Beiträge zur Schaumreinigung fester Oberflächen 2. Mitteilung: Schaumeigenschaften und Wirksamkeit

Foam Cleaning of Solid Surfaces 2. Foam Properties and Effectiveness Cleaning foams are very stable. Although the foam gives up almost the entire amount of liquid entrained in the lamella within 20 min, the original volume is retained. The highly alkaline solution released wets the soiled surface of the tile, swells the dried up protein rest and dissolves the same, which is subsequently removed by rinsing with water. The effectiveness of foam cleaning can be increased by up to 10% using longer periods of action of the foam on the soiled surface. Mechanical and heat treatment are of limited value in foam cleaning.     

Experimentelle Untersuchung zur Foulingneigung einer Polymerdispersion auf modifizierten Oberflächen

Fouling is economically and ecologically a key problem for the efficiency for production and processing of polymer dispersions. In this study, the fouling behavior of polymer dispersions on heated and cooled surfaces was investigated. Therefore, the dependency of the fouling on operational parameters (heat flux density, bulk temperature, concentration of solid, flow regime) and properties of the apparatus (surface modification, coating) was studied. Electropolished surfaces and certain sets of operational parameters were identified as fouling mitigating and easier to clean, respectively.     

Beiträge zum maschinellen Geschirrspülen 4. Mitteilung: Entfernen komplexer Anschmutzungen von Glasoberflächen

Contributions on Mechanical Dish Washing 4: Removal of Complex Soils from Glass Surfaces Under practical conditions, the soil on household crockery is composed of a mixture of fat, starch and protein residue. These diverse components mutually affect their adherence, and, consequently the ability of the cleansing liquid to remove them. Removal of starch is improved in the presence of casein residues; conversely, casein is more easily removed from glass in the presence of starch. Starch residues inhibit the removal of fat, however, this negative effect is compensated, if casein residues are simultaneously present. An attempt is made to explain the interactions between the individual components of the soil.     

Beiträge zum maschinellen Geschirrspülen 1. Mitteilung: Entfetten von Glasoberflächen unter den Bedingungen des maschinellen Geschirrspülens

Contributions on Mechanical Dish Washing 1: Defatting of Glass Surfaces Under the Conditions of Mechanical Dish Washing Tracer technique was used to study the dissolution of a film of butter fat or lard from glass surface during the conditions used in mechanical dish washing. Washing temperature was found to be the determining factor in the removal of fat residue. The major amount of the fat can be dissolved only at temperatures above its melting point, and, sufficient amounts of the cleansing agent ensure its stable emulsification, thus preventing the redeposition on the glass. Hot prewashing reduces the requirement of cleansing agent, since the quantity of cleansing increases linearly with the fat level of the goods to be washed. Polyethylene, because of its higher affinity to fat, is more difficult to defat than glass.     

Beiträge zur Analytik von Estersulfonaten

Contributions to the Analysis of Sulfonated Esters Several methods for the characterization and determination of α-Sulfo fatty acid methyl esters are described. The sulfonated ester is detected by thin layer chromatography on silica gel plates with tetrahydrofuran + acetone (1+9 v/v) as solvent and with pinacryptol yellow/UV-light for the visualization. Pyrolysis-gas liquid chromatogrphy with heating a sample/P₂O₅-mixture at 400°C yields the chain length distribution of the fatty acids initially used. The amount of an α-sulfo fatty acid ester is determined by extraction with i-propanol and by two-phase titration (Epton). the saponification product of the sulfonated ester is in the i-propanol insoluble part. For a quantitative determination of the α-sulfo fatty acid methyl ester by thin layer chromatography the sample solution is directly applied to the thin layer plate. A range of defined volumes, with increasing amounts of the sample are applied to the plate by means of an applicator. The chromatograms are visually compared. Ion chromatogrphy with the mobile phase, NH₃/Acetonitrile separates the α-sulfo fatty acid esters by chain-length. Determination is achieved by standards with defined chain-length.     

