Beiträge zum Vernetzungs- und Abbauverhalten von Acrylelastomeren

The aim of this investigation was to obtain additional knowledge of the curing mechanism and the aging properties of acrylic polymers containing active chlorine. These were cured with amine or metal-soap/sulphur combinations. For this purpose, we used sulphur, chlorine, and nitrogen analyses, together with measurements of crosslink density and stress-relaxation. These investigations were partly made with vulcanisates based on technical acrylic polymers, and partly with crosslinked products of homo- and copolymers containing chlorine. Using the amine curing system, the diamine, after vulcanisation, is completely incorporated. Curing with metal-soap/sulphur combinations sulphur crosslinks are formed. The crosslink density is proportional to the concentration of amine or potassium-stearate in the compound. Comparing polyethylacrylate polymers containing vinyl-chlorecetate and 2chloroethyl-vinylether comonomers one always h d s the higher crosslink densities in polyethylacrylat/vinylchloracetat copolymers. We proved by stress relaxation measurements that scission of the network occurs at the crosslinks during air aging. Using amine as the curing agent oxidativedegradation exceeds the thermal one. In case of metal-soap/sulphur curing system thermal degradation exceeds the oxidative portion. Remarkable differences in aging properties between the two types of polymers could not be found. These results fit with our conception of the types of networks built up duringvulcanimtion, based on the other examinations.     

Polymerisation von Butadien-(1,3) mit Tetrabenzyltitan-Verbindungen enthaltenden Systemen

Tetrabenzyltitanium and its o-halogenbenzyl derivates have only a small activity for polymerizing butadien. Aluminium trialkyls accelerate the catalytic activity. A very suitable system for preparing 1,4-cis or 1,4-trans polybutadien under normal pressure is formed by tetrabenzyl titanium and aluminium chloride as a co-catalyst.     

Beiträge zum reaktiven Verhalten von Sulfinsäurederivaten. VI [1]. Zur α-Aminomethylierung von N-Cyclohexylsulfinamiden

Contributions towards the Reactivity of Derivatives of Sulfinic Acids. Vi. The α-Aminomethylation of N-Cyclohexylsulfinamides N-Cyclohexyl-N-aminomethylsulfinamides are prepared under the conditions of a MANNICH reaction from N-cyclohexyl-N-p-toluene-, -p-chlorobenzene-, -p-bromobenzene- and -methyl-sulfinamides with formaldehyde and secondary amines or O,N-acetals, respectively. The resulting N-amino-methylsulfinamides have been characterized by i.r.-, ¹H-n.m.r.-spectra as well as by some reactions with electrophilic or nucleophilic compounds.     

DIELS-ALDER-Reaktionen. IV. Untersuchungen über die Mischdimerisierung von Cyclopentadien mit Butadien-(1,3)

Diels-Alder Reactions. IV. Studies on the Codimerization of Cyclopentadiene with Butadiene The reaction of cyclopentadiene with butadiene between 120°C and 170°C yields only about 35% exo/endo-2-vinylbicyclo[2,2,1]heptane-(5); 4,7,8,9-tetrahydroindene, dicyclopentadiene and the homodimers of butadiene are formed as inevitable by-products. The parallel and consecutive reactions which take place in the system cyclopentadiene/butadiene were separately studied as far as possible, and the activation parameters were determined. Surprisingly, in the homodimerization of butadiene the activation parameters for the symmetry-allowed formation of 4-vinylcyclohexene and the symmetry-forbidden formation of trans-1,2-divinylcyclobutane and of cyclooctadiene-(1,5) show very similar values.     

Beiträge zum Reaktionsverhalten der Oxo-alkan-phosphonsäuredialkylester

Contributions towards the Reaction Behaviour of Dialkyl Oxo-alkane-phosphonates Dialkyl oxo-alkane-phosphonates react with dioles and their thio-analogues forming ketales and thioketales 1–19 of the general formula The arylhydrazones prepared from substituted diethyl oxo-alkane-phosphonates and aromatic diazonium salts can be cyclized without preliminar isolation to give the diethyl indolyl-2-phosphonates 20 . 1-Arylidene-2-oxo-propane phosphonic acid esters 22 and 23 react with ethyl β-aminocrotonate through MICHAEL addition followed by enamine formation to yield alkyl dihydropyridine-3-phosphonates 24 and 25 . I. R. data of the compounds prepared are recorded.     

Beiträge zur galvanisierung von polymeren, 7. Metallisierung von epoxidharzen mit hilfe von haftvermittlern

Epoxy resins can be coated with a metal after being covered with a platable adhesive. Such an adhesive consists of a partly epoxidized styrene-butadiene-styrene block copolymer, an epoxy prepolymer and an amine curer. The contents of these substances in the mixture and the nature of the amine influence the peel strength of the metal layer. The maximum peel strength with a value of about 45 N/25 mm was obtained after using a low molecular weight amine, while values of only about 10 N/25 mm could be obtained with amines of higher molecular weight.     

