External Additives Research Articles

Peanut-shaped nanoribbon bundle superstructures of malachite and copper oxide

A method for the preparation of peanut-shaped nanoribbon bundle superstructures of malachite (Cu 2(OH) 2CO 3) has been developed. The preparation involved thermal decomposition of urea and homogenous precipitation of copper acetate in the absence of any external inorganic additives or structure-directing organic templates. Copper oxide with similar morphology could be easily formed by a simple thermal treatment of the peanut-shaped malachite bundles in air. This study provides a new strategy for the preparation of inorganic materials with bioinspired morphology.

Polyaniline–Silica Composite Conductive Capsules and Hollow Spheres

AbstractIn this paper, we report on the preparation of monodisperse polyaniline (PANi)–silica composite capsules and hollow spheres on monodisperse core–gel‐shell template particles. An extension of the previously reported inward growth method was used. The samples were self‐stabilized without external additives. The core–gel‐shell particles were prepared by the inward sulfonation of monodisperse polystyrene particles. The introduced sulfonic acid and sulfone groups are responsible for the gel properties. The gel‐shell thickness and core size were synchronously controlled over the whole particle radius range. After aniline (ANi) monomer was preferentially absorbed in the sulfonated polystyrene shell, PANi was formed by polymerization. PANi was doped in situ with a sulfonic acid group to give the capsules a high conductivity. PANi hollow spheres were derived after the polystyrene cores were dissolved: their cavity size and shell thickness were synchronously controlled by using different core–gel‐shell particles. The PANi–silica composite capsules and hollow spheres were therefore prepared by a sol–gel process using tetraethylorthosilicate in the conducting shell. The PANi shell became more robust while maintaining the same conductivity level. Morphological results indicate that the PANi and silica formed a bicontinuous network. Fourier‐transform infrared (FTIR) spectra revealed that the hydrogen bonding in the PANi–gel shell was enhanced after the silica phase was incorporated, which could explain the high conductivity level after the silica phase was added. In a converse procedure, silica capsules and hollow spheres were prepared by a sol–gel process that incorporated tetraethylorthosilicate into the core–gel‐shell templates, which was followed by the absorption and polymerization of aniline in the silica shell thus forming PANi–silica composite capsules and hollow spheres. The silica capsules and hollow spheres thereby became conductive.

Novel Photoactive Self-Assembled Monolayer for Immobilization and Cleavage of DNA

This contribution reports on a novel self-assembled monolayer (SAM) on a gold surface, able to immobilize double-strand DNA and to induce its cleavage upon light excitation. DNA binding with the SAM is mainly driven by a highly favored electrostatic interaction, and it is shown that DNA immobilization takes place without impairing its intrinsic high order. SAM irradiation leads to an uncommon defluorination reaction, and it is unambiguously demonstrated that DNA breakage is strictly interrelated to this photochemical pathway. The photocleavage process is very efficient, is exclusively controlled by illumination conditions, seems to be non-base-specific, and does not require external additives. These features, together with the low excitation energy required, the prolonged thermal stability under physiological conditions, and the ease of preparation, make the SAM presented herein an appealing model system for designing nanodevices for applications where efficient, non-base-specific, and externally tunable cleavage of nanoscaled DNA arrays is required.

The Effect of Toner Blend Conditions on Charge Admix Performance

Even for a fixed composition, the charging performance of a toner may show discernable differences between different production batches, and this can be a practical problem for commercial toners that are produced in multiple, worldwide production facilities. This effect may be especially evident in toners based on external additives — variations in the level and distribution of external additives can be a major source of variability in toner performance, since external additives enhance the basic properties of the base toner. As a result, the additive-blending production process can be a significant source of toner performance variability. Furthermore, toner particles experience additional mixing forces during the final packaging operation, during the developer production process (i.e., during the production mixing of toner and carrier particles to create a final developer at a specified toner concentration), and during actual operation in a xerographic development module, and these secondary mixing events can also create changes in toner performance.While external toner additives can affect several key toner properties such as flow, cohesivity, humidity sensitivity, cleanability, etc., the effect of minor variations in blend conditions on performance is often most evident from a toner's charge admix response. This latter property is a measure of the rate at which uncharged, dispensed toner equilibrates with charged toner in a working developer). Since uncharged or poorly-charged toner particles will tend to develop in background, non-image areas, a rapid rate of charge admix is necessary for acceptable xerographic performance.In this present study, charge admix measurements on a single toner design were used to illustrate how changes in toner blend conditions can create a range of charge admix performance, from unacceptably slow to an excellent rapid rate. The major blender topics considered include modes of mixing, along with a range of blend conditions for a single blender.

