bluuebunny/crossref_metadata_2025 huggingface dataset:
Laserautragschweißen und Laserlegieren — Gemeinsamkeiten und Unterschiede
Authors: Görgl R. , Brandstätter E.
Published: December 2013

Kurzfassung

Laserautragschweißen und Laserlegieren sind beides Technologien zur Oberlächenmodiikation von Werkzeugen und werden hauptsächlich zur lokalen Verbesserung des Widerstands gegen Verschleiß und/oder Korrosion eingesetzt. Während es sich beim Laserautragschweißen um eine mittlerweile weit verbreitete Technologie handelt, zu der es auch Konkurrenztechnologien gibt (z. B. PTA-Schweißen, Flammspritzen), ist das Laserlegieren eine einzigartige Technologie mit zurzeit nur einer realisierten industriellen Anwendung, jedoch hohem zuküntigen Potenzial. In diesem Artikel werden die Grundlagen, Unterschiede und Vorteile der beiden Technologien beschrieben sowie ausgewählte Anwendungen präsentiert. Ähnliche Technologien, welche nicht den Laser als Energiequelle verwenden, sind nicht Gegenstand dieses Artikels.
Hot friction and wear behaviour of plasma nitrided and low pressure carburized hot work tool steel sliding against 6082 Al alloy
Authors: Pellizzari M. , Siller I.
Published: December 2013

High temperature friction and wear behaviour of a hot work tool steel sliding against AA6082 alloy were investigated by means of a customary test configuration, which provides the conformal contact between a die block and an AA-disc. Uninterrupted tests in air were carried out. The friction behaviour is characterized by limited fluctuations just after the beginning of test, finally evidencing a transition to a more unstable contact regime after progressive transfer of Al to the die surface. The tendency towards Al pick up was evaluated by measuring the mass increase of die samples and their capability in delaying the formation of hard Al oxide particles, which are very detrimental for the surface finishing of the extrudate. The efficacy of different surface treatments, i.e. plasma nitriding and low pressure carburizing, was studied. Furthermore, samples with different level of roughness, corresponding to conventional machining (0.7–0.8 μm) and mirror polishing (0.02 μm), respectively, were produced. Finally the influence of hardness was also evaluated by considering two different hardness of the base steel (56 HRC and 44 HRC). In general, surface hardening improves the load bearing capability of the die surface, causing an extended permanence in the stable friction regime. Plasma nitrided samples (1125 HV 0.1) evidenced a better behavior than case hardened (670 HV 0.1) and base steel (56 HRC, 620 HV 0.1), respectively. Overtempered samples (44 HRC, 500 HV 0.1) confirm this trend. In view of the experimental error, a lower surface roughness did not improve the tribological properties.
Effect of the heating rate in the tempering of DIN 100 V1
Authors: Cajner F. , Landek D. , Rafel H. , Kovačić S.
Published: December 2013

In this paper, the effect of the heating rate on the process of tempering and the obtained hardness of the DIN 100 V1 (AISI W2) carbon tool steel has been investigated and determined. Steel specimens in two initial states were investigated: after quenching and after quenching and deep-cryogenic cooling. The specimens were submitted to tempering in a dilatometer, varying the heating rates, temperature of tempering between 200°C and 690°C and duration of keeping the specimens at that temperature. A common effect of these factors on the temperature of the start of particular stages in tempering and the obtained properties was determined using dilatometry. Differential dilatation analysis was carried out, together with hardness tests and XRD (X-ray diffraction) analysis.
Straightening of induction hardened shafts – influence on fatigue strength and residual stress
Authors: Fahlkrans J. , Melander A. , Gårdstam J. , Haglund S.
Published: December 2013

Straightening of distorted components after heat treatment is often a necessary operation. The straightening operation leads to local plastic deformation, which is affecting the residual stress state, the hardness, and ultimately the fatigue strength of the component. The present study evaluates the influence of a straightening operation on fatigue strength and on the residual stress state of induction hardened shafts of steel EN 42CrMo4. A simplified FEM model was formulated. The model showed that the residual stress state was asymmetric along the circumference of a straightened shaft. Fatigue testing was performed in a three point bending and showed that the fatigue strength was reduced by up to some 20 % by heavy straightening. A fracture mechanics model for fatigue crack growth and arrest was developed. The model could be used to predict the fatigue strength of a straightened shaft provided that the residual stress state was known.
Systematische Untersuchung verschiedener Einflussgrößen auf die Maß- und Formänderungen von einsatzgehärteten Stirnrädern
Authors: Steinbacher M. , Surm H. , Clausen B. , Lübben Th. , Hoffmann F.
Published: December 2013

Typically, highly stressed gears are heat treated to satisfy operational demands. Case hardening is a common heat treatment associated with power train components. In the heat treatment process complex distortion takes place, which has been studied in these examinations. Object of the actual investigations were spur wheels with small module. The case hardening was realized utilizing low pressure carburization with subsequent high pressure gas quenching in a heat treatment furnace of industrial proportion. The systematic analysis was guided using design of experiment methods. In strategic focus were the three contributing heat treatment steps heating, carburization and quenching. Heating related factors were the batch design and the preheating temperature. During carburization the temperature, carburization depth and surface carbon content were altered. Finally no quenching related variations were performed. The influences of the different parameters on the size and shape changes of the gear wheels were evaluated statistically. The identified main factors on size as well as on shape changes of the base body and the toothing will be presented and discussed.
Entwicklung eines Al-reduzierten Einsatzstahls für die Hochtemperatur-Aufkohlung∗
Authors: Konovalov S. , Prahl U. , Kohlmann R. , Bleck W.
Published: December 2013