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.     

Sensibilisierte Photooxidation von Butadien-(1,3)-sultamen-(1,4)

Sensitized Photooxidation of Butadiene-(1,3)-sultames-(1,4) The sensitized photooxidation of the butadiene-sultames 1a–d gives 2-aryl-3,5-dimethyl-5-hydroxy-1,1,6-trioxo-5,6-dihydro-2H-1,2-thiazines 2a–d in yields of 60%. The compounds 2a–d are instable against bases and acids. With triethylamine the N-aryl-5-hydroxypyrrolin-2-ones 5a–d are formed by SO₂-extrusion. With alkali 2b reacts to 5b and cis-β-acetyl-methacrylic acid 4 . ¹H- and ¹³C-n.m.r. spectroscopic data of 2 and 5 are given.     

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.     

Vinylpolymerisation mit reduzierenden Übergangsmetallverbindungen. VII. Polymerisation von Methylmethacrylat in Gegenwart von Molybdän(III)-chlorid-Sulfoxid-Systemen

Vinyl Polymerization Initiated by Reducing Compounds of Transition Metals. VII. Polymerization of Methyl Methacrylate in the Presence of Molybdenum(III) Chloride/Sulfoxide Systems The polymerization of methyl methacrylate initiated by the molybdenum(III) chloride/dimethyl sulfoxide redox system was carried out at 70° in 1, 4-dioxane. The rate of polymerization can be described by the equation R_p = k · [MoCl₃]^0,5 · [DMSO]^0,5 · [MMA]^1,0. The overall activation energy was estimated to be 36.0 kJ/mol. It was found that diethyl, dipropyl, dibutyl, diphenyl and dibenzyl sulfoxides could also initiate the polymerization of methyl methacrylate in the presence of molybdenum(III) chloride, whereas vanadium(II) chloride, vanadium(III) chloride, titanium(III) chloride and chromium(II) acetate are inactive in combination with sulfoxides.     

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 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.     

DIELS-ALDER-Reaktionen. V. Kinetische Modellierung der bei der Mischdimerisierung von Cyclopentadien mit Butadien-(1,3) ablaufenden Reaktionen

Diels-Alder-Reactions. V. Kinetic Modelling of the Reactions Taking Place in the Codimerization of Cyclopentadiene with Butadiene With the aid of independently determined rate constants of the 11 reactions which must be considered, the dependence of concentration on time for the most important products of the reaction between cyclopentadiene and butadiene can be calculated only with unsufficient accuracy. Using optimization procedures (sequential simplex procedure and the procedure of SILLEN ) it is possible, however, to recalculate rate constants from the experimental dependence between concentrations and time. These recalculated rate constants permit a calculation of the dependence between the concentrations of all products and the reaction time, which very well agrees with the experiment.     

Beiträge zum Reaktionsverhalten von Derivaten der Imidodithiokohlensäure. II [1]. 7-Hydroxythiazolo[4,5-b]pyridone-(5)

Contributions to the Reaction Behaviour of Derivatives of Imidodithiocarbonic Acid. II. 7-Hydroxythiazolo[4,5-b]pyrid-5-ones Derivatives of cyanimidocarbonic acid 1 react with ethyl γ-bromoacetoacetate to ethyl thiazolylacetates 2 which are converted into 7-hydroxythiazolo[4,5-b]pyrid-5-ones 3 by acid or base catalyzed cyclisation. These compounds can be alkylated as well as acylated. The 7-hydroxy group is exchangeable for chlorine. Furthermore in position 6 electrophilic sulfonation can take place.     

Beiträge zur galvanisierung von polymeren, 10. Metallisierung von copolymeren aus acrylnitril und butadien nach vorbehandlung mit ozon

Copolymers containing acrylonitrile and butadiene can be coated with metal electroless. There is only a small influence on the metal-to-polymer-adhesion with the time of treatment with ozone. The adhesion increases with the content of acrylonitrile and with the molecular weight of the polymer. Peel strength values have been measured up to 150 N/25 mm because of the cohesive fracture inside the polymer. The highest values of adhesion have been measured on samples having nearly the same values of the critical surface tension like those of the electroless deposited nickel-layer. Caverns supporting a mechanical staying of the metal have not been observed.     

Beiträge zur galvanisierung von Polymeren, 9. Analyse der Polymeroberfläche nach anwendung von nassen beizen mit radioaktiv markierten Komponenten

Using pre-etchings containing chromium trioxide, phosphoric acid, and sulphuric acid the residual compounds of chromium, phosphor, and sulphur are tied irreversibly on the surface of polypropylene and ethylene-propylene-copolymers. The staying depends on the morphology of the polymer surface and obtains first maxima after short times of etching. The covering of the polymers influences the peel strength of the galvanically deposited metal layer. Residual sulphuric compounds have a stronger influence than phosphoric compounds. Residual chromium compounds exert no effect on the peel strength.