Toner Characteristics and Xero Interactive Performance of EA Particles with Specific External Additives

Small particle size of silica and titanium oxide as external additives for toner have been used to control toner flow and charging characteristics.Recently, in order to meet high priority requirements, such as better image quality and the highest possible reliability, color toner size is getting smaller, and is being covered with highly loaded additives. As the process speed increases, the developer including the toner and carrier, is required to exhibit corresponding developability, transfer, cleaning and fusing characteristics.It is very difficult to maintain high transfer and cleaning performance of spherical toner with small external additives.We developed EA (emulsion aggregation) color toner containing at least substantially spherical silica fine particles having a size of 100nm to 150nm and a narrow size distribution. This EA toner exhibits satisfactory fluidity, high transfer efficiency and cleanability while retaining environmental stability and durability. The developer does not cause any toner filming on the surface of a photoreceptor and or on the surface of a carrier.

Metal-assisted red light-induced efficient DNA cleavage by dipyridoquinoxaline-copper(II) complex.

Complete cleavage of double stranded pUC19 DNA by the complex [Cu(dpq)2(H2O)](ClO4)2 (dpq, dipyridoquinoxaline) has been observed on irradiation at 694 nm from a pulsed ruby laser, assisted by the metal d-band transition as well as the quinoxaline triplet states in the absence of any external additives.

Study of the Effect of External Additives on Toner Performance

External additives for toners such as hydrophobic fumed silica and hydrophobic titania have been widely used for improvement of toner performance. Toners formulated for use in laser printers and PPC (Plain Paper Copiers) are being developed, aimed at high speed copying, high image quality and downsizing. To meet the challenges of more demanding requirements, toners are designed utilizing both smaller and larger particle size external additives to achieve better flowability, higher durability, higher image density and stable electrostatic charge under ambient conditions. Usage levels are also increasing. In addition to improved overall toner flow and charge properties, this trend is associated with improving cleaning properties such as reduced fogging and adherence of toner to paper.As such properties can be influenced by external additives, it is important for the toner formulator to know which characteristics need improvement in the already design stage.This paper describes the design and the selection of external additives. It will address the influence of mixing time of external additives on the tribo-electrostatic charge (T-ESC), charge distribution, and flowability of toners. In addition, the influence of surface chemistry of external additive on the admix performance is discussed. Finally, experimental results of the performance of color toner mixed with several kinds of external additives are reported.

The Effect of Toner and Carrier Physical Properties on Developer Conductivity

The electrical conductivity of a two component conductive developer decreases with increasing toner concentration, since the insulative toner particles block carrier-to-carrier contacts. This effect is a function of toner and carrier physical properties such as size, density and the intrinsic conductivity of the carrier particles. However, this effect can be moderated through additional factors such as carrier surface roughness and lubricating toner external additives. In the present paper, these various effects will be illustrated, using an analysis of experimental conductivity data taken on three sizes of model toners.

Intramolecular and Intermolecular Reactivity of Localized Singlet Diradicals: The Exceedingly Long-Lived 2,2-Diethoxy-1,3-diphenylcyclopentane-1,3-diyl

The direct and benzophenone-sensitized photodenitrogenation of the diethoxy-substituted diazene 3 in nonprotic solvents, e.g. n-hexane, benzene, and acetonitrile, afforded exclusively the housane 4 through the intermediary 2,2-diethoxy-1,3-diphenylcyclopentane-1,3-diyl diradical 2b. Alternatively, in the presence of methanol, the formation of the adduct 6 competed through trapping of the allylic cation 5. The intervention of the intermediates was corroborated by laser-flash photolysis experiments of the diazene 3. The diradical intermediate was characterized by its strong transient absorption at 545 nm, which decayed with a first-order lifetime in the microsecond range. The diradical lifetimes increased in the order n-hexane (0.52 μs), benzene (0.88 μs), acetonitrile (1.01 μs), and chloroform (3.73 μs). The singlet ground state of the 2,2-diethoxy-substituted 1,3-diradical 2b is suggested by the absence of EPR signals at low temperature, the lack of quenching by molecular oxygen, and the calculated (UB3LYP/6-31G*) singlet preference of ca. 4 kcal mol-1 for 2,2-dihydroxy-1,3-diphenyl-1,3-cyclopentanediyl as a model. Trapping of the 1,3-diradical 2b by external additives, e.g., olefins, dienes, and TEMPO, was not observed. In protic solvents, a decrease of the diradical lifetimes with increasing acidity was noted, e.g., the lifetime in acetic acid dropped to 70 ns. Moreover, a concomitant growth of an additional transient at 470 nm was found in acidic solvents, which was assigned to the allylic cation 5. The factors governing the intramolecular and intermolecular chemical reactivity of the localized singlet diradical 2b are discussed.