Kurzfassung

Diese Arbeit zielt auf eine Verbesserung des oxidischen Reinheitsgrades in einem Einsatzstahl durch eine Reduktion des Aluminiumgehalts. Auf Basis des mikrolegierten Stahls 25MoCr4 wird ein neues Legierungskonzept vorgestellt, bei dem die Feinkornbeständigkeit auch für eine Hochtemperatur-Aufkohlung bei 1050 °C und höher mittels eines angepassten Niobgehalts sichergestellt werden kann. Das hier vorgestellte Legierungskonzept ist eine Weiterentwicklung von früheren Untersuchungen aus dem Jahr 2002, bei denen die Feinkornbeständigkeit gegenüber Hochtemperatur-Aufkohlung für eine aluminiumreduzierte Variante noch nicht ausreichend war. Das neue Konzept verwendet moderne thermodynamische Simulationsmethoden, um den korrekten Niobgehalt zur Substitution von Aluminium und Titan vorherzusagen. Die experimentelle Validierung des Konzepts erfolgte anhand einer Laborschmelze gegenüber einem Referenzwerkstoff und untersucht Reinheitsgrad und Feinkornbeständigkeit bei Hochtemperatur-Aufkohlung für industrienahe Prozessketten der Großgetriebeherstellung
In-situ sampling method (HSSE-TDS-GC-MS) during MVOC (microbial volatile organic compounds) measurements of metalworking fluids (MWF)
Authors: Weinhold M. X. , Siol A. , Koch T. , Grafe H. , Rabenstein A. , Thöming J.
Published: December 2013

Metalworking fluids (MWF) are used routinely throughout the world as cooling and lubricating agent for metal-cutting processes. They are important components to maintain the quality and precision of the metal-cutting but are slowly consumed within this process. Hence, monitoring of ageing of the MWFs before depletion is important for economical, ecological and security reasons. A method is presented, which enables to estimate the ageing of tools by measuring the microbial volatile outcome (MVOC) of the MWF. Measurements are done by headspace sorptive extraction combined to thermal desorption in a gas chromatography setup with mass selective detector (HSSE-TDS-GCMS). It could be shown that ageing of tools correlates to emission of ketonic and alcoholic MVOCs (namely 2-Heptanone, 2-Octanone, 1-Octanol, 2-Nonanone and 2-Decanone). Analysis of these components can be used as “ageing marker” for the investigated MWF solutions. The obtained information can further be used to calibrate electronic nose sensors for high-throughput and rapid analysis in future projects. Hence, it can be concluded that headspace analysis of volatile microbial metabolites by HSSE in combination with TDS-GC-MS is a suitable monitoring technique for the ageing of metalworking fluids.
Vergleichende Untersuchungen zur Bestimmung des Austenitgehalts austenitisch-ferritischen Gusseisens mit Kugelgraphit (ADI)
Authors: Morgenbrodt S. , Spieß L. , Teichert G. , Bamberger M. , Schaaf P.
Published: December 2013

Kurzfassung

Der Austenitgehalt bestimmt maßgeblich die mechanischen und chemischen Eigenschaften von Konstruktionselementen in Eisenwerkstoffen. So werden zum Beispiel die dynamische Festigkeit und das Korrosionsverhalten von Eisenlegierungen durch den Austenitgehalt beeinflusst. Die korrekte Quantifizierung dieses Gefügebestandteils in materialwissenschaftlichen Untersuchungen, in der Produktion und auch in der Qualitätskontrolle ist somit von großer Bedeutung. Aus der Vielzahl von Verfahren werden in dieser Arbeit das Wirbelstromverfahren, die magnetinduktive Methode, die Mössbauerspektroskopie, die Metallographie sowie die Röntgenbeugung zur Untersuchung von austenitisch-ferritischem Gusseisen mit Kugelgraphit (ADI) angewendet und miteinander verglichen. Die Messergebnisse der genannten Methoden zeigen zwar alle die gleiche Tendenz im Verlauf des Austenitgehalts auf, die gemessenen Absolutwerte variieren jedoch. Da Austenit und Martensit in Schliffbildern kaum voneinander zu separieren sind, eignet sich die Metallographie bei ADI-Proben nicht zur Quantifizierung.
Perspektiven der Heißzerspanung aus der Schmiedewärme
Authors: Egorov F. , Garbrecht M. , Brinksmeier E.
Published: December 2013

Kurzfassung

Die Heißzerspanung ist seit über 60 Jahren Forschungsthema und wird zum Teil für die Bearbeitung von schwer zerspanbaren Werkstoffen angewendet. Für den wirtschaftlichen Einsatz der Heißzerspanung sind die richtige Auswahl und die Energieeffizienz der Wärmequelle von großer Bedeutung. Als alternativer Lösungsansatz wird an der Stiftung Institut für Werkstofftechnik (IWT) in Bremen seit 2010, im Rahmen des Clusterprojektes EcoForge, die Heißzerspanung von ausscheidungshärtenden ferritisch-perlitischen Stählen unter Nutzung der vorhandenen Wärmeenergie aus dem Schmiedeprozess erforscht. Die Ziele sind dabei, das Potenzial der Heißzerspanung aufzuzeigen und durch die Integration der Zerspanung in die Wärmebehandlungsroute die Prozesskette deutlich zu verkürzen. In diesem Beitrag werden Ergebnisse von Werkzeugverschleißuntersuchungen beim Außenrund-Längsdrehen mit beschichteten Hartmetallwerkzeugen am Werkstoff 38MnVS6 in zwei Gefügevarianten, Ferrit-Perlit und unterer Bainit, bei 20 °C und 500 °C dargestellt und diskutiert.
Distortion of steel flat ring products during the production cycle∗
Authors: Česnik D. , Bratuš V. , Bizjak M.
Published: December 2013

