Prepared in an analogous manner to that in Example 10 with the amounts and conditions shown in Table 3.
  • Example 13 Synthesis of Malonate-alumoxane.
  • Example 14 Synthesis of mixed ligand methoxy(ethoxy)acetate-acetate-ah ⁇ moxane.
  • Example 15 Synthesis of mixed ligand methoxy(ethoxy)acetate-acetate-alumoxane. Prepared in an analogous manner to that in Example 14 with the amounts and conditions shown in Table 4.
  • Example 16 Synthesis of mixed ligand methoxy(ethoxy)acetate-acetate-alumoxane.
  • Example 17 Synthesis of mixed ligand methoxy(ethoxy)acetate-acetate-alumoxane.
  • Example 18 Synthesis of mixed ligand methoxy(ethoxy)acetate-acetate-alumoxane.
  • Example 19 Synthesis of mixed ligand methoxy(ethoxy)acetate-acetate-alumoxane.
  • Example 20 Synthesis of mixed ligand methoxy(ethoxyethoxy)acetate-acetate-alumoxane.
  • Acetic acid (28.6 mL) and methoxy(ethoxyethoxy) acetic acid (76J mL) was dissolved in 500 mL of water and Vista Captal B boehmite (20 g) was slowly added and the solution was allowed to reflux for 72 hours. The solution was filtered and the filtrate was evaporated under reduced pressure resulting in a white/clear gel. The gel was dissolved in ethanol and the product was collected as a white powder upon the addition of diethyl ether. Yield: 25.4 g. The TGA of the product showed a 28.5 % ceramic yield (weight loss of 71.5%).
  • Example 21 Synthesis of mixed ligand methoxy(ethoxyethoxy)acetate-acetate-aIumoxane. Prepared in an analogous manner to that in Example 20 with the amounts and conditions shown in Table 5.
  • Example 22 Physical Mixing of methoxy(ethoxy)acetate-alumoxane (MEA-A) and acetate- alumoxane (A-A).
  • MEA-A 1.0 g
  • A-A 1.0 g
  • Example 24 Physical Mixing of methoxy(ethoxy)acetate-alumoxane (MEA-A) and acetate- alumoxane (A-A). Prepared in an analogous manner to that in Example 22 with the amounts and conditions shown in Table 6.
  • Example 25 Physical Mixing of methoxy(ethoxy)acetate-alumoxane (MEA-A) and acetate- alumoxane (A-A).
  • Example 26 Physical Mixing of chemically mixed methoxy(ethoxyethoxy)acetate-acetate- alumoxane (MEA/A-A) and acetate-alumoxane (A-A).
  • MEA/A-A chemically mixed methoxy(ethoxyethoxy)acetate-acetate- alumoxane
  • A-A acetate-alumoxane
  • MEA/A-A (1.0 g) and A-A (1.0 g) were dissolved into 20 mL of water. After stirring for approximately 0.5 hours the solutions were poured into drying containers. After approximately
  • Example 27 Physical Mixing of chemically mixed methoxy(ethoxyethoxy)acetate-acetate- alumoxane (MEA/A-A) and acetate-alumoxane (A-A). Prepared in an analogous manner to that in Example 26 with the amounts and conditions shown in Table 7.
  • Example 28 Physical Mixing of chemically mixed methoxy(ethoxyethoxy)acetate-acetate- alumoxane (MEA/A-A) and acetate-alumoxane (A-A).
  • MEA/A-A chemically mixed methoxy(ethoxyethoxy)acetate-acetate- alumoxane
  • A-A acetate-alumoxane
  • Example 29 Physical Mixing of chemically mixed methoxy(ethoxyethoxy)acetate-acetate- alumoxane (MEA/A-A) and acetate-alumoxane (A-A).
  • MEA/A-A chemically mixed methoxy(ethoxyethoxy)acetate-acetate- alumoxane
  • A-A acetate-alumoxane
  • Example 30 Physical Mixing of chemically mixed methoxy(ethoxyethoxy)acetate-acetate- alumoxane (MEA/A-A) and acetate-alumoxane (A-A).
  • Example 31 Infiltration of alumino-silicate filters.
  • a filter frit (pore size ca. 25 ⁇ m) was placed in a Schleck flask and evacuated.
  • a solution of A-A (10 g) in 100 mL of water was introduced into the Schlenk by canula under vacuum which resulted in the ceramic frit "soaking up" the alumoxane solution.
  • the frit was allowed to sit for approximately 0.5 hours under reduced pressure with an excess of the alumoxane solution covering the frit in the schlenk.
  • the frit was then allowed to dry at room temperature. The frit was then either infiltrated again, fired, or fired then infiltrated again.
  • Example 32 Infiltration of alumino-silicate filters.
  • Example 33 Infiltration of alumino-silicate filters. Prepared in an analogous manner to that in Example 31 with the number of infiltrations
  • Example 34 Infiltration of alumino-silicate filters.