Small particle adhesion: measurement and control

A number of technologies, including electrophotographic printing, require an understanding of particle–surface adhesion forces. At Xerox, we have developed and applied new techniques in order to understand the dependence of particle adhesion on physical properties, such as particle charge, shape and surface roughness. Atomic force microscopy and computer modeling were used to investigate the effects of surface roughness, external additives and applied electric fields on the adhesion of single particles. Centrifugal detachment was used to measure the adhesion force distribution of several hundred particles simultaneously and to determine its sensitivity to particle charge and size. Electric field detachment has enabled rapid characterizations of the adhesion of particle layers, providing insight into the roles of particle–surface contact area and nonuniform particle charging on the adhesion of ensembles of particles. The addition of digital photography to the detachment techniques has allowed in-situ visualization of particle detachment, enabling us to probe interparticle effects on adhesion.

The Effects of Carrier and External Additives on the Tribocharging Properties of Toner

The Effects of Carrier and External Additives on the Tribocharging Properties of Toner

Synthesis of SiC-AlN Powder and Characterization of Its HIP-Sintered Compacts.

SiC-AlN powder was synthesized from a powder mixture of Si, Al and C through direct reaction between the constituent elements, i.e., (1-x)Si+(1-x)C+xAl+(x/2)N2=(SiC)1-x(AlN)x. A green compact of the mixed elemental powders was fired in nitrogen, and a porous compact composed of SiC and AlN and their solid solutions was obtained. This porous compact could be easily pulverized to fine SiC-AlN powder by ball-milling. Ultrafine microstructure with fine grains smaller than 100nm was obtained by hot-isostatic pressing (HIP) of the synthesized powders without external additives. Most grains therein were SiC-AlN solid solutions with compositions close to the nominal mixed ratio. The obtained SiC-AlN ceramic alloys, here referred to as homogeneous solid solutions and their mixture, showed better mechanical properties than SiC and AlN. In particular, high strength, more than twice that of the conventional monolithic SiC, was obtained in the SiC-50 mol% AlN composition mainly because of its ultrafine-grained microstructure. This was also the main reason for the present SiC-AlN ceramic alloys to exhibit ductile deformation at relatively low temperatures.

Magnetic field effect on the benzophenone-sodium dodecyl sulphate system: influence of external additives

Addition of small amphiphiles such as 1,4-dioxane is found to affect radical recombination and escape rates in micelles such as sodium dodecyl sulphate (SDS). This has been demonstrated with the hydrogen-abstracted product of triplet benzophenone as the probe molecule. This result has been interpreted on the basis of the ability of dioxane to form “mixed” micelles, which thereby affect the size, viscosity and reflectivity of the boundary of SDS. Studies in presence of magnetic fields up to 15 kG show that the magnetic field effect remains unaffected by the addition of dioxane. This his been explained as due to the combined effect of size, viscosity and reflectivity of the boundary of the micelle.

Formulation and Compaction of Microspheres

AbstractThe factors affecting the tabletability of formulations containing uncoated and/or coated microspheres were discussed by presenting a case study. The size and shape, as well as surface properties of microspherical particles, the type and amount of coating agent, selection of the external additives, and the rate and magnitude of the pressure applied were found to be the most critical factors to be considered in order to obtain and maintain the desired drug release properties of the microspheres. It was found that microcrystalline cellulose was needed in order to produce satisfactory beads in terms of size, shape and surface characteristics. The microsphere formulations, which were found to be highly sensitive to lubrication, were more compressible than their powder forms, but produced much weaker tablets. When coated with Surelease, increasing the amount of coating on the pellets reduced the tensile strength of their compacts. Compaction of the microspheres at high velocities resulted in a decrease...

Compaction studies on pellets I. Uncoated pellets

Pellets made from microcyrstalline cellulosem plus dicalcium phosphate dihydrate, lactose and propanolol HCl were compacted on an Integrated Compaction Research System. Several methods including porosity changes, Heckel equation, total work of compaction and average power consumption were used to compare the compaction behavior of the pallets with that of the powers from which they were formed. The effect of external additives and punch velocity on the compaction properties of the pellets was also studied. Significant differences between the compaction properties of the pellets and the powders were observed. It was found that the powders examined compacted by plastic deformation and produced strong compacts, whereas, their pellets exhibited elastic deformation and brittle fragmentation which resulted in compacts of lower tensile strength.

