Showing papers by "Cabot Corporation published in 2001"

Electrocatalyst powders, methods for producing powders and devices fabricated from same

Abstract: Electrocatalyst powders and methods for producing electrocatalyst powders, such as carbon composite electrocatalyst powders. The powders have a well-controlled microstructure and morphology. The method includes forming the particles from an aerosol of precursors by heating the aerosol to a relatively low temperature, such as not greater than about 400° C.

Organically modified aerogels, processes for their preparation by surface modification of the aqueous gel, without prior solvent exchange, and subsequent drying, and their use

Abstract: The present invention relates to novel, organically modified aerogels, uses thereof, and a process for producing them in which a) a hydrogel is introduced as an initial charge, b) the hydrogel obtained in step a) is subjected to surface modification, and c) the surface-modified gel obtained in step b) is dried. The present invention additionally relates to novel, organically modified wet gels, to a process for producing them, and to their use.

Oxygen reduced niobium oxides

Abstract: Methods to at least partially reduce a niobium oxide are described wherein the process includes heat treating the niobium oxide in the presence of a getter material and in an atmosphere which permits the transfer of oxygen atoms from the niobium oxide to the getter material, and for a sufficient time and at a sufficient temperature to form an oxygen reduced niobium oxide. Niobium oxides and/or suboxides are also described as well as capacitors containing anodes made from the niobium oxides and suboxides. Anodes formed from niobium oxide powders using binders and/or lubricants are described as well as methods to form the anodes.

Electroluminescent phosphor powders, methods for making phosphor powders and devices incorporating same

Abstract: Electroluminescent phosphor powders and a method for making phosphor powders. The phosphor powders have a small particle size, narrow particle size distribution and are substantially spherical. The method of the invention advantageously permits the economic production of such powders. The invention also relates to improved devices, such as electroluminescent display devices, incorporating the phosphor powders.

Hollow cathode target and methods of making same

Abstract: Sputtering targets and methods of making sputtering targets are described. The method includes the steps of: providing a sputtering metal workpiece made of a valve metal; transverse cold-rolling the sputtering metal workpiece to obtain a rolled workpiece; and cold-working the rolled workpiece to obtain a shaped workpiece. The sputtering targets exhibits a substantially consistent grain structure and/or texture on at least the sidewalls.

Use of surface treated aerogels derived from various silica precursors in translucent insulation panels

Abstract: Many translucent industrial insulation applications require optimization of both the thermal and optical properties. Currently, the thermal performance witnessed in today's products often limits the amount of available area which can be designated for translucent panels. For example, translucent wall panels for passive lighting systems must provide both adequate light transmission as well as sufficient thermal insulation. In granular fill systems, these demands can sometimes work against each other since thermal performance will improve as the panel thickness is increased but light transmission will decrease accordingly. In contrast, the optical properties can be significantly enhanced by careful control of the particle size and size distribution. This in turn impacts the thermal resistance since spaces between the particles act as large pores that dominate the heat transfer. We have investigated aerogel materials derived from commercially viable silica sources. Results indicate that depending on the silica precursor, particle size distribution, and control over other processing conditions, the optical transparency can be varied from 25% to 80% in a 20 mm layer. Within these same constraints, we have found the thermal conductivity can be varied from 0.0140 to 0.0210 W/m K. This ability to tailor the optical and thermal characteristics, coupled with superior thermal properties of aerogel, may enable more widespread acceptance.

Method of making a multi-phase aggregate using a multi-stage process

Abstract: A method of making an aggregate having a carbon phase and a silicon-containing species phase is described and includes introducing a carbon black-yielding feedstock and a silicon-containing compound feedstock into different stages of a multi-stage reactor. The reactor operates at a sufficient temperature to decompose the silicon-containing compound and to form a carbon black phase from the carbon black-yielding feedstock. At least one of the feedstocks may include a diluent, such as an alcohol, water, and aqueous based solution, and mixtures thereof.

Elastomer composite blends and methods - II

Abstract: Elastomer composite blends are produced by novel wet/dry mixing methods and apparatus. In the wet mixing step or stage, fluid streams of particulate filler and elastomer latex are fed to the mixing zone of a coagulum reactor to form a mixture in semi-confined flow continuously from the mixing zone through a coagulum zone to a discharge end of the reactor. The particulate filler fluid is fed under high pressure to the mixing zone, such as to form a jet stream to entrain elastomer latex fluid sufficiently energetically to substantially completely coagulate the elastomer with the particulate filler prior to the discharge end. Highly efficient and effective elastomer coagulation is achieved without the need for a coagulation step involving exposure to acid or salt solution or the like. Novel elastomer composites are produced. Such novel elastomer composites may be cured or uncured, and combine material properties, such as choice of filler, elastomer, level of filler loading, and macro-dispersion, not previously achieved. The coagulum produced by such wet mixing step, with or without intermediate processing steps, is then mixed with additional elastomer in a dry mixing step or stage to form elastomer composite blends. The additional elastomer to the coagulum may be the same as or different from the elastomer(s) used in the wet mixing step.