  • Example 35 Infiltration of alumino-silicate filters.
  • Example 36 Infiltration of alumino-silicate filters. Prepared in an analogous manner to that in Example 31 with the number of infiltrations
  • Example 37 Infiltration of alumino-silicate filters.
  • Example 38 Infiltration of alumino-silicate filters.
  • Example 39 Infiltration of alumino-silicate filters.
  • Example 40 Infiltration of alumino-silicate filters.
  • Example 41 Infiltration of alumino-silicate filters. Prepared in an analogous manner to that in Example 31 with the number of infiltrations
  • Example 42 Infiltration of alumino-silicate filters.
  • Example 43 Infiltration of alumino-silicate filters.
  • Example 44 Infiltration of glass filters.
  • a glass filter frit (pore size D) was placed in a Schleck flask and evacuated.
  • a solution of A-A (10 g) in 100 mL of water was introduced into the Schlenk by canula under vacuum which resulted in the glass frit "soaking up" the alumoxane solution.
  • the frit was allowed to sit for approximately 0.5 hours under reduced pressure with an excess of the alumoxane solution covering the frit in the schlenk.
  • the frit was then allowed to dry at room temperature.
  • the infiltration was repeated twice.
  • the infiltrated glass frit was heated from 25 °C to 350 °C, analyzed by SEM, heated from 25 °C to 700 °C and analyzed.
  • Example 46 Infiltration of glass filters. Prepared in an analogous manner to that in Example 44 with the number of infiltrations
  • Example 47 Infiltration of glass filters.
  • Example 48 Preparation of alumina coated carbon fibers.
  • MEEA-alumoxane (0J g) was dissolved in CHCI3 (5 mL) at room temperature.
  • the fiber is dipped in MEEA-alumoxane solution and allowed to fully air dry, at room temperature. Repeat dipping/drying until desired coating thickness is obtained.
  • the coated fiber was heated from 25 °C to 225 °C at the rate of 1 °C.min- 1 , soaked for 30 mins. at 225 °C, followed by a temperature ramp up to 300 °C at the rate of 2 °C.min _1 , and soaked for 80 mins., with a final ramp to the maximum temperature of 1100 °C (over 360 minutes) which was then maintained for 400 minutes.
  • Example 49 Preparation of alumina coated carbon fibers.
  • Example 50 Preparation of alumina coated carbon fibers.
  • Example 51 Preparation of alumina coated carbon fibers. Prepared in an analogous manner to that in Example 48 using the amounts and conditions shown in Table 11.
  • Example 52 Preparation of alumina coated carbon fibers.
  • Example 53 Preparation of alumina coated carbon fibers.
  • MEEA-alumoxane (0J g) was dissolved in H2O (5 mL) with low heat (40 °C) and stirring. The fiber is dipped in MEEA-Alumoxane solution and allowed to partially dry at room temperature then dried in oven (45° C) for 24h. Repeat dipping/drying until desired coating thickness is obtained. The coated fiber was heated from 25 °C to 225 °C at the rate of 1 °C.min _1 ,
  • Example 54 Preparation of alumina coated carbon fibers. Prepared in an analogous manner to that in Example 53 using the amounts and conditions shown in Table 11.
  • Example 55 Preparation of alumina coated carbon fibers.
  • Example 56 Preparation of alumina coated carbon fibers.
  • Example 57 Preparation of alumina coated carbon fibers.
  • Example 58 Preparation of YAG coated carbon fibers.
  • Yttrium-doped MEEA-alumoxane (0.5 g) was dissolved in H2O (5 mL) with low heat (40 °C) and stirring. The fiber is dipped in the Y-doped MEEA-alumoxane solution and allowed to partially dry at room temperature then dried in oven (45° C) for 24h. Repeat dipping/drying until desired coating thickness is obtained. The coated fiber was heated from 25 °C to 225 °C at the rate of 1 "Cmiir 1 , soaked for 30 mins.
  • Example 59 Preparation of YAG coated carbon fibers. Prepared in an analogous manner to that in Example 58 using the amounts and conditions shown in Table 11.
  • Example 60 Preparation of YAG coated carbon fibers.
  • Example 61 Preparation of hibonite coated carbon fibers.