The distortion of steel flat ring type products after fine-blanking and subsequent carbonitriding was investigated. All the analyzed products were produced from the same coil and under the same conditions of fine-blanking. The fine blanked products were afterwards heat treated by using three different procedures – carbonitriting, stress relief annealing and heat treatment in a neutral atmosphere under the same temperature regime as for carbonitriding. The contribution of fine-blanking, relief of residual stresses, uneven heating and cooling and the formation of carbonitrided cases on the overall distortion were determined. The results were complemented with hardness measurements, residual stresses measurements and observations of microstructure. The presented research work is the first step towards the understanding of the mechanisms and factors that influence the quality of the final products during the production cycle.
Trockenlauf-Gleitverschleiß von sintergehärteten Stählen∗
Authors: Klammer E. , Dlapka M. , Gierl-Mayer C. , Danninger H.
Published: December 2013

Kurzfassung

In Automobilgetrieben kommen heute zunehmend sintergehärtete PM-Präzisionsteile zum Einsatz. Um entsprechende Notlaufeigenschaften zu gewährleisten, muss auch ausreichende Verschleißbeständigkeit im Trockenlauf gegeben sein. In der vorliegenden Arbeit wurde das Verschleißverhalten von 4 unterschiedlich legierten Typen von sintergehärteten Stählen gegen Wälzlagerstahl 100Cr6 bei trockener Gleitbeanspruchung untersucht, wobei Gleitwege bis 200 km gefahren wurden. Es zeigte sich aus der Untersuchung des Abriebs, dass bei niedrigen bis mittleren Belastungen Tribooxidation als Mechanismus dominiert; die untersuchten Stähle unterscheiden sich hier nur geringfügig. Bei höheren Normalkräften tritt dagegen Delamination auf und etwas adhäsiver Verschleiß; hier erwiesen sich Cr-Mo-legierte Sinterstähle als deutlich besser als die in der Pulvermetallurgie bisher gängigen Ni-Cu-Mo-legierten Varianten.
Gasaufkohlen fast ohne Prozessgasverbrauch∗
Authors: Joritz D. , Edenhofer B.
Published: December 2013

Kurzfassung

Wärmebehandlungsöfen, insbesondere die zum Aufkohlen, Härten und Vergüten, arbeiten mit einem kontinuierlichen Prozessgasdurchfluss. Obwohl die verbrauchten Prozessgasmengen nicht unerheblich sind und einen gewissen Kostenfaktor der Wärmebehandlung darstellen, werden die Prozessgase von Wärmebehandlungsöfen bisher nur nutzlos abgefackelt. Eine neu entwickelte Technik nutzt die katalytische Wiederaufbereitung des Prozess-Abgases, bringt es in den ursprünglichen Zustand zurück und leitet es als frisches Prozessgas wieder in den Wärmebehandlungsofen zurück. Auf diese Weise lassen sich Prozessgasverbräuche von Aufkohlungs-, Härte- und Vergütungsöfen um bis zu 90 % verringern. Konzept, Ausführung und Funktionsweise dieser Aufbereitungstechnologie zusammen mit Ergebnissen der praktischen Nutzung sind Thema dieser Arbeit.
Austenitkornstabilität in pulvermetallurgischen Stählen bei hohen Sinter- und Wärmebehandlungstemperaturen∗
Authors: Dlapka M. , Gierl-Mayer C. , Strobl S. , Huemer M.-C. , Danninger H.
Published: December 2013

Kurzfassung

Bei der Wärmebehandlung von Stählen ist die Austenitkorngröße ein wesentlicher Parameter; zu hohe Austenitisiertemperaturen und/oder eine zu lange Dauer führen zu Kornvergröberung mit negativen Auswirkungen auf die mechanischen Eigenschaften. Bei sinterhärtenden Stählen ist Überhitzung aber unvermeidlich, da die Sinterung bei 1120–1280 °C durchgeführt wird. Mittels einer speziellen thermischen Ätzung wird hier gezeigt, dass Sinterstähle in einem breiten Dichte-/Porositätsbereich praktisch überhitzungsunempfindlich sind. Das Austenitkorn wird durch die Restporosität stabilisiert und sogar bei hochdichten Sinterstählen mit Restporosität < 4 % reichen die Poren aus, um das Kornwachstum beim Sintern zu unterdrücken.
The Ideal Quenching Medium? – Characterisation of Ionic Liquids for Heat Treatment of Metallic Components
Authors: Beck M. , Schmidt C. , Ahrenberg M. , Schick C. , Kragl U. , Keßler O.
Published: December 2013

Quenching as a part of heat treatment is an important process in the manufacturing chain of metallic components. One of the most common processes is immersion quenching in vaporising liquids. Unfortunately, this process is affected by the Leidenfrost-phenomenon. This effect can generate inhomogeneous quenching and thus asymmetrical residual stresses and avoidable distortion. In this work, ionic liquids have been investigated as new quenching media, which can be used as baths near room temperature. Aluminium cylinders have been quenched in baths of different ionic liquids with varying water contents and bath temperatures. The time-temperature curves have been recorded and the heat transfer coefficients were determined and compared to quenching in water. Addition of a few percents water to the ionic liquids increases the cooling rate significantly. Even at higher water contents, bubble boiling and convection are predominant and almost no Leidenfrost-effect occurs. This offers a huge potential to accelerate and homogenise immersion quenching.
Automatic Adsorptive Isolation and Biophysical and Biochemical Characterization of the Surface Film of Human Bronchoalveolar Lavage Fluid
Authors: Winsel Klaus , Lunkenheimer Klaus , Geggel Katrina , Witt Christian
Published: December 2013

