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 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.     

The influence of maltodextrins on the structure and properties of compression‐molded starch plastic sheets

Starch plastic sheets were prepared by compression molding of starch‐based plastic granulates. The granulates were prepared by extrusion processing of mixtures of granular potato starch and several maltodextrins (5% w/w) in the presence of glycerol and water as plasticizers and lecithin as melt flow accelerator. The materials were semicrystalline, containing B‐type, V_h‐type, and E_h‐type crystallinity. The properties were dependent on water content. For the materials, a brittle‐to‐ductile transition occurred at a water content in the range of 11–12%, which was in accordance with the observed glass transition temperature. The structural and mechanical properties were a function of starch composition and maltodextrin source as well as molding temperature. The amount of granular remnants and residual B‐type crystallinity decreased with increasing processing temperature. The amount of recrystallized single‐helical amylose increased with increasing temperature. At molding temperatures in the range of 180–200°C, a sharp decrease in starch molecular mass occurred. The influence of molding temperature was reflected in a sharp increase in elongation at molding temperature above 160°C and a gradual decrease in elastic modulus. The tensile strength showed an initial small increase up to 160°C and a sharp decrease at higher molding temperatures. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2207–2219, 1999     

Fourier transform infrared analysis of plasma-polymerized hexamethyldisiloxane

The plasma-induced polymerization of hexamethyldisiloxane onto solid surfaces is studied by FTIR. An inductively coupled RF reactor was used to produce the thin polymer coatings. Analysis of the plasma polymer indicates a long chain polysiloxane structure resulting from the removal of some methyl groups from the monomer structure. Increasing the plasma power level from 30 to 100 W increased the chain length in the resultant polymer as indicated by the widening and splitting of the Si–O stretching absorptions. Thermal aging of the vapor phase polymer at 120°C for 1 h in vacuum and at 410°C for 30 min in a nitrogen atmosphere revealed the removal of some methyl groups from the polymer structure with temperature. TGA runs on the vapor phase polymer at 20°C/min in air showed the polymer retaining almost 65% of its weight at 1000°C. The residue remaining after the TGA run had very little organic content and may represent a glass type silicate network. Wettability values determined on coated glass slides revealed the hydrophobicity of the coatings with water contact angle values > 100°. SEM micrographs showed uniform and featureless coating on glass fibers which was etched by boiling water and was attributed to the loss of vapor phase polymer on the surface.     

Gasification of coals treated with non-aqueous solvents. 1. Liquid ammonia treatment of a bituminous coal

A Japanese bituminous coal was treated with liquid ammonia at temperatures up to 120 °C. Extract was separated from the treated coal by washing with benzene-ethanol mixture. The amount of extract was about 2% in a single treatment at 120 °C and some additional extract was obtained by successive treatments. Particles of the residue had cracks and showed an increase in surface area. The ammonia-treated coal was found highly reactive toward gasification with hydrogen at high temperature when catalysed by nickel.     

Development of degradable polymer composites from starch and poly(ethyl cyanoacrylate)

This report describes the development of degradable polymer composites, which can be made at room temperature without special equipment. The developed composites are made from poly(ethyl cyanoacrylate) and starch. Ethyl cyanoacrylate monomers are mixed with starch and the polymerization reaction of these monomers was initiated by dissociated OH^‐ ions from moisture on the surface of the starch. After the polymerization, the body of starch granules acts as filler and the micrometer‐scale gaps formed by starch granules are filled with the poly(ethyl cyanoacrylate). The glass transition temperature of the composite matrix ranges from 106°C to 113°C and thermal degradation begins around 160°C. The polymer composites produced by this procedure contain 50–64 wt% of starch and have compressive strengths of 80 (±10) MPa. Optimum starch composition for these composites is ∼60 wt%. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Selektive Härtung von Fetten und Fettsäuren mit Sulfiden der Übergangsmetalle als Katalysatoren