  • Calcium-doped MEEA-alumoxane (0.5 g) was dissolved in H 2 O (5 mL) with low heat (40 °C) and stirring. The fiber is dipped in the Ca-doped MEEA-alumoxane solution and allowed to partially dry at room temperature then dried in oven (45° C) for 24h. Repeat dipping/drying until desired coating thickness is obtained. The coated fiber was heated from 25 °C to 225 °C at
  • Example 62 Preparation of hibonite coated carbon fibers. Prepared in an analogous manner to that in Example 61 using the amounts and conditions shown in Table 11.
  • Example 63 Preparation of hibonite coated carbon fibers.
  • Example 64 Preparation of hibonite coated carbon fibers.
  • Calcium-doped MEEA-alumoxane (0J g) was dissolved in CHCI3 (5 mL) at room temperature.
  • the fiber is dipped in Ca-doped MEEA-alumoxane solution and allowed to fully air dry, at room temperature. Repeat dipping/drying until desired coating thickness is obtained.
  • the coated fiber was heated from 25 °C to 225 °C at the rate of 1 °C.min _1 , soaked for 30 mins. at 225 °C, followed by a temperature ramp up to 300 °C at the rate of 2 °C.min- 1 , and soaked for 80 mins., with a final ramp to the maximum temperature of 1100 °C (over 360 minutes) which was then maintained for 400 minutes.
  • Example 65 Preparation of hibonite coated carbon fibers.
  • Example 66 Preparation of hibonite coated carbon fibers.
  • Example 67 Preparation of hibonite silicon carbide fibers. Calcium-doped MEA-alumoxane (0J g) was dissolved in CHCI3 (5 mL) at room temperature. The SiC fiber was cleaned with acetone and dipped in a Ca-doped MEA-alumoxane solution and allowed to fully air dry, at room temperature. Repeat dipping/drying until desired coating thickness is obtained. The coated fiber was heated from 25 °C to 225 °C at the rate of 1
  • Example 68 Preparation of hibonite coated silicon carbide fibers.
  • Example 70 Preparation of hibonite coated silicon carbide fibers. Prepared in an analogous manner to that in Example 67 using the amounts and conditions shown in Table 12.
  • Example 71 Preparation of hibonite coated silicon carbide fibers.
  • Example 72 Preparation of hibonite coated silicon carbide fibers.
  • Example 73 Preparation of hibonite coated silicon carbide fibers.
  • Example 74 Preparation of hibonite silicon carbide fibers.
  • Calcium-doped MEA-alumoxane (0.5 g) was dissolved in H 2 O (5 mL) with low heat (40°C) and stirring.
  • the fiber is cleaned with acetone and dipped in a metal-doped MEA- alumoxane solution and allowed to partially dry at room temperature then dried in oven (45° C) for 24 h. Repeat dipping/drying until desired coating thickness is obtained.
  • the coated fiber was heated from 25 °C to 225 °C at the rate of 1 °C.min- 1 , soaked for 30 mins.
  • Example 75 Preparation of hibonite coated silicon carbide fibers.
  • Example 76 Preparation of hibonite coated silicon carbide fibers.
  • Example 77 Preparation of hibonite coated silicon carbide fibers.
  • Example 79 Preparation of hibonite sapphire fibers. Calcium-doped MEA-alumoxane (0J g) was dissolved in CHCI3 (5 mL) at room temperature. The sapphire fiber was cleaned with acetone and dipped in a Ca-doped MEA- alumoxane solution and allowed to fully air dry, at room temperature. Repeat dipping/drying until desired coating thickness is obtained. The coated fiber was heated from 25 °C to 225 °C at the rate of 1 °C.min" 1 , soaked for 30 mins.
  • Example 80 Preparation of hibonite coated sapphire fibers.
  • Example 81 Preparation of hibonite coated sapphire fibers.
  • Example 82 Preparation of hibonite coated sapphire fibers.
  • Example 83 Preparation of hibonite coated sapphire fibers.
  • Example 84 Preparation of hibonite coated sapphire fibers. Prepared in an analogous manner to that in Example 79 using the amounts and conditions shown in Table 13.
  • Example 85 Preparation of hibonite coated sapphire fibers.
  • Example 86 Preparation of hibonite sapphire fibers.
  • Example 87 Preparation of hibonite coated sapphire fibers. Prepared in an analogous manner to that in Example 86 using the amounts and conditions shown in Table 13. Example 88. Preparation of hibonite coated sapphire fibers.
  • Example 89 Preparation of hibonite coated sapphire fibers.
  • Example 90 Preparation of hibonite coated sapphire fibers.