Lung surfactant is the surface active material of the lung alveoli that makes breathing possible. It consists of various amphiphilic components like phospholipids and surfactant proteins and can be isolated by bronchoalveolar lavage from the lungs. The function of the surfactant system of the lungs is dominated by the composition of the surface film. It is therefore highly probable that alterations of the lung surfactant in lung diseases are mostly reflected in the surface film of bronchoalveolar lavage fluid. The aim of the study was to investigate the possibility of isolating the native surface film of bronchoalveolar lavage (BAL) fluid with the high-performance surfactant purification apparatus HPS 1 from the technical as well as from the theoretical point of view.

Basically this method represents a technique for the high-performance purification of ordinary surfactants to remove surface-active impurities and to achieve “surface-chemically” pure solutions. After adsorption from bulk BAL fluid (within 30 min) and subsequent compression of the adsorbed layer (by an surface area ratio of 1 to 30) the adsorbed layer was aspirated (one cycle) and the aspirated solution collected. This procedure was repeated for 100 and 200 times. The collected fractions of the aspirated solutions (after 100 and 200 cycles), the original BAL fluid pool and the residual bulk phase were analysed for the total protein, total phospholipids and phospholipid subclasses. In addition, the dynamic surface tension of the solutions was measured. Generally, there was an increase of the protein and the phospholipid concentrations in the aspirated fractions by a factor 2 to 3 in comparison to the corresponding concentrations of the BAL fluid. Analysis of the phospholipid subclasses shows that the aspirated solutions, i. e. the surface film, contains phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol. Phosphatidylethanolamine was not detected in the surface film. The percentage of phoshatidylglycerol in the surface film (100 cycles) was noticeably increased by 11.4% and 7.0%, respectively, in comparison to that of the BAL fluid. The equilibrium surface tension values of the aspirated solutions amounted to 37.5 and/or 40.3 mN/m (lavage fluid 1) and 38.6 and/or 40.2 mN/m (lavage fluid 2). The results prove that proteins and different phospholipids are integral parts of the surface film of BAL fluid and that this technique provides a new advantageous possibility for the isolation of native lung surfactant.
Cetyltriethylammonium Bromide for Large Pore Mesoporous Silicas MCM-41 Preparation
Authors: Liu Lei , Zhang Gao yong , Dong Jin xiang
Published: December 2013

Mesoporous silicas MCM-41 with larger and variable pore size were synthesized hydrothermally by using cetyltriethylammonium bromide (CTEAB) which has a larger hydrophilic head-group compared to cetyltrimethylammonium bromide (CTAB) as templating agent. Various factors such as surfactant and silica molar ratio, sodium hydroxide to silica molar ratio, the crystalization time, the amount of H2O on the pore structural properties of samples were investigated.

The experimental results showed that mesoporous silicas MCM-41 with a different pore diameter in the range of 4–7 nm can be obtained by adjusting surfactant and silica molar ratio. CTEAB is an effective templating agent for large pore diameter (>4 nm) of mesoporous silicas MCM-41. The MCM-41 pore structure properties did not change markedly when the amount of H2O increase in the range investigated in the paper.
Pseudo Ternary Diagrams of Pesticide Microemulsion Systems
Authors: Pratap A. P. , Bhowmick D. N.
Published: December 2013

In application of pesticide formulations, use of microemulsion systems offer several advantages over conventional systems such as wettable powders, emulsifiable concentrates (EC's), oil in water emulsions (O/W emulsions), water in oil emulsions (W/O emulsions) and aqueous suspension concentrates. Microemulsion systems are preferred for their long-term thermodynamic stability, low viscosity and ultimate economy. Microemulsion system also enables the usage of the least expensive solvent such as water. Formulation of agrochemical microemulsion is not a straightforward process. However, the pseudo ternary plot is a convenient mean of determining the compositions of microemulsion, macroemulsion and solubilized systems. Identification of specific regions in a pseudo ternary plot makes it possible to arrive at economical composition for microemulsion and solubilized systems. Such compositions gave maximum stability with the optimum usage of surfactants. These microemulsion and solubilized systems when diluted with the inexpensive solvent such as water gave macroemulsion and microemulsion respectively, which were stable over an extended period of time. This paper provides the basis for a simple procedure for the preparation of microemulsion systems employing water, oil, surfactant and cosurfactant.
Interactions of Hardness Ions with Polymeric Scale Inhibitors in Aqueous Systems
Authors: Amjad Z.
Published: December 2013

The interactions of hardness ions (i. e., Ca, Mg, Ba) with anionic polymeric scale inhibitors (SI) containing different functional groups has been investigated using a turbidity technique. It has been found that all SI tested form insoluble salts with hardness ions under the experimental conditions used (pH 7.0 to 10.0, 25 to 65 °C, 100 to 1,000 mg/L Ca). The results indicate that compatibility of hardness ions with SI decreases with increasing pH, temperature, and hardness ion concentrations and increases with increasing NaCl concentrations. It has also been found that compatibility of hardness ion with SI can be improved by incorporating bulkier and hydrophobic monomer into SI structure. In addition, the data suggest that SI architecture (i. e., molecular weight, monomer functional group, and nature of polymerization solvents) influences the interactions of hardness ions with SI in aqueous systems.
Analysis of Odorants Produced from Indoor Drying Laundries and Effects of Enzyme for Preventing Malodor Generation
Authors: Nagoh Y. , Tobe S. , Watanabe T. , Mukaiyama T.
Published: December 2013

