Showing papers by "Cabot Corporation published in 2012"

N–O Bond Homolysis of an Iron(II) TEMPO Complex Yields an Iron(III) Oxo Intermediate

Abstract: The reaction of TEMPO with the iron(I) synthon PhB(MesIm)3Fe(COE) leads to formation of the κ1-TEMPO complex PhB(MesIm)3Fe(TEMPO). Structural and spectroscopic data establish the complex contains divalent iron bound to a nitroxido anion and is isoelectronic to an iron(II) peroxo complex. Thermolysis of the complex results in N–O bond homolysis, leading to the formation of an iron(III) oxo intermediate. The oxo intermediate is active in oxygen atom transfer reactions and can be trapped by the triphenylmethyl radical to give the iron(II) alkoxo complex PhB(MesIm)3Fe(OCPh3).

Does carbon black disaggregate in lung fluid? A critical assessment.

Abstract: Carbon black is an industrially produced particulate form of nearly pure elemental carbon. The basic building blocks of carbon black are (1) primary particles, minute pieces of matter with defined physical boundaries; (2) aggregates, collections of strongly bound or fused particles; and (3) agglomerates, collections of weakly bound aggregates. Industrial carbon black is produced within a closed reactor where the primary particles form aggregates, which become the indivisible entities of carbon black. These aggregates then form agglomerates, which are the typical form of carbon black in commerce. Carbon black is often used in in vitro and in vivo particle toxicology investigations as a reference nanoparticle. The toxicology studies often report the sizes of the primary particles but rarely the sizes of the aggregates or agglomerates. It appears in many cases that there is a limited understanding of the fact that carbon black typically does not exist as primary particles but instead exists as aggregates and agglomerates. Moreover, many toxicology studies manipulate carbon black particles in order to disperse them so that the form of carbon black used in these toxicology studies may be substantially different from the form that may be encountered in the workplace environment. Since the main exposure route for carbon black is inhalation, the question arose as to whether inhaled carbon black may deagglomerate or disaggregate to either smaller aggregates or primary particles when in contact with lung fluids. This question relates to the concern that there may be additional hazards of smaller particles, such as their ability to translocate to tissues and organs beyond the lung and the ability to pass through the blood-brain barrier. The purpose of this assessment is to review the existing literature for evidence as to whether carbon black deagglomerates or disaggregates into smaller aggregates or primary particles when in contact with lung fluid. On the basis of a review of the physical characteristics of commercial carbon black and various toxicology studies, it appears that commercially produced carbon black in contact with lung fluid is unlikely to deagglomerate or disaggregate into smaller aggregates or primary particles.

Carbon blacks and use in electrodes for lead acid batteries

Abstract: A carbon black having a combination of properties with values in ranges selected to promote high conductivity, high hydrophobicity, and reduced outgassing in lead acid batteries while maintaining high charge acceptance and cycleability. The carbon black has a Brunauer-Emmett-Teller (BET) surface area ranging from 100 m2/g to 1100 m2/g combined with one or more properties, e.g., a surface energy (SE) of 10 mJ/m2 or less, and/or a Raman microcrystalline planar size (La) of at least 22 A, e.g., ranging from 22 A to 50 A. In some cases, the carbon black has a statistical thickness surface area (STSA) of at least 100 m2/g, e.g., ranging from 100 m2/g to 600 m2/g.

Toner additives comprising composite particles

Abstract: PROBLEM TO BE SOLVED: To provide particles that hardly drop off as external additives used to improve various properties of a toner.SOLUTION: In a toner composition, metal-oxide composite particles used as a toner additive are metal oxide-polymer composite particles comprising a metal oxide and a polymer. The metal oxide-polymer composite particles are distributed on the surface of toner particles. The metal oxide particles are covalently attached to the polymer. The surface of the metal oxide is modified with a first hydrophobizing agent. The moisture content of the metal oxide-polymer composite particles is from 0 wt.% to about 10 wt.% when measured after equilibration at 50% relative humidity and 25°C at about 1 atm pressure. The density of the metal oxide-polymer composite particles when measured by helium pycnometry is from about 30% to about 90% of the density of the metal oxide.

A case study combining incident investigation approaches to identify system-related root causes.

Abstract: This case study demonstrates an effective incident investigation approach to identify system-related root causes. The premise is simple: What people do makes sense to them at the time. The approach combines human error concepts and human factors analyses. The combined approach helps define and eliminate hindsight bias (the investigator's bias that exists because of the known bad consequence). The case study's human error mistake was simple and straightforward; however, it failed to capture the role that previous decisions played in the incident. The team's original recommendation was to be more careful next time. However, a deeper process safety management system-related issue was uncovered by continuing the probe using the human error root cause as the starting point of the investigation. This is the point where the real systemic issues are found. This case study showed how poor communications between the different people involved with engineering design, contractor fabrication, equipment inspection, and subsequent site installation caused the incident. The final recommendation of the team was to link the separate management of change (MOC), prestartup safety review (PSSR), and mechanical integrity quality assurance-related efforts together, ensuring an inspection step for replacement-in-kind. In conclusion, the combined approach helps the team better understand the timing and conditions of the event, better understand why people make the decisions they make at the time the event unfolds, and ensures that systemic root causes are discovered so that more appropriate, system-related preventive measures are chosen and implemented.