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Abstract

L'invention concerne en général un procédé servant à contrôler la dimension des pores, la répartition de cette dimension et la porosité de céramiques à base d'oxyde d'aluminium et consistant à sélectionner des substituants de carboxylate-alumoxanes et de nanoparticules d'oxyde d'aluminium. Ce procédé permet d'obtenir des pores intragranulaires de l'ordre du nanomètre à créer dans des corps de céramique d'alumine et d'oxyde d'aluminium. On effectue le contrôle de la dimension des pores et de la répartition de cette dimension par l'intermédiaire de différents substituants chimiques des carboxylate-alumoxanes et des nanoparticules d'oxyde d'aluminium. La dimension et la répartition des pores à l'intérieur de la céramique d'oxyde d'aluminium dépend de l'identité des substituants de carboxylate. En particulier, la formation d'une porosité intragranulaire par rapport à une porosité intergranulaire dépend de l'identité des substituants de carboxylate. L'invention concerne également des procédés servant à fabriquer des revêtements de céramique sur des fibres de céramique et de carbone pour des mises en application composites et des membranes de céramique présentant des dimensions de pores de l'ordre du nanomètre. On contrôle la dimension des pores, la répartition de la dimension des spores, la porosité et, de ce fait, la résistance, la perméabilité et l'adhérence de surface du revêtement de céramique au moyen du choix du substituant de carboxylate-alumoxane. La thermolyse de couches centrifugées autonomes de ces carboxylate-alumoxanes permet d'obtenir des disques d'alumine dont la dimension de pores, la répartition de cette dimension et la porosité ont été contrôlées. Dans un autre mode de réalisation, on trempe un substrat poreux dans une solution de carboxylate-alumoxane ou on le revêt de cette solution, puis on le soumet à une thermolyse afin d'obtenir une membrane composite.
PCT/US1999/006137 1998-03-30 1999-03-26 Controle chimique de la porosite d'une ceramique au moyen de carboxylate-alumoxanes WO1999050203A1 (fr)

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CA002327097A CA2327097A1 (fr) 1998-03-30 1999-03-26 Controle chimique de la porosite d'une ceramique au moyen de carboxylate-alumoxanes
AU31958/99A AU3195899A (en) 1998-03-30 1999-03-26 Chemical control over ceramic porosity using carboxylate-alumoxanes
EP99914011A EP1070029A1 (fr) 1998-03-30 1999-03-26 Controle chimique de la porosite d'une ceramique au moyen de carboxylate-alumoxanes
US09/670,230 US6936306B1 (en) 1998-03-30 2000-09-28 Chemical control over ceramic porosity using carboxylate-alumoxanes

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US7992698P 1998-03-30 1998-03-30
US60/079,926 1998-03-30

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WO2002086194A2 (fr) * 2001-04-21 2002-10-31 Itn-Nanovation Gmbh Couches ceramiques fonctionnelles comprenant une couche support produite au moyen de nanoparticules cristallines
WO2003099979A1 (fr) * 2002-05-24 2003-12-04 The Procter & Gamble Company Composition, necessaire et procede de nettoyage et/ou de traitement de surfaces
US6710005B1 (en) * 2003-04-10 2004-03-23 Equistar Chemicals, Lp Aluminoxane modification
US6887517B1 (en) 2002-06-12 2005-05-03 Tda Research Surface modified particles by multi-step Michael-type addition and process for the preparation thereof
US6933046B1 (en) 2002-06-12 2005-08-23 Tda Research, Inc. Releasable corrosion inhibitor compositions
US6986943B1 (en) 2002-06-12 2006-01-17 Tda Research, Inc. Surface modified particles by multi-step addition and process for the preparation thereof
US7087544B2 (en) 2002-05-29 2006-08-08 The Regents Of The University Of California Nano-ceramics and method thereof
US7125939B2 (en) 2004-08-30 2006-10-24 Equistar Chemicals, Lp Olefin polymerization with polymer bound single-site catalysts
US7244498B2 (en) 2002-06-12 2007-07-17 Tda Research, Inc. Nanoparticles modified with multiple organic acids
WO2007118843A1 (fr) * 2006-04-18 2007-10-25 Basf Se Oxydes métalliques obtenus à partir de matériaux structurants organo-métalliques
US7303784B2 (en) * 2001-09-06 2007-12-04 Itn Nanovation Ag Method for producing self-cleaning ceramic layers and a composition therefore
EP1880041A1 (fr) * 2005-04-26 2008-01-23 TDA Research Compositions liberables empechant la corrosion
US10308541B2 (en) 2014-11-13 2019-06-04 Gerresheimer Glas Gmbh Glass forming machine particle filter, a plunger unit, a blow head, a blow head support and a glass forming machine adapted to or comprising said filter
WO2023166317A1 (fr) * 2022-03-04 2023-09-07 Evove Ltd Membrane