Selective Hydrogenation of Fats and Fatty Acids with Sulfides of Transition Metals as Catalysts Sulfides of some transition metals are suitable as catalysts for the selective hydrogenation of fats and fatty acids. Ni₃S₂, a stoichiometrically, thermally and crystallographically defined compound is especially active. Also mixed catalysts containing tungsten sulfide and molybdenum sulfide besides Ni₃S₂ are sufficiently active. The same is true for cobalt sulfide catalysts, whereas molybdenum sulfide and tungsten sulfide exhibit considerably lower activities. The conditions of hydrogenation are essentially the same as customary: temperature range 180° to 210°C for fats, 200° to 220°C for fatty acids, hydrogen pressure 2–25 kg/cm², catalyst concentration 0.05 to 2 parts by weight of metal sulfide per 100 parts of fat or 0.5–5 parts by weight of metal sulfide per 100 parts of fatty acids. Using the above catalysts, the selectivity of S₃₁ or S₂₁ attained in the steps triene (polyene → monoene or diene → monoene is over 75. The remaining double bonds in the hydrogenated product possess almost exclusively the trans configuration. The above catalysts are resistant to sulfur compounds and they exhibit exceptional longevity. The regeneration can be performed with ease. Consequently, the pretreatment of the material to be hydrogenated can be limited to washing and drying.     

TSD-Untersuchungen zum Einfluß von Wasser auf die molekularen Beweglichkeiten in Polyamid-6

Molecular motions in nylon 6 are studied by thermally stimulated discharge (TSD) techniques. The effect of absorbed water on the relaxation behaviour of nylon 6 is discussed. The γ relaxation process at ?145°C is attributed to local segmental motions in the amorphous phase. The intensity of the γ relaxation is reduced and broadened by absorbed water. The molecular origin of the β relaxation process in the temperature range between ?80 and ?60°C is associated with localized reorientational motions of chain segments involving nonchain-bonded or weakly bonded amide groups. It is quite likely that also rotational rate processes of water molecules bonded to CO-groups contribute to the β process. The intensity increases are due to added water, since associated water molecules are involved with those molecular motions. The α relaxation process at 70°C is associated with large-scale segmental motions at the glass transition. The chain mobility is increased by added water and gives rise to an α peak near 50°C. The α′ relaxation process in the temperature range between 100 and 110°C may either be associated with reorientational motion of stretched chain segments or with the beginning of a crystalline transformation of the γ phase into the monoclinic α form. The temperatures of TSD-peaks correspond to alternating current loss data at a frequency of 5·10^?2 Hz.     

Effects of drying process for amorphous waxy maize starch on theophylline release from starch‐based tablets

Physical properties and theophylline‐release profiles of compressed tablets prepared with amorphous waxy maize starches dried using different methods were examined. A gelatinized waxy maize starch paste (10% solids in water) was either freeze‐dried or oven‐dried (40 or 105°C) until the moisture content reached to <5%. To form the tablets, the dried amorphous starch powders, either with or without theophylline (3 : 10, w/w), were remoistened to a water content of (17 ± 0.2)%, and compressed into tablets. The drying process applied to the amorphous starch powders affected both the compactness and swelling behavior of the tablets. Although no crystallinity was detected in all the starches tested, X‐ray diffraction patterns indicated that starch chains dried at the lower temperature (40°C) are allowed more time to re‐associate during the drying process than those dried at the higher temperature (105°C). The freeze‐dried starch powders formed tablets characterized by greater compactness and rigidity than was observed in the oven‐dried starch samples. The drug release of the tablets prepared with the starch dried at the higher temperature (105°C) occurred at a much slower rate than that of the tablets made with the starch dried at the lower temperature (40°C). The drug release characteristics of the freeze‐dried starch tablets were nearly identical to those of the tablets prepared with the starch dried at 105°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Polymerisation von Vinylchlorid bei Atmosphärendruck 1. Polymerisationssysteme zur Herstellung von U-PVC