Beiträge zum maschinellen Geschirrspülen 2. Mitteilung: Entfernen von Stärkerückständen von Glasoberflächen

Contributions on Mechanical Dish Washing 2: Removal of Starch Residues from Glass Surfaces The use of ¹⁴C-labelled tobacco starch as indicator of potato starch enabled to study the removal of starch residues from glass surface by mechanical dish washing. It was found that the amount of starch applied could be reduced to as much as 11.5% during prewashing with cold tap water. The use of prewashing water at 45°C improves the swelling of dried starch residues. In contrast to removal of fat, the removal of starch residues requires a washing temperature of at least 55°C. However, even after an optimum combination of washing temperature, washing time and amount of cleansing agent, higher proportions of starch residues are retained on the glass surface than fat residue. At a maximum washing temperature of at least 50°C, the amount of starch residue remaining on the cleaned glass surface is greatly independent of the amount of starch applied to the glass surface.     

Beiträge zur Synthese von Orthocarbonsäureamiden

The formamidinium salts 11a, c as well as the nitrile 12 react with sodiumhydride/dimethylamine in the presence of trimethylborate to give the ortho formic acid amide 3a . The orthoamides 6a and 16 can be prepared from the iminium salts 15 and 14 , resp. by the same procedure. Treatment of the azavinylogous formamidinium salt 15 with sodiumhydride and piperidine or morpholine in the presence of trime‐thylborate affords the orthoamides 6c and 6d , resp. By transamination of the azavinylogous aminalester 5a are accessible the orthoamides 6b—d . The vinylogous orthocarbonic acid derivative 17 can be obtained from the salt 14 and sodium alcoholates. The action of sodiumhydride, dimethylamine and trimethylborate on the iminium salt 18 produces a mixture of the orthocarbonic acid derivatives 7a, 8a, 9a . When the guanidinium salt 20 is treated with the same reagents the ortho‐amides 3a and 10a are obtained. The reduction of the salt 20 with sodiumhydride in the presence of several activating reagents (e.g. tetrabutyl orthotitanate, aluminiumisopropylate, trimethylborate) affords the orthoamide 3a . The reduction of the iminium salts 18 and 24 does not proceed clean, giving mixtures of various orthoformic acid derivatives. The form‐amidine 25 can be prepared by reduction of the salt 15 with sodiumhydride/trimethylborate with good yields. By the action of the corresponding carbanions on the guanidinium salt 20 can be obtained the carboxylic acid orthoamides 26—33 . By the same procedure the orthoamides of alkyne carboxylic acids 36a—h, j—n are accessible.     

Beiträge zur galvanisierung von polymeren, 5. Untersuchungen zur morphologie der galvanischen kupferschicht

The structure of a 15–20 μm thick copper layer, which is deposited electrochemically on copolymers of acrylonitrile, butadiene and styrene from bathes containing additives is extremely distorted. This is caused by microstresses and paracrystalline lattice distortions. On the other hand, the structure of the copper layer deposited from a pure bath is independent of the chemical pre-conditioning of the polymer surface, necessary for plating, and equal to that of a high crystalline pure copper.     

Beiträge zur präparativen Adsorptionschromatographie auf dem Wachsgebiet

Preparative Adsorption Chromatography in the Field of Waxes The authors investigated the effect of impregnation of silicagel with different salts (chlorides of alkali, alkaline earths and Magnesium) on the adsorption of wax components.     

Das Beschichten von Oberflächen

The coating of different substrates is an important part of many industrial manufacturing processes. The fluids used in these processes have very different rheological properties. They are coated to solid surfaces with high substrate velocities by dipping, spraying, casting or by the use of knives, blades and rollers. The field of flow between two rotating rollers is influenced by the free surface of the fluid and the contact point between the three phases, solid roller, coating fluid, and the surrounding gas. Viscous, inertial, gravitational and capillary forces control the velocity field between the rollers. Stable fluid coatings that satisfy the increasingly stringent demands on the quality of their surface structure have to be created within certain limits of the forces occurring. In order to predict these limits, the flow fields have to be completely calculated. Therefore all three conservation equations and an additional equation for the position of the free surfaces are solved with consideration of the constitutive equations and possible wall slip effects of the coating fluids.