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CN107174975B (zh) * 2017-06-18 2020-06-09 玛雅森林(北京)国际科技有限公司 一种产富氢直饮水的海水淡化复合膜及其制备方法

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Cited By (23)

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EP1200498A4 (fr) * 1998-08-13 2002-09-25 Univ Wm Marsh Rice Procede et materiaux pour la production de polymeres d'alumoxane
EP1200498A1 (fr) * 1998-08-13 2002-05-02 Wm. MARSH RICE UNIVERSITY Procede et materiaux pour la production de polymeres d'alumoxane
US6953603B2 (en) 2001-04-21 2005-10-11 Itn Nanovation Gmbh Functional ceramic layers based on a support layer produced with crystalline nanoparticles
WO2002086194A2 (fr) * 2001-04-21 2002-10-31 Itn-Nanovation Gmbh Couches ceramiques fonctionnelles comprenant une couche support produite au moyen de nanoparticules cristallines
WO2002086194A3 (fr) * 2001-04-21 2003-05-30 Itn Nanovation Gmbh Couches ceramiques fonctionnelles comprenant une couche support produite au moyen de nanoparticules cristallines
US7303784B2 (en) * 2001-09-06 2007-12-04 Itn Nanovation Ag Method for producing self-cleaning ceramic layers and a composition therefore
WO2003099979A1 (fr) * 2002-05-24 2003-12-04 The Procter & Gamble Company Composition, necessaire et procede de nettoyage et/ou de traitement de surfaces
US7081441B2 (en) 2002-05-24 2006-07-25 The Procter & Gamble Co. Composition for cleaning and/or treating surfaces
US7087544B2 (en) 2002-05-29 2006-08-08 The Regents Of The University Of California Nano-ceramics and method thereof
US7244498B2 (en) 2002-06-12 2007-07-17 Tda Research, Inc. Nanoparticles modified with multiple organic acids
US6933046B1 (en) 2002-06-12 2005-08-23 Tda Research, Inc. Releasable corrosion inhibitor compositions
US6887517B1 (en) 2002-06-12 2005-05-03 Tda Research Surface modified particles by multi-step Michael-type addition and process for the preparation thereof
US6986943B1 (en) 2002-06-12 2006-01-17 Tda Research, Inc. Surface modified particles by multi-step addition and process for the preparation thereof
US6710005B1 (en) * 2003-04-10 2004-03-23 Equistar Chemicals, Lp Aluminoxane modification
US7084221B2 (en) * 2003-04-10 2006-08-01 Equistar Chemicals, Lp Polymerization catalyst system containing polyether-modified aluminoxane
US6841506B2 (en) * 2003-04-10 2005-01-11 Equistar Chemicals, Lp Polymerization catalyst system containing polyether-modified aluminoxane
US7125939B2 (en) 2004-08-30 2006-10-24 Equistar Chemicals, Lp Olefin polymerization with polymer bound single-site catalysts
EP1880041A4 (fr) * 2005-04-26 2010-06-09 Tda Research Inc Compositions liberables empechant la corrosion
EP1880041A1 (fr) * 2005-04-26 2008-01-23 TDA Research Compositions liberables empechant la corrosion
WO2007118843A1 (fr) * 2006-04-18 2007-10-25 Basf Se Oxydes métalliques obtenus à partir de matériaux structurants organo-métalliques
US8501150B2 (en) 2006-04-18 2013-08-06 Basf Aktiengesellschaft Metal oxides from metal-organic framework materials
US10308541B2 (en) 2014-11-13 2019-06-04 Gerresheimer Glas Gmbh Glass forming machine particle filter, a plunger unit, a blow head, a blow head support and a glass forming machine adapted to or comprising said filter
WO2023166317A1 (fr) * 2022-03-04 2023-09-07 Evove Ltd Membrane

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