Metal nanoparticle compositions for reflective features

Abstract: A composition for the fabrication of reflective features using a direct-write tool is disclosed. The composition comprises metal nanoparticles having an average particle size less than 300 nm and which carry thereon a polymer for substantially preventing agglomeration of the nanoparticles, wherein the nanoparticles exhibit a metal-polymer weight ratio of 100:1 to 10:1. The composition further includes a vehicle for forming a dispersion with the metal nanoparticles. A number of electronic devices comprising a reflective layer formed from the composition are also disclosed. One example case provides an electronic device having a reflective electrode. The reflective electrode comprises a percolation network of the metal nanoparticles embedded in a matrix of the polymer and having an average particle size of less than 300 nm, wherein the reflective electrode is reflective in the visible light range and does not diffract incident light.

Patents and Industrial Applications of Aryl Diazonium Salts and Other Coupling Agents

Abstract: 1 Cabot Corporation Business and Technology Center, 157 Concord Road, P.O. Box 7001 Billerica, MA 01821, USA 2 Advanced Material Technology Consulting, 9 Avenue Paul Verlaine, 38030 Grenoble Cedex 2, France 3 University Paris Diderot, Sorbonne Paris Cite, ITODYS, UMR CNRS 7086, 15 rue J-A de Baif, 75013 Paris (France) 4. Laboratoire Sciences Analytiques Bioanalytiques et Miniaturisation, ESPCI, 10 rue Vauquelin, 75005 Paris (France)

Oil emulsification and polycyclic aromatic hydrocarbon adsorption using fine particles as dispersants

Abstract: A method for cleaning an oil spill in a marine environment includes forming a particle-stabilized emulsion containing seawater, carbon black and at least one oil spill component and allowing the at least one oil spill component to degrade, thereby removing said component from the marine environment. Carbon black can be added to an oil-seawater mixture to form a stabilized emulsion containing at least one oil spill component and the oil spill component allowed to degrade, thereby removing the at least one oil spill component from the oil spill. Also disclosed is an emulsion that includes one or more oil spill components, seawater and carbon black particles.

Elastomeric composites containing modified fillers and functionalized elastomers

Abstract: Elastomeric compositions are described which have at least one functionalized elastomer and at least one modified filler which has adsorbed and/or attached chemical groups, such as a triazole and/or pyrazole thereon, orother modified fillers which are also described. Methods are further described to improve hysteresis and/or abrasion resistance in elastomeric compositions containing a functionalized elastomer using the modified fillers of the present invention.

High resistivity coating compositions having unique percolation behavior, and electrostatic image developing systems and components thereof incorporating same

Abstract: Disclosed herein are resistive composites comprising at least one resin; at least one carbon black having a surface hydrophobically modified with at least one organic group, the at least one organic group having a molecular weight of 4000 or less and comprising the formula --X(G)—, wherein X is directly attached to the at least one carbon black and is selected from arylene, heteroarylene, and alkylene, G is a substituent of X, and —X(G)— is nonionic; and wherein the resistive composite has a volume resistivity, Rv, at a relative volume fraction, XCB, of the at least one carbon black in the coating, where Rv is at least 106 ohm-cm; and log Rv has a substantially linear relationship with XCB when XCB is varied from 0.1 to 0.5. Also disclosed are coatings made from such composites, such as coatings for rollers/belts for office automation machines, and methods of making such coatings.

Inappropriate exposure data and misleading calculations invalidate the estimates of health risk for airborne titanium dioxide and carbon black nanoparticle exposures in the workplace.