Recently more consumers hang and dry their laundries indoor for various reasons. Under these slow drying conditions malodor was sometimes generated. Gas chromatography analysis showed the odorants were composed of medium-chain alcohols, medium-chain aldehydes, ketones, fatty acids, N-compounds and S-compounds. Especially, medium-chain fatty acids were confirmed to make up a characteristic and striking sweaty and sour odor. The malodor is supposed to be formed from sebum and soils by oxidative degradation as well as by metabolism of microorganisms. This study shows that a laundry detergent with an enzyme possessing high protease as well as bacteriolytic activity can prevent washed clothes from malodor generation during such a prolonged drying.
Monomer Exchange Kinetics, Dynamics of Concentration Fluctuations, and Chain Isomerization of Nonionic Surfactant/Water Systems. Evidence from Broadband Ultrasonic Spectra
Authors: Hanke Elke , Telgmann Thomas , Kaatze Udo
Published: December 2013

Ultrasonic absorption spectra, measured between 0.1 and 2000 MHz, are discussed for a variety of poly(ethylene glycol) monoalkyl ether/water (CiEj=H2O) mixtures. Depending on the temperature, the surfactant concentration, and on the length of the hydrophobic (Ci) as well as the hydrophilic part (Ej) of the surfactant molecules, the spectra reveal a multitude of shapes. The set of spectra, however, can be consistently described considering (i) a relaxation term representing the monomer exchange of the micellar solutions, (ii) another one that reflects the local fluctuations in the surfactant concentration, and, with several systems, (iii) additional terms due to CiEj associations or conformational isomerizations. The parameters of these terms are discussed in the light of relevant models. Evidence is presented for a more general view of a fluctuation controlled monomer exchange mechanism that combines aspects of both theoretical models, the micelle formation/decay kinetics and dynamics of local concentration fluctuations.
Synthesis and Investigation of Surfactants to the Purpose of Development of Fire Extinguishing Substances and Organisation of their Production in Ukraine*
Authors: Borovikov V. A. , Yurchenko I. A.
Published: December 2013

Foam concentrates for fire extinguishing have not been produced in Ukraine up to 1995, and need in them has been satisfied owing to their import. The purpose of the researches was development of biologically “soft” foam concentrates meeting today's requirements for the purpose of organization of their production in Ukraine. Analyses of raw materials sources and technological base of the country have been made as well as research of a number of surfactants, compounding of some foam concentrates have been developed and their production in Ukraine has been organized. Conditions of the most efficient application of a number of foam concentrates and ways for increasing of storage stability of their aqueous solutions in fire extinguishers and fire fighting installations have been found. A few normative documents and recommendations concerning testing and application of foam concentrates for fire extinguishing have been worked out.
Alkali Metal Cationization of Alkyl Glucosides under Electrospray Ionization Conditions
Authors: Zembrzuska Joanna , Zgoła-Grześkowiak Agnieszka , Frańska Magdalena
Published: December 2013

Alkyl glucosides have been studied by electrospray ionization mass spectrometry. The effect of the hydrophobic and the hydrophilic parts of these compounds on the stability of [M + Na]+ ions has been evaluated by mass spectra at growing cone voltages. The longer the hydrophobic or the hydrophilic part, the higher the stability of these ions. It has been also found that solvent used affects the abundances of [M + Na]+ ions. In order to check if the radii of alkali metal ions influence the stability of their adducts with the compounds studied, the mass spectra have been recorded for solution containing lithium and potassium ions. The cations of smaller radius form more stable adducts, especially with the compounds having longer hydrophobic parts.
Krafft Points and Cloud Points of Polyoxyethylated Nonionic Surfactants
Authors: Schott H.
Published: December 2013

The solubility of polyoxyethylated nonionic surfactants (POSs) in water is limited by an upper and a lower critical temperature. The former, called cloud point (CP), is the temperature at which POSs precipitate from solution on heating because of excessive dehydration of their polyoxyethylene (POE) moieties. The latter, called Krafft point (KP), is the temperature at which POSs crystallize from solution on cooling because of increased alignment and attraction between their hydrocarbon chains. It occurs less frequently: Even if the POSs were capable of crystallizing, ice often crystallizes first.

Aqueous solutions of over 100 POSs were examined by obtaining their CPs and ascertaining whether they exhibit KPs. KPs were found in polyoxyethylated primary alcohols and fatty acid amides and in polyethylene glycol esters of fatty acids. Only surfactants with strictly linear hydrocarbon chains crystallize, exhibiting KPs. Any branching, including that in polyoxyethylated linear secondary alcohols, prevents crystallization. Crystallization only occurs when the number mof carbon atoms in the hydrocarbon chains equals or exceeds 12. The KPs are then proportional to m. In homologous series, the surfactants most prone to crystallizing are those with borderline solubility, which possess just enough oxyethylene groups to promote solubility in cold water. Large POE moieties depress or eliminate KPs.
The Problem of Purity in Evaluating Surfactant Performance
Authors: Iyer Ramasubramania
Published: December 2013

