Darstellung der zahlentheoretischen FunctionE(x) durch eine unendliche Reihe

Ohne Zusammenfassung     

Über die Eigenschaften des α-Metaxylylhydrazins und seine Einwirkung auf Acetessigester

Ohne Zusammenfassung     

Die Reaktion von Oxycellulose (oxydierter Cellulose) mit Ne?lers Reagens

Ohne Zusammenfassung     

Thermoplastic resins,polyquats, and membranes based on epoxies

High-molecular-weight branched-addition polymers made from oligomeric solid epoxy resins and amines carrying two active hydrogen atoms are described. The reaction with aliphatic amines like ethanolamine, 2-ethylhexylamine, or piperazine can easily be controlled carrying out the polymerization in about 15% solutions of boiling 2-methoxyethanol. Less basic derivatives of aniline and epoxy resins are processed at 200°C in the molten state. Polymers with M _n up to 33,000 and M _w to 720,000 are obtained. Properties of films and injection moldings are described. The tertiary nitrogen atoms present in the polymer chain can be quaternized with alkylating agents, like dimethylsulfate, methyliodide, or trimethyl phosphate. Thin membranes cast from the polyquats thus obtained exhibit a good flow rate for water and a high salt rejection under reverse osmosis conditions.     

Cure of epoxy resins with cyanoacetamides

Cyanoacetamides are a novel class of curing agents for epoxy resins. Since reaction products of epoxy compounds with cyanoacetamides have not yet been described, we investigated the reaction of phenyl-glycidylether (PGE) and N-isobutylcyanoacetamide (NICA) under the conditions of the epoxy cure (120–150°C). Twenty-two fractions of the reaction product have been separated by preparative TLC and characterized by FD and MS mass spectroscopy. The structures of 10 reaction product have been elucidated by MS, NMR, and IR techniques. They belong to the classes of cyclic urethanes, spiro-dilactones, cyclo-oxa-1-hepten-4-one-2, pyrimidones, aminocrotononitrile, and tertiary amine. This complex model reaction mixture does not enable us to propose a curing mechanism. However practical cure of Bisphenol A diglycidylether (BADGE) yields clear and tough solids with a glass transition temperature up to 200°C, good mechanical strength, and high adhesion to metal surface. Cyanoacetamides are latent hardeners requiring a curing initiator. Since N-4-chlorophenyl-N′-dimethylurea is a latent initiator, liquid, homogeneous, storage stable “one shot” systems can be formulated which harden quickly above 120°C. Heat aging properties of cured specimens are reported. A series of novel liquid, resinous, and crystalline cyanoacetamides and their potential as curing agent are described.