A method for polymerization of vinylchloride (VC) at atmospheric pressure is described, in which the gaseous monomer is polymerized with K₂S₂O₈ as an initiator at 45°C to 60°C. The amount of the polymer formed (so-called U-PVC) as a function of the reaction time depends on the rate of monomer flow. The reaction rate increases with higher initiator concentration as well as with increasing temperature. It is also possible to initiate the polymerization with the redox-system K₂S₂O₈/Na₂SO₃/Cu²⁺ within the range of 0°C to 20°C. By means of transmission electronmicroscopic (TEM) investigations the particle size and particle size distribution as a function of polymerization time and temperature was determined.     

Eine empirische Methode zur Bestimmung der Emulgierfähigkeit von Pflanzenlecithinen in O/W-Systemen

An Empiric Method to Determine the Emulsifiability of Vegetable Lecithins in O/W-Systems The following method has been developed to evaluate the emulsifying effect of native, fractionated and modified vegetable lecithins. The lecithin which is to examine is solved in the ratio 1:9 in a fat mixture with the melting point of 32°C and the solution is given on the surface of 50 ml of water with 50°C, in a graduated cylinder. After 30 min. time of rest the cylinder is turned by hand or by means of a mechanic swinging device 20 times in 20 seconds for 180° about its transverse axis. Afterwards it is placed in a thermostat, with a temperature of 50°C. The time necessary to separate 25 ml water is determined. The thus defined half-life is characteristic for the emulsifying effect of the lecithin. The variation coefficient of the results is about 10% for mechanically emulsifying. The practicability of this method is explicated in many examples.     

Autonomic self‐healing of poly(vinyl butyral)

The self‐healing behavior of poly(vinyl butyral) (PVB) is evaluated below the glass transition temperature T_g. It is found that PVB shows autonomic self‐healing even at room temperature, although T_g is around at 76°C. Furthermore, a large amount of water is found to be adsorbed on the surface of the film. This is attributed to the surface localization of hydroxyl group in PVB, which is confirmed by X‐ray photoelectron spectroscopy. Since the surface is plasticized by water, the scar applied by a razor blade is healed even in the glassy state of the bulk. Moreover, the healing efficiency is enhanced at high humidity condition, owing to the pronounced plasticizing effect by water. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42008.     

Contribution a l'etude des groupements superficiels des noirs de carbone a l'aide de reactifs gazeux: Evolution de l'acidité superficielle du sphéron 6 au cours de traitements thermiques

The Spheron 6 surface acidity has been investigated by adsorption of ammonia at 70°C and microcalorimetry. The carbon samples are degassed at temperatures up to 950°C. The effects of degassing temperature on the adsorption isotherms of ammonia are shown in Fig. 2. Up to 350°C, the isotherms are characterized by a very slight decrease in the total amount adsorbed. On the contrary, these amounts considerably decrease for higher degassing temperatures. The differential heats of adsorption (Fig. 3), which are initially close to 100 kJ/mole, are shown to decrease with the amount of adsorbed ammonia: the higher the degassing temperature, the greater the decrease. By desorption, the adsorption of ammonia is found partly irreversible. By readsorption it is possible to measure the differential heat of the reversible adsorption and to deduce from it the differential heat of the irreversible adsorption (Fig. 4) as well as the amount irreversibly adsorbed, i.e. chemisorbed.The amounts of chemisorbed ammonia are found to be respectively 0.36 ± 0.01 × 10^?6 mole m² at 150°C and 0.29 ± 0.01 × 10^?6 mole m^?2 at 350°C. With the surface covering the differential heat of chemisorption of ammonia slightly decreases from 105 to 88 kJ. mole^?1.These values suggest that carboxyl groups are responsible for irreversible adsorption of ammonia. This assumption has been checked by various experiments: the irreversible uptake of ammonia lies in the same range as the number of carboxyl surface groups determined by chemical analysis of functional groups (Table 1); the evolving of H₂O during the decomposition of the ammonium salt formed by reacting with ammonia has been observed and is probably correlated with the irreversible uptake of ammonia (Fig. 8); moreover it must be pointed out that irreversible adsorption of ammonia disappears after methylation of sample by diazomethane (Figs. 5 and 6). Then, the amounts of carboxyl groups can be determined by measuring the irreversibly adsorbed ammonia.This method has been applied to the study of the thermal stability of functional groups. Carboxyl groups are shown to be quickly decomposed by heat treatment above 500–600°C (Fig. 8).It appears from our experiments that the oxidation at constant temperature followed by a cooling under nitrogen is unable to regenerate functional groups on the surface of carbon after their removal at 950°C. On the contrary, by an oxidation at decreasing temperature it is possible to regenerate functional groups because they are stabilized by the oxidising atmosphere.The groups thus created behave like those initially present on Spheron 6: particularly the graph of the thermal elimination of carbon dioxide presents two peaks (Table 2, Fig. 12). The amount of regenerated carboxyl groups is found to be 0.25 × 10^?6 instead of 0.36 × 10^?6mole m^?2 on untreated Spheron 6.     