Labeled surfactants have impurities in the form of un-reacted molecules or distributed products which is a constraint in evaluating its performance. This short review deals with the purity issue of surfactants and is divided into two parts. The first part deals with the methods of purification employed for obtaining a surface chemically pure surfactant for evaluation. In the second part the use of surface chemically impure surfactant in application areas of formulations is presented to highlight the impending impact on reproducibility of results.
Bleaching Product Development in View of Ecological Aspects
Authors: Cuypers L. , Hirschen M. , Reinhardt G.
Published: December 2013

The new European Detergents Regulation will enter into force 8 October 2005, dealing with the aerobic biodegradation of surfactants so far. An expansion of the regulation regarding all main organic detergent ingredients and anaerobic biodegradation aspects shall be reviewed until April 2009. Within the scope of this expansion also bleach activators will be affected, whereat in our opinion thought should been given to a specific characteristic of this ingredients category: whereas other detergent ingredients as surfactants, builders or solvents act in the washing process due to physical effects and therefore arrive at the environment in a chemical unchanged way, bleach activators react with per-oxo compounds during the washing process and hence change their chemical structure. So, regarding bleach activators, the environmental relevant compound differs from the compound being existent in the washing agent. This issue shall be pointed out considering various bleach activators as example.
Synthesis and Characterization of Mesoporous MCM-41 Templated by the Mixture of Cationic-Anionic Surfactant
Authors: Tai Xiumei , Wang Hongxia , Du Zhiping , Shi Xiuqi
Published: December 2013

Using the mixture of cationic cetyltrimethylammonium bromide (CTAB) and anionic Sodium Alkyl Epoxy Ethylene Carboxylate (AEC9Na) as template, tetraethyl orthosilicate (TEOS) as silica source, ethylenediamine (EDA) as base source, mesoporous MCM-41 has been synthesized at room temperature, characterized by X-ray power diffraction(XRD) and N2 adsorption. The results showed that with the change of the ratio of cationic to anionic surfactant the pore size can be controlled and the mesoporous MCM-41 has larger pore size than that synthesized by using CTAB alone as template.
Study on Production of High-monoester Sucrose Fatty Acid Esters by Improved Metallic Salt Method and Alcoholic Separation
Authors: Jinli Zhu , Shufen Zhang , Jinzong Yang , Pei Zhang
Published: December 2013

Crude sucrose fatty acid esters made by solvent-free process are purified by an improved metallic salt method and alcoholic separation. It is found that purified sucrose fatty acid esters can be obtained only by the use of calcium chloride in an amount stoichiometrically equivalent to the amount of the potassium stearate to be removed or in a slight excess amount. Among other soaps, potassium stearate is removed more easily from the crude sucrose fatty acid esters, which shows that potassium stearate is the most suitable soap for the solvent-free synthesis of sucrose fatty acid esters. In addition, it is also found that pure sucrose fatty acid esters can be quantitatively separated into two fractions, one with high-monoester content, and the other with low-monoester content. Sucrose fatty acid esters with a wide range of HLB can be obtained by mixing the two parts in varied proportions. An equilibrium relationship between the distribution of sucrose fatty acid esters with a high HLB in liquid phase and sucrose esters with a low HLB in the precipitate is studied and a triangle graph and equations are given. According to the triangular graph and the equations, the yield of the two fractions can be predicted.
The Quantitative Characterization of Chemical Modification of Sodium Dodecyl Sulphate Micellar Solutions and Retention Model in Micellar Liquid Chromatography
Authors: Samokhina L. , Loginova L. , Stepanko D.
Published: December 2013

The micelle solutions of sodium dodecyl sulphate (NaDS) modified by simultaneously presence of different aliphatic alcohols and an inorganic salt have been quantitatively characterized by the values of critical micelle concentrations, the degrees of counter-ion binding and electrostatic potentials of surface. The obtained characteristics of hybrid micelles and the coefficients of modifier distribution between aqueous solution and micellar pseudophase were used to develop a conceptual retention model in micellar liquid chromatography (MLC). The new retention model takes into account the microenvironment changes of an analyte when it goes from the hybrid micellar eluent to a modified surface of alkyl-bounded sorbent.
Testing Robustness and Compatibility of Colour Damaging Washing Tests
Authors: Reinhardt G. , Ulshöfer H.
Published: December 2013

A significant aspect when selecting new bleaching agents is their reactivity on dyed textiles. In this paper the colour damaging effect of various the bleach activators are compared with that of tetraacetyl ethylene diamine. The tests were carried out according to ISO 105-C09 (diagnostic single wash test) and a similar test as well as the recently developed colour damaging profile test (20 wash cycles) using the AISE Dye Set. The results confirm that new bleach systems can differ significantly in their reactivity and selectivity towards individual dyeings from the conventional peroxycarboxylic acids or peroxycarboxylic acid generating activators. ISO 105-C09 appears to be suitable for prediction of the effect of conventional peroxycarboxylic acids but shows deficiency in the assessment of new bleach systems such as perimidic acids.
Effect of Micelles on the Dynamic Surface Tension of Zwitterionic Surfactants
Authors: Delgado C. , López-Díaz D. , Merchán M. D. , Velázquez M. M.
Published: December 2013