Carbon foams and methods of making the same

Abstract: A method of making carbon foam is described which involves pyrolizing a mixture containing at least one pyrolizable substance and at least one unpyrolizable material and then removing the unpyrolizable material to obtain the carbon foam. Carbon foam made by this process is also described. Incorporating the carbon foam in a variety of end use applications including electrodes, thermal insulation material, polymers, and the like is also described.

Printing plates comprising modified pigment products

Abstract: The present invention discloses printing plates comprising a substrate and a radiation-absorptive layer, wherein the radiation-absorptive layer comprises at least one modified pigment product. The modified pigment product comprises a pigment having attached at least one organic group and at least one amphiphilic counterion. Methods of imaging printing plates are also disclosed.

Modified pigment products, dispersions thereof, and compositions comprising the same

Abstract: The present invention relates to modified pigment products comprising a pigment having attached at least one organic group represented by the formula —X-Sp-Alk, wherein X, which is directly attached to the pigment, represents an arylene, heteroarylene, or alkylene group, Sp represents a spacer group, and Alk represents an alkenyl or alkyl group containing 50-200 carbon atoms. The use of these modified pigment products in non-aqueous dispersion compositions and in several applications, including printing plates, electrophoretic displays, liquid crystal displays, and ink, coating, toner, and polymer compositions is also disclosed.

Dielectric compositions and methods to form the same

Abstract: The invention provides dielectric compositions and methods of forming the same. The dielectric compositions may be used to form dielectric layers in electronic devices such as multilayer ceramic capacitors (MLCCs) and, in particular, MLCCs which include base metal electrodes. The dielectric compositions include a barium titanate-based material and several dopants. The type and concentration of each dopant is selected to provide the dielectric composition with desirable electrical properties including a stable capacitance over a temperature range, a low dissipation factor, and a high capacitance. Preferably, MLCCs including dielectric layers formed with the composition satisfy X7R and/or X5R requirements.

Ink compositions comprising modified colored pigments and methods for preparing the same

Abstract: The present invention describes an ink composition comprising a liquid vehicle and a modified colored pigment. The modified colored pigment comprises the product of a colored pigment having at least one leaving group and a treating agent. The modified colored pigments are also disclosed, as are processes for producing them.

Factors affecting the adsorption of stabilisers on to carbon black (flow micro-calorimetry and FTIR studies) Part I Primary phenolic antioxidants

Abstract: The surface activity of different types of carbon black with phenolic antioxidants is examined using flow micro-calorimetry (FMC), X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared spectroscopy (FTIR). Significant differences in both the overall adsorption activity and the levels of probe adsorption are observed. Differences in behaviour between types of carbon black are evident and show that the specific surface area is not the most important factor affecting the adsorption activity, but also the chemical nature of its surface. Essentially, two factors were found to affect the behaviour of phenolic stabilisers: Phenolic hydroxyl and ester groups were found to form the strongest interactions with carbon black. Furthermore, steric hinderance of phenolic hydroxyls by alkyl groups is the main factor which influences adsorption activity. In order to characterise different carbon blacks, FTIR and XPS analysis have been used in an attempt to determine the nature of functional groups present on the surface of the carbon blacks. FTIR analysis also shows that some adsorbed antioxidants on the surface of the carbon black could be successfully detected. This provides valuable information regarding the adsorption mechanisms on to carbon black surfaces. Other techniques included thermogravimetric analysis (TGA), N2 BET adsorption studies and Karl Fisher analysis. The latter were performed in order to determine differences in the volatile and water contents, respectively, of the carbon black samples.

High purity niobium and products containing the same, and methods of making the same

Abstract: High purity niobium metals and alloys containing the same are described. The niobium metal preferably has a purity of at least 99.99% and more preferably at least 99.999%. In addition, niobium metal and alloys thereof are described, which either have a grain size of about 150 microns or less, or a texture in which a (100) intensity within any 5% increment of thickness is less than about 30 random, or an incremental log ratio of (111):(100) intensity of greater than about −4.0, or any combination of these properties. Also described are articles and components made from the niobium metal which include, but are not limited to, sputtering targets, capacitor cans, resistive film layers, wire, and the like. Also disclosed is a process for making the high purity niobium metal which includes the step of reacting a salt-containing niobium and a metal salt along with at least one compound capable of reducing the salt-containing niobium to niobium and in a reaction container. The reaction container or liner in the reaction container and the agitator or liner on the agitator are made from a metal material having the same or higher vapor pressure of melted niobium. The high purity niobium product preferably has a fine and uniform microstructure.