Removal of Cu2+ Ions from Aqueous Solutions by Starch-Graft-Acrylic Acid Hydrogels

Gelatinized starch was prepared by constantly stirring a mixture of starch and water at 95°C for 1 hour. Starch-graft-acrylic acid (S-g-AA) hydrogels were prepared by grafting acrylic acid (AA) [monomer/starch (w/w) 0.5–1.5] onto gelatinized starch with ceric ammonium nitrate as initiator under nitrogen atmosphere. The surface morphology of samples was studied using a scanning electron microscope (SEM). The hydrogels were evaluated for the removal of Cu²⁺ ion from aqueous solutions at different pH. The concentration of Cu²⁺ ion in aqueous solution was kept constant at 4 mmol/L. The metal ion removal capacities changed depending on treatment time, initial pH of the solution, and monomer/starch (w/w) ratio of the S-g-AA hydrogels. Cu²⁺ ion removal capacities were determined by atomic absorption spectrometer (AAS).     

Über die Bildung von Artefakten bei der Dämpfung von Speiseölen und -fetten

The Formation of Artefacts during Deodorization of Fats and Oils Various artefacts are formed during deodorization of fats and oils. Their amount depends on the process parameters, particularly temperature and time of deodorization. The design of the equipment as well as the fatty acid composition of the fats and oils also have some influence. We investigated the formation of trans-isomers as well as of dimeric or oligomeric triglycerides in various fats and oils of different degree of unsaturation by means of IR-spectrometry and capillary GLC on one hand and by gel permeation chromatography on the other hand. The amount of the formation of artefacts is insignificant up to 240°C. At somewhat higher temperatures the amount clearly increases and in the temperature range 260-270°C a steep increase can be observed. Under process conditions as applied in the industrial practice of to-day objectionable concentrations of artefacts are never formed.     

Starch‐grafted polypropylene: Synthesis and characterization

Graft copolymerization of starch has been carried out onto preirradiated polypropylene (PP) in an aqueous medium using benzoyl peroxide (BPO) as the radical initiator. The maximum percentage of grafting (115%) of starch onto PP was obtained at optimum conditions of BPO concentration, 1.239 × 10⁻³ moles; temperature, 65°C; in 120 min. using 30 mL of water. Swelling studies were carried out in pure, binary, ternary and quaternary solvent systems comprising of water, ethanol (EtOH), dimethylsulphoxide (DMSO), and N,N‐dimethylformamide (DMF) in different ratios. Maximum swelling is observed in DMSO and DMF, followed by EtOH and least in water for true graft. Water retention studies of pristine PP and PP‐g‐Starch (both composite and true graft) were investigated at different time periods, temperature and pH. The composite contains grafted PP, unreacted starch and unreacted PP whereas true graft is the product from which both unreacted polymers have been removed. Maximum % water retention of PP‐g‐Starch (composite) (110%) was observed in 8 h at 50°C in neutral medium (pH = 7). The graft copolymers were characterized by FTIR, DTG, DTA, TGA, and SEM. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Cold enzyme hydrolysis of wheat starch granules

