N-Methylmelamines have recently gained importance as valuable compounds for manufacturing modified melamine formaldehyde resins and other polymer building blocks. A great advantage of these polymers is the reduction of the carcinogenic formaldehyde. Selecting the polymerization processes (e.g., substance polymerization, polymerization in solution) and controlling the polymerization reaction and properties of these novel materials requires knowledge of the properties of the individual melamine derivatives used as new building blocks. All possible permutations of N-methylmelamines were prepared, and reaction progress was monitored by GC/MS. 2,4,6-Tris(dimethylamino)-1,3,5-triazine was prepared to complete the series; this is, however, also a possible byproduct in various synthesis routes. The reaction conditions were optimized to obtain high yields of each derivative with the highest possible purity. The substances were characterized by NMR and IR spectroscopy, mass spectrometry, elemental analysis, and single-crystal X-ray diffraction. In addition, physical properties, such as solubility, melting points, and pKb values, were determined. The number of amino-, methylamino-, and dimethylamino groups has a significant effect on these properties. In summary, we found that by increasing the number of amino- and methylamino groups, solubility and pKb increase. With increasing number of amino groups, the compounds tend to form hydrogen bonds, and thus, the melting point shifts to higher temperature ranges where they start to decompose.

No abstract

Bulk material of Nd-doped Tl-1212 superconductors was prepared via a two-step procedure based on a wet chemical method to prepare precursor material followed by heat-treatment at 895 °C for 10 h. The samples with Nd stoichiometry of x = 0.05, 0.1, 0.15, 0.20 0.25 and 0.30 were characterized by XRD, electron microscopy and by resistance measurements. Oxygen stoichiometry of the specimens was analyzed. Lattice parameters were derived from x-ray diffraction and neutron diffraction measurements. The increase of the a-axis and the decrease of the c-axis as a function of the Nd content are discussed.

Novel linear polymers on the basis of allyl functionalized melamine derivatives, without using formaldehyde as cross‐linking agent, were created. Allylpentamethylmelamine and allyltetramethylmelamine were polymerized by free radical mechanism in substance. Allylpentamethyl‐melamine was also copolymerized with styrene by anionic polymerization. The new polymers offer a broad range of industrial application for melamine derivatives, not only in homopolymerization but also in the copolymerization with other monomers. For molar mass determination the polymer has been separated in different fractions by SEC and characterized by SEC and MALDI‐ToF mass spectrometry.

No abstract