Factors affecting the adsorption of stabilisers on to carbon black (flow micro-calorimetry studies): Part II : Hindered amine light stabilisers (HALS)

Abstract: The interaction of hindered piperidine light stabilisers (HALS) with carbon black has been examined using flow micro-calorimetry (FMC) and Fourier transform infrared spectroscopy (FTIR). Significant differences in both the overall adsorption activity and molar heats of probe adsorption are observed. Differences in adsorption behaviour between different types of carbon black were clearly evident and, as with a previous paper (see reference 1, in the latter paper, surface chemistry of the carbon blacks investigated is extensively analysed by XPS, FTIR, N2 BET adsorption and Karl–Fischer analysis), were mainly to be due to differences in carbon black surface chemistry. The specific surface area merely physically affected the level and heat of adsorption (per unit mass of carbon black). Variation in the degree of substitution of the piperidine amine is an important factor that is found to influence the adsorption activity of HALS, as well as the number of adsorption active and sterically accessible functional groups per HALS molecule. In some cases the adsorbed HALS could be detected by FTIR; shifts in absorption frequencies associated with both the adsorbate and the substrate yielded significant insight into the mode of adsorption of several of the HALS investigated.

Fine powders for use in primary and secondary batteries

Abstract: Fine battery powders and methods for producing fine battery powders. The powders have a well-controlled microstructure and morphology and preferably have a small average particle size. The method includes forming the particles from an aerosol of powder precursors. The invention also includes batteries formed from the powders.

Method of producing secure images using inks comprising modified pigment particles

Abstract: The present invention describes a method of producing an image which is visually distinct from its reproductions. This method comprises the steps of formulating an ink composition comprising a liquid vehicle and at least one modified pigment having attached at least one organic group and applying this ink composition to a substrate. Methods of determining the authenticity of an image and of verifying the date of creation of an image is also described.

A method for quantifying the texture homogeneity of a polycrystalline material

Abstract: A method for quantifying the texture homogeneity of a polycrystalline material is described. The method involves selecting a reference pole orientation; scanning in increments a cross-section of the polycrystalline material having a thickness with scanning orientation imaging microscopy or other measuring technique to obtain actual pole orientations of a multiplicity of grains throughout the cross-section of the polycrystalline material. The orientation differences between the reference pole orientation and actual pole orientations of a multiplicity of grains is then determined. A value of misorientation from the reference pole orientation at each grain measured throughout the thickness is then assigned. The average misorientation of each measured increment throughout the thickness is then determined. A texture gradient and/or texture banding can then be obtained by determining the first and/or second derivative, respectively, of the average misorientation of each measured increment through the thickness of the sample used for evaluation. A method to predict the sputtering efficiency of a target is also described as well as a system for quantifying the texture homogeneity of a polycrystalline material.

Coated barium titanate-based particles and process

Abstract: Coated barium titanate-based particles and a process to coat the particles are provided. The coating includes a dopant metal compound that is insoluble in water under alkaline conditions. The dopant metal in the coating is selected from the group of metals which form oxides or hydroxides that are soluble in water under alkaline conditions such as tungsten, molybdenum, vanadium, and chromium. The process involves precipitating the insoluble compound from an aqueous medium as a coating on surfaces of barium titanate-based particles. The coated barium titanate-based particles may be further processed, for example, to form dielectric materials which may be used in many electronic applications such as in MLCCs applications.

Factors affecting the adsorption of stabilisers on to carbon black (flow micro-calorimetry studies) Part III Surface activity study using acid/base model probes

Abstract: The first and second part of this series of papers investigated the interaction between carbon black and stabilisers (phenolic antioxidants and HALS, respectively) and showed that the mechanism was dependent on both the chemical nature of the carbon black surface and the molecular structure of stabilisers. In this third part, the interactions between model compounds, of varying acidity, and the same four carbon blacks, are investigated using flow micro-calorimetry (FMC) and Fourier transform Infrared spectroscopy (FTIR). As with the first and second parts, differences in adsorption behaviour between the four types of carbon black were evident and were principally related to the chemical nature of the surfaces and the adsorbates. In this study further insight in to the nature of the interactions between the carbon black surface functional groups and the acidic and basic probes has been acquired. The main forms of interaction are hydrogen bonding and Lewis and Bronsted acid/base interactions, formation of proton transfer complexes was also considered possible in cases of strong adsorption. The adsorption behaviour of acid and basic aromatic probes, together with octadecanol and stearic acid, was also found to be dependant on the carbon black surface topography. Flat graphene layers containing minimal heteroatoms favoured adsorption of the latter species as flat adsorption and/or structural ordering was permissable.