Three α-amylase enzymes were used to hydrolyze wheat starch granules suspended in water below the gelatinization temperature. The rates of hydrolysis were determined at various temperatures, pH, enzyme and starch concentrations. Barley amylase was found to be the “best” enzyme when used at pH 4.5, 45°C and starch and enzyme concentrations of 30 and 8 mg/mL respectively. It was found that under these conditions, 98% of the starch granules were hydrolyzed in 3 hours, the same amount of time used in the industrial cooking process of soluble starch. Starch particles were observed to be attacked at specific points on the surface and then hydrolyzed from the inside-out. Some granules were hydrolyzed at a very fast rate with a first order rate constant estimated to be 40 h^?1; but most granules were hydrolyzed slowly according to the Michaelis-Menten model and the best fit parameters were found to depend on enzyme type, pH and temperature.     

Starch–poly(ethylene-co-acrylic acid) composite films. Effect of processing conditions on morphology and properties

Formulations containing 4 parts cornstrach, 5 parts poly(ethylene-co-acrylic) (EAA), 1 part urea, and 1.6 parts of either water or aqueous ammonia were extruded at either 110–120°C or 150–160°C; and the resulting extrudates were then extrusion-blown into films. Complex formation between EAA and starch was measured by either X-ray diffraction or by solvent extraction of uncomplexed EAA. Although the processing temperature had only a minor effect on the amount of EAA complexed by starch, use of aqueous ammonia rather than water in these formulations increased the amount of complexed EAA by about a factor of 2. In films prepared with aqueous ammonia, the polysaccharide phase was present as submicron-sized domains. When ammonia was omitted from these formulations, the polysaccharide phase was less uniform in size and contained particles that were over an order of magnitude larger than those observed with ammonia.     

A dielectric study of water uptake in epoxy resin systems

The influence of epoxy resin formulation on the nature and extent of moisture is studied using dielectric and gravimetric analysis for samples cured at 40, 50, 60, and 70 °C and aged at 50 °C and 70 °C. The equilibrium moisture uptake depends on the difference between the glass transition and aging temperature. Dielectric relaxation data measured from 1 to 3 × 10¹⁰ Hz indicates the presence of water in at least two different environments. The high frequency relaxation ca. 1 × 10¹⁰ Hz is associated with water clustered in nano‐voids, whereas the relaxation at 10⁵ Hz arises from a combination of OH pendant group reorientation motion coupled with that of molecularly dispersed water molecules. A correlation exist between the dielectric permittivity and the amount of moisture absorbed. Water initially resident in voids is re‐dispersed with aging into the resin matrix aiding plasticization and allowing densification of the matrix. The extent to which changes occur depends on the chemical functions forming the matrix and densification leads to a drop in the amount of water absorbed. In the complex resin systems, water interacts with both OH groups and polyether of the amine curing agent which is not possible with the aliphatic diamine in the simple system.] © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44717.     

Upgrading of oil sand coke residues

The application of molten caustic leaching, MCL, for the desulphurization and ash removal from delayed and fluid oil sand coke residues has been studied at a temperature of 400°C. The variables studied were sodium hydroxide to coke weight ratio (1.0–2.0), reaction time (0–2 h) and coke washing conditions. The results obtained indicate that both coke samples were amenable to molten caustic leaching. The optimum reaction time for desulphurization and ash removal for both cokes at 400°C was determined to be 30 min. It is shown that the desulphurization conditions that will concurrently give high carbon recoveries correspond to a desulphurization index of 80% for both coke residues.