The dynamic surface tension of micellar surfactant solutions was measured using the maximum bubble pressure method. The chosen surfactants were carboxy- and sulfo-betaines. At the beginning, surface tension decay curves are consistent with a diffusion-controlled adsorption. However, at long times these curves were analyzed by using the Fainerman model. From these experiments, the rate constants for demicellization were obtained. The micelle dissociation rate constant depends of the surfactant concentration, the concentration dependence is interpreted by Aniansson's theory, and the micelle dissociation constant independent of surfactant concentration was calculated. The rate constants found in this work are of the same order of magnitude as those obtained using classical techniques for fast reactions.
Micellar Characterisation of Saponin from Sapindus Mukorossi
Authors: Balakrishnan S. , Varughese S. , Deshpande A. P.
Published: December 2013

The micellar characteristics of a non-ionic, natural surfactant, saponin obtained from the soapnut tree, Sapindus mukorossi, were studied in aqueous solution. Critical micelle concentration of Sapindus saponin determined using conductivity measurements and UV absorption studies was 0.045 wt%. Increase in temperature and salt concentration led to decrease in the critical micelle concentration of Sapindus saponin. The critical micelle concentration was found to increase with increase in hardness of water and increase in pH. The micellar aggregation number was determined using cyclic voltammetry and was found to be between 13 and 21. The size of the Sapindus saponin micelles was determined using intrinsic viscosity measurements and was found to be independent of saponin concentration for concentrations above the CMC. Solubilisation of two types of crude oils and a vegetable oil was studied using micellar solubilisation technique. At lower concentrations of the surfactant, the micellar solubilisation of crude oils in saponin was better than synthetic surfactants like Triton X100® and SDS where as, the solubilisation of vegetable oil was better in synthetic surfactants.
Antagonisms between Surfactants: The Case of Laundry Detergents
Authors: Paye M. , Block C. , Hamaide N. , Hüttmann G.-E. , Kirkwood S. , Lally C. , Lloyd P. H. , Makela P. , Razenberg H. , Young R.
Published: December 2013

Interaction between surfactants forms micelles that typically lead to a reduction of the irritation potential of the mixture. The objective of this study is to illustrate that such antagonism between surfactants is applicable to actual cases of consumer products e.g. laundry detergent products. The Zein test is an in vitro assay measuring corn protein denaturation by solutions of surfactant(s) and often used to predict their acute irritation potential. The Zein test data for the surfactant mixtures from nine representative laundry detergents demonstrate that the protein denaturation by the mixtures is, in all cases, lower than the cumulative score of protein denaturation by the different surfactants tested separately. The data clearly indicate that antagonism occurs between the actual surfactants present in their exact proportions as found in the consumer laundry detergent products. These data support the view that the hazard classification of detergent products as (irritant) by the dangerous preparation directive should not be based on a simple cumulative score of the irritation properties of the individual components of the products.
Krafft Points and Cloud Points of Polyoxyethylated Nonionic Surfactants
Authors: Schott H.
Published: December 2013

Polyoxyethylated nonionic surfactants (POSs) are more soluble in cold than in hot water. On heating, they precipitate reversibly from aqueous solution at and above characteristic temperatures, which are called cloud points (CPs) because the solutions turn cloudy/opaque. The CPs of normally distributed POSs are correlated with the average number p of oxyethylene units per molecule by the linear equation (p – p0)/CP=A+B(p – p0). In a homologous series of POSs, the smallest value of p conducive to solubility in ice-cold water, p0, belongs to the surfactant with CP=0°. Its hydrophile-lipophile balance, HLB0, is a quantitative measure of the hydrophobicity of the parent fatty alcohols, CmH2m+1OH, fatty acids and alkylphenols. New CPs, especially of POSs with p approaching p0, are combined with published CPs in this study. The order of increasing HLB0 and hydrophobicity of the parent compounds, accompanied by decreasing CPs of their ethoxylates, is: saturated linear primary alcohols [m=18 (lowest HLB0=8.2), 16, 14.6, 13.3, 12.7, 12.0]<oleyl alcohol<saturated primary alcohols with multiple methyl branches (m=10, 13)<Guerbet alcohols (2-hexyldecanol, 2-butyloctanol)<p-nonyl (i.e., triisopropyl)phenol<p-octyl (i.e., diisobutyl)phenol<esterified saturated linear acids [m=18, 12 (highest HLB0=11.4)]. Interpolation by means of the equation above with the appropriate values of p0, A and B supplies the CP for any homologous POS belonging to one of the 14 groups investigated, based on its degree of ethoxylation p.
Detergent Phosphates and their Environmental Relevance in Future European Perspectives
Authors: Wind T.
Published: December 2013

This paper provides a generic overview of the relative contribution of different sources to the load of phosphorus (P) in surface waters in 18 European countries. Based on the current P-inputs into surface waters, future scenarios reflecting further reductions of P from municipal waste water are presented. A significant P-reduction can be achieved by improving the wastewater treatment situation and by introducing P-free product alternatives for laundry detergents. The remaining fraction of P in surface waters originating from automatic dishwashing detergents (ADD) only has a minor relevance for the aquatic ecosystem and may be reduced to a maximum of <1–4% when sewage treatment situation is improved. It can be concluded that ADD as P-source in the aquatic environment may not significantly contribute to the nutrient status, especially in eutrophication sensitive areas, where efficient P removal from sewages is regulated by the Urban Wastewater Directive (91/271/EEC). With respect to a requested evaluation of potential legislative steps by the EUDetergent Regulation (648/2004/EEC), a total ban of P in detergents seems not an appropriate measure to achieve significant reductions of P-concentrations in surface waters.
Importance of Micellar Lifetime and Sub-micellar Aggregates in Detergency Processes
Authors: James-Smith M. A. , Shekhawat D. , Shah D. O.
Published: December 2013