Influence of external additives on the preservation of carthamin red colour: an introductory test for utilizing carthamin as a herbal colorant of processed foods

A number of carbohydrates and related compounds was admixed with carthamin in an acidic buffer solution and the effect of the test chemicals on carthamin stability examined at low temperature. Monosaccharides were scarcely effective, although slightly accentuated values were obvious in thed-forms (d-form∶l-form=1.3∶1.0). Disaccharides were less effective for carthamin red preservation (dimer∶monomer=1.0∶1.8). However, a high level of colour conservation was observed with sugar alcohols. Both polyethylene glycol and glycerine very effectively protected carthamin from bleaching in solution: the colour preservation rates calculated were 91.3% and 83.8%, respectively, after 24 h incubation at 5° C in the dark. Gelatine was also effective for maintaining carthamin colour (preservation rate: 81.3%). The results are assessed in connection with utilizing carthamin as a herbal colorant of processed foods.

Thermal‐mechanical properties of PVC flame retarded alloys

AbstractSeveral segments of the plastics conversion industry are concerned with meeting critical functional and performance demands. Relevant concerns include flame spread, smoke generation, and toxicity. In recent decades, the transportation and electrical/electronics industries have consumed tremendous quantities of polymeric materials. Many of these plastics have been extensively modified to meet flammability criteria, processability demands, and other functional requirements. Aircraft and electronics applications of these materials include printed circuit boards, electrical connectors, wiring, wire harnesses, and aircraft cabin flooring, ceiling, paneling, carpeting, and cargo storage bins. The traditional mechanism for imparting flame retarding properties is to incorporate external additives, which alter burning characteristics, but at the expense of functional properties. An alternate solution to flame retarding that has gained much attention in recent years is the alloying, or blending, of flammable polymers with inherently flame retarded polymers. ASTM protocol has established dynamic mechanical testing (DMT) techniques to evaluate the rheological properties of such materials. This paper exhibits how DMT can be used to monitor the solid properties of various flame retarded alloys.

モモの葉抽出物の抗炎症作用及び入浴剤への応用

Although peach leaf is used in external preparations and bath additives for dermal diseases, its pharmacological effects are not sufficiently understood. In this study, we evaluated the anti-inflammatory effect of peach leaf extract on UV-induced erythema in guinea pigs, carrageenin-induced hind paw edema in rats, in vitro emigration of leukocytes, and PGE2 production in cell culture. In addition, the effects of bath additive containing peach leaf extract on erythema induced by UV-irradiation in a human sunburn model were evaluated.UV-induced erythema and carrageenin-induced edema were inhibited by immersion in bath containing peach leaf extract, and leukocyte emigration and PGE2 production were inhibited by extract preparation. UV-irrradiation induced erythema measured by the colorimeter was significantly more suppressed by bathing with additive preparation than by control (plain water) bathing.We conclude that peach leaf extaract has anti-inflammatory effect and that bath additive containing peach leaf extract may have benefitical effect on inflammatory dermal diseases such as dermatitis solaris.

Role of External Additives on the Surface Crystallization of Multi-Component Non-Alkali Glasses

The crystallization behavior of a glass in the SiO2-Al2O3-CaO-ZnO-TiO2-B2O3 system with additives was investigated by means of DTA, XRD and SEM observation. The additives were wollastonite, silica, lime, Fe2O3, alumina, zirconia, zircon, 36.6CaO⋅63.4SiO2 glass, titania, montmorillonite, kaolin, talc, zeolite. The main results are as follows. (1) The most effective additives that reduced the double peaks of DTA curve into a single one were wollastonite, TiO2 and 36.6CaO⋅63.4SiO2 glass. Among them, only external addition of wollastonite shifted the peak temperature downward. (2) Crystal precipitation was enhanced on the wollastonite contacted glass surface. (3) The precipitated crystalline phase was speculated to consist of tiny particles of anorthite, gehlenite, willemite and titanite crystals.

ChemInform Abstract: Sintering and Properties of β′‐Sialon with a Nitrogen‐Rich Y2O3 Sintering Aid.

AbstractThe synthesis of dense sintered β'‐sialon is achieved by using external additives selected from the Y2O3‐AlN‐SiO2 system.