Abstract: Dear Editor: Ling et al. (2011) have attempted to assess the potential health risk from exposure to airborne TiO2 nanoparticles (TiO2 NPs) and carbon black nanoparticles (CB NPs) in the workplace. Unfortunately, the data used by the authors are totally inappropriate for this purpose. First, the TiO2 data were generated by an artificial laboratory experiment producing TiO2 particles of 30–60 nm diameter (Chen et al. 2007) — these particle sizes are very atypical for the workplaces with TiO2 exposure (Berges et al. 2007; Wake et al. 2002). Second, the numbers that Ling and co-workers extracted from Kuhlbusch et al. (2004) did not describe CB NPs. Kuhlbusch et al. (2004) and Kuhlbusch and Fissan (2006) clearly reported that the observed NPs in the CB workplaces were not carbon black particles but due to other sources such as forklift and gas heater emissions (see also Wake et al. 2002). Furthermore, the exposure model used by Ling et al. (2011) assumes that workers are exposed to these particle concentrations for 8 h a day, 240 days a year and for 30 years. Since the particle concentrations observed in the study by Kuhlbusch et al. (2004) do not even relate to CB NPs, these exposure assumptions vastly overestimate any actual exposures to CB production workers. In consequence, the conclusions drawn by Ling et al. (2011) are unsupported. The severe problems with the inappropriate exposure data are compounded by the dose–response modelling conducted by Ling et al. (2011). For CB NPs, the inflammationrelated effects are based on a short-term inhalation study in rats. There are some data (ILSI Risk Science Institute Workshop 2000; Hesterberg et al. 2005, 2006) indicating that a dose–response assessment based on rat data may overestimate effects in humans because rats appear to be more sensitive to the respiratory effects of poorly soluble particles, such as carbon black, compared to other species. For TiO2 NPs, the inflammation-related effects are based on an acute intra-tracheal instillation study in mice. For both CB NPs and TiO2 NPs, the cytotoxicity-related effects are based on in vitro cellular assays where the cells are dosed for 1–3 days. There are so many uncertainties involved in extrapolating data from acute studies with non-physiological routes of administration to determine long-term adverse effects in humans that the results can be very inaccurate (US-EPA 2002). To account for such uncertainties, Ling et al. (2011) include uncertainty factors ranging from 100 to 10,000 for each endpoint. Therefore, humans are considered to be 100–10,000 times more sensitive than the animal species or cellular assays used in this evaluation. While the use of these uncertainty factors is health-protective, it is important to Responsible editor: Vera Slaveykova

Methods and apparatus for the detection of taggants by surface enhanced raman scattering

Abstract: One embodiment is a SERS enhancing substrate which includes a porous substrate and a Raman enhancing material associated with a surface of the porous substrate. The Raman enhancing material may be a Raman enhancing metal or other Raman enhancing material. The Raman enhancing material may also be configured to improve binding of a taggant to the substrate. The substrate described above may be included in a sample vessel useful for the flow-through analysis of large sample volumes, or for the rapid analysis of very dilute samples. Other embodiments include methods and systems for detecting taggants with SERS and similar techniques.

A surgical risk reduction approach to reduce global process safety risk: The “PSM gamma-knife”

Abstract: Businesses with more than one site strive to minimize operational variability across their entire organization. However, uniformly implementing company-wide standards is difficult because each site maintains its own personality—its own culture. When a business strives to reduce its global process safety risk, a significant incident that exposes a particular site's weakness may result in a simple corporate decision forcing all sites to implement the same process safety improvement. This article shares the basic concept and the novel use of a risk minimization tool, commonly used to reduce financial risks in an investment portfolio, to help decision-makers minimize their multisite, global process safety risk without adding undue stress on the rest of the organization. This approach helps quantify each individual site's process safety risks into a global business process safety risk model, uses a Monte Carlo simulation to determine which site-specific factors contribute the most to the overall business risk, and then helps decision-makers prioritize and choose site-specific risk reduction efforts that minimizes the global risk. The global process safety risk reduction model used to show how to use this approach is based on a simplified risk equation containing site-specific terms for frequency, consequence and operational discipline. Often the most contentious term in risk estimating is the frequency, especially with significant scenarios that have never happened before and, hence, have a very low likelihood. The beauty of the Monte Carlo simulation is that the user can account for the uncertainty in the frequency by choosing a frequency probability function based on a range of possible best- to worst-case consequence scenarios. From the surgical perspective, a person (the whole organization) with cancer is often adversely affected when treated with chemotherapy. The results from this approach, using the image of a “PSM Gamma Knife,” show how selective site-specific risk reduction treatments specifically address each site's process safety risk to help reduce the overall risk without adversely affecting the health of the whole organization. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012

Forming photovoltaic conductive features from multiple inks

Abstract: Photovoltaic conductive features and processes for forming photovoltaic conductive features are described. The process comprises (a) providing a substrate comprising a passivation layer disposed on a silicon layer; (b) depositing a surface modifying material onto at least a portion of the passivation layer; (c) depositing a composition comprising at least one of metallic nanoparticles comprising a metal or a metal precursor to the metal onto at least a portion of the substrate; and (d) heating the composition such that it forms at least a portion of a photovoltaic conductive feature in electrical contact with the silicon layer, wherein at least one of the composition or the surface modifying material etches a region of the passivation layer. When the surface modifying material is a UV-curable material, the process comprises the additional step of curing the UV-curable material.