Micelles are known to be dynamic entities, rapidly breaking and reforming continuously. Micellar dynamics can be manipulated by the addition of non-ionic or oppositely charged cosurfactant to a sodium dodecyl sulfate solution. Using filtration through nanoporous membranes we have shown that sodium dodecyl sulfate micellar solutions are not only made up of micelles and monomers, but also contain a high concentration of sub-micellar aggregates. The concentration of sub-micellar aggregates decreases as the micellar stability increases. We have investigated the role of micellar stability and sub-micellar aggregates in cleaning of fabrics and hard surfaces such as porcelain dishes. After careful observation, it was determined that more stable micelles and lower concentrations of sub-micellar aggregates lead to more efficient detergency. In summary, it is desirable to have relatively stable micelles and the least number of sub-micellar aggregates for efficient detergency.
Sanitary Ware with Easy Cleaning and/or Antibacterial Properties
Authors: Agné T.
Published: December 2013

When the sanitary ware (ceramicplus) was launched it was one of the first product in consumer market that offered a surface based on nanotechnology. (ceramicplus) is a ceramic material that is modified by sol-gel methods, the so called wet-chemical nanotechnology thus creating a material of very low surface energy which results in a particularly dirt-repellent and easy-care surface. A further innovative surface is called (activecare). This ceramic glaze contains small quantities of antibacterial silver ions which prevent the build-up of bacteria and ensures hygienic cleanliness. Independent tests by renowned research institutes have verified the properties and long-term effect of (ceramicplus) and (activecare). Because of its water- and dirt-repellent properties (ceramicplus) requires minimum care without influencing the established good properties typical of ceramic materials. The roughness and hardness of ceramicplus is not significantly different from those of conventional ceramic glaze for sanitary ware. Scrubbing tests have proven that only the long-run use of highly abrasive cleaning agents – like scouring powder – may scratch the surface and impair the properties of (ceramicplus) as well as conventional ceramics. Thanks to the easy-care properties of these functionally modified ceramic surfaces such aggressive cleaning agents are not required for cleanliness.
Interaction between Lemna Minor and Anionic Surfactants
Authors: Ojeda C. A. , Castro M. J. L. , Torchinsky A. R. , Cirelli A. Fernández
Published: December 2013

The aim of this study was to determine the interaction between anionic surfactants and macrophytes. Two different types of surfactants were chosen for the study: SDS (non-aromatic) and LAS (aromatic). Lemna minor was the macrophyte of choice, an aquatic plant, useful for its selective removal of ammonia, its ability to cover the surface of water bodies, and to remove heavy metals from effluents. The experiments with L. minor were performed in the presence and absence of nutrients. The concentrations of surfactants used were similar to those which can be found in wastewater. Under these experimental conditions L. minor was not affected. Because of this, L. minor used in treatment ponds appears not to be affected by the presence of surfactants. Moreover it can diminish their concentration in effluents prior to its disposal in water bodies.
The Prediction of Microemulsion Properties: Molecular Theory and the Lattice Fluid Self-Consistent Field Theory
Authors: Blagojević S. , Potkonjak N. , Ilić M. , Kolarić B.
Published: December 2013

Structural features of microemulsions such as the droplet radius, thickness of the surfactant layer at the interface, number and distribution of molecules within a droplet are calculated using LSCF field theory. The theory was also used to calculate the composition ratio, interfacial tension (γ) and bending moment (c) of spherical interfaces between oil and water. Presented results show that LFSCF approach can be used to predict microemulsion properties.
Synthesis and Interfacial Properties of Dialkylbenzenesulfonates for Producting Low Interfacial Tensions
Authors: Wang Y.-X. , Zhao Y. , Hou Q. , Qi J. , Li Z.-S.
Published: December 2013

A new method of synthesis a series of pure dialkylbenzene sulfonates is described. The benzene ring carries a major alkyl substituent, consisting of a linear chain of sixteen carbon atoms long, and one additional methyl group. Products are charactered by EI-MS and 1H NMR. Experimental investigations have been conducted to explore the interfacial tension behavior of crude oil with dialkylbenzenesulfonates. The effects of various parameters such as surfactant concentration, salinity concentration on the interfacial tension of crude oil-water were investigated in detail. The transient low interfacial tensions in crude oil/alkali system were caused by the synergistic effects between surfactant and the active species generated at interface, but surfactant molecules plays the dominant role at equilibrium.
Surface Activity of Newly Nonionic Surfactants at Air/Water Interface and their Interaction with Clay and Teflon
Authors: Abdel-Rahem R. , Ayesh A. S.
Published: December 2013

The surface activity of newly nonionic hydroxyl mixed ether surfactants HMEnat air/water and solid/water interfaces was studied as a function of ethoxylation degree (n-value). The characteristics of this series of nonionic surfactant, including surface tension, critical micelle concentration cmc, adsorption onto hydrophilic saponite clay and hydrophobic Teflon are reported. The surface tension results indicate that cmc, surface tension after γcmc, and the minimum surface area per adsorbed HME-surfactant molecule Aminare all increased with n-value. Results of static light scattering are in agreements with those obtained using surface tension method. For HME-surfactants, strong adsorption measured by surface tension onto the hydrophilic synthetic clay mineral saponite. This result was also observed by atomic force microscopy AFM for HME9.7onto hydrophilic mica surface. On the other hand, the adsorption of HME-surfactant onto hydrophobic polytetraflouroethylene PTFE (Teflon) is less than that measured onto saponite. However, the adsorption at both surfaces has the same dependency on n-value.