The use of vinyl functional aerogels for reinforcement of silicone rubbers

Abstract: Silane-treated silicate-based aerogels are excellent reinforcing fillers for silicone rubbers. The physical properties of the aerogel filler can be readily altered by controlling the properties of the hydrogel, and the vinyl functionality of the aerogel surface can be easily and precisely controlled in the silylation step of the aerogel manufacturing process. By changing the vinyl content on the surface of the aerogel, the physical properties of the rubber can be markedly changed without the use of any in situ treating agents during compounding or alteration in the formulation. The silicone rubber hardness and modulus of elasticity exhibit a sensitive response to the vinyl content, while the plasticity of the uncured base shows no effect of vinyl loading. In contrast, the viscosity (plasticity) of the uncured rubber is a strong function of the aerogel surface area, whereas the rubber modulus and strength are only slightly affected by particle properties such as surface area. In addition, the high porosity of aerogels allows for good fracture characteristics and dispersion of the filler during compounding, while the large pore size provides good accessibility to and utilization of the vinyl sites within the porous structure. The ability to easily control the aerogel structure, to completely hydrophobize the silica surface, and to precisely control the vinyl loading make aerogels a potentially useful new particle for rubber reinforcement. A brief summary of the treatment chemistry and the vinyl surface chemistry is also presented in the paper.

Method of preparing a fumed metal oxide dispersion

Abstract: The invention provides a method of preparing a dispersion of a fumed metal oxide in a liquid carrier comprising the following sequential steps: (a) providing a liquid carrier at a pH that effects dissolution of the metal oxide at a rate the same as or greater than the metal oxide dissolution rate in water at a pH of about 8, (b) mixing with the liquid carrier, in any order, one or more aliquots of both a fumed metal oxide and a metal ion source to form a dispersion, such that the dispersion does not coagulate, and (c) optionally adjusting the pH of the dispersion to the pH of the liquid carrier in step (a). The method allows for the preparation of the dispersion to be done with a high solids loading and at a high pH. Furthermore, the dispersion can have a shelf-life of at least about 1 hour or more at 25° C.

Electrophoretic displays containing modified particles

Abstract: An electrophoretic display containing modified particles is described. As well as non-emissive display systems. In the electrophoretic display, an arrangement of microscopic containers is used, wherein each container contains a dielectric fluid and a suspension of particles having attached at least one organic group, wherein the organic group includes at least one ionic group, ionizable group, or both, and wherein fluid and the particles contrast visually. The electrophoretic display also includes first and second electrodes wherein the arrangement is located between these electrodes and wherein one of the electrodes is substantially visually transparent. The electrophoretic display further includes means for creating a potential difference between the two electrodes so that the potential difference causes the particles to migrate toward one of the electrodes.

Surface-treatment chemistry in the manufacture of aerogels: computational modelling of cyclic and linear siloxanes

Abstract: An essential feature of some aerogel manufacturing processes is the `end-capping' of reactive silanol groups in the undried silica gel. Whilst the chemistry associated with the monofunctional trimethylsilanol-based processes is relatively straightforward, alternative chemistry involving multifunctional silylation reagents is not. An example of a multifunctional reagent is dimethyldichlorosilane, which rapidly hydrolyzes in aqueous environments, and in the hydrolyzed form, can condense with itself, yielding linear silanols. The resulting silanols may then further condense to form cyclic siloxanes. Such reactions will inevitably occur under typical end-capping conditions, so it is necessary to consider these when addressing the details of such treatments. We have used a variety of computational methods, including semi-empirical AM1 and PM3 as well as quantum mechanical HF/MP2 at the 6-31+G * and 6-311++G ** levels of theory, to investigate some of the siloxane species as isolated molecules. These calculations permit us to compare the enthalpies of formation of the various molecules. Furthermore, we are able to calculate various geometric attributes of the siloxanes. The calculations indicate that in the isolated state, the initial hydrolyses are nearly isoenthalpic, so other mechanisms are needed to explain the strong exothermicity observed in the laboratory. Chain extension of the linear diols is seen to be mildly exothermic with each step. Of the cyclic siloxanes, formation of the trimer, tetramer and pentamer are